Add `bool` return type where possible

Signed-off-by: Maurício Meneghini Fauth <mauricio@fauth.dev>

100 files changed, 295 insertions, 991 deletions

diff --git a/libraries/classes/Bookmark.php b/libraries/classes/Bookmark.php
index 14e2b17e3b..7e207cdae1 100644
--- a/libraries/classes/Bookmark.php
+++ b/libraries/classes/Bookmark.php
@@ -115,8 +115,6 @@ class Bookmark
     /**
      * Adds a bookmark
      *
-     * @return bool whether the INSERT succeeds or not
-     *
      * @access public
      */
     public function save(): bool
@@ -134,14 +132,12 @@ class Bookmark
             . "'" . $this->dbi->escapeString($this->query) . "', "
             . "'" . $this->dbi->escapeString($this->label) . "')";
 
-        return $this->dbi->query($query, DatabaseInterface::CONNECT_CONTROL);
+        return (bool) $this->dbi->query($query, DatabaseInterface::CONNECT_CONTROL);
     }
 
     /**
      * Deletes a bookmark
      *
-     * @return bool true if successful
-     *
      * @access public
      */
     public function delete(): bool
@@ -155,7 +151,7 @@ class Bookmark
             . '.' . Util::backquote($cfgBookmark['table'])
             . ' WHERE id = ' . $this->id;
 
-        return $this->dbi->tryQuery($query, DatabaseInterface::CONNECT_CONTROL);
+        return (bool) $this->dbi->tryQuery($query, DatabaseInterface::CONNECT_CONTROL);
     }
 
     /**
diff --git a/libraries/classes/Cache.php b/libraries/classes/Cache.php
index 86229ec0d7..60a36f45d9 100644
--- a/libraries/classes/Cache.php
+++ b/libraries/classes/Cache.php
@@ -19,8 +19,6 @@ class Cache
      *
      * @param string $cacheKey The key to use
      * @param mixed  $value    The value to cache
-     *
-     * @return bool Depends on if the value could be cached
      */
     public static function set(string $cacheKey, $value): bool
     {
@@ -56,8 +54,6 @@ class Cache
      * Remove a cached value
      *
      * @param string $cacheKey The key to use to remove the value
-     *
-     * @return bool Depends on if the value could be removed
      */
     public static function remove(string $cacheKey): bool
     {
@@ -68,8 +64,6 @@ class Cache
 
     /**
      * Purge all cached values
-     *
-     * @return bool Depends on if the cache could be purged
      */
     public static function purge(): bool
     {
diff --git a/libraries/classes/Config.php b/libraries/classes/Config.php
index b320073731..b5f85f4157 100644
--- a/libraries/classes/Config.php
+++ b/libraries/classes/Config.php
@@ -384,8 +384,6 @@ class Config
 
     /**
      * loads default values from default source
-     *
-     * @return bool success
      */
     public function loadDefaults(): bool
     {
@@ -727,8 +725,6 @@ class Config
 
     /**
      * check config source
-     *
-     * @return bool whether source is valid or not
      */
     public function checkConfigSource(): bool
     {
@@ -931,7 +927,7 @@ class Config
     public function isHttps(): bool
     {
         if ($this->get('is_https') !== null) {
-            return $this->get('is_https');
+            return (bool) $this->get('is_https');
         }
 
         $url = $this->get('PmaAbsoluteUri');
@@ -1019,8 +1015,6 @@ class Config
      * removes cookie
      *
      * @param string $cookieName name of cookie to remove
-     *
-     * @return bool result of setcookie()
      */
     public function removeCookie(string $cookieName): bool
     {
@@ -1053,8 +1047,6 @@ class Config
      * @param string $default  default value
      * @param int    $validity validity of cookie in seconds (default is one month)
      * @param bool   $httponly whether cookie is only for HTTP (and not for scripts)
-     *
-     * @return bool result of setcookie()
      */
     public function setCookie(
         string $cookie,
@@ -1165,8 +1157,6 @@ class Config
      * isset cookie
      *
      * @param string $cookieName The name of the cookie to check
-     *
-     * @return bool result of issetCookie()
      */
     public function issetCookie(string $cookieName): bool
     {
diff --git a/libraries/classes/Config/FormDisplay.php b/libraries/classes/Config/FormDisplay.php
index e00f687a6f..f45022ec48 100644
--- a/libraries/classes/Config/FormDisplay.php
+++ b/libraries/classes/Config/FormDisplay.php
@@ -160,10 +160,8 @@ class FormDisplay
      * @param bool $allowPartialSave allows for partial form saving
      *                               on failed validation
      * @param bool $checkFormSubmit  whether check for $_POST['submit_save']
-     *
-     * @return bool whether processing was successful
      */
-    public function process($allowPartialSave = true, $checkFormSubmit = true)
+    public function process($allowPartialSave = true, $checkFormSubmit = true): bool
     {
         if ($checkFormSubmit && ! isset($_POST['submit_save'])) {
             return false;
@@ -579,10 +577,8 @@ class FormDisplay
      * @param array|string $forms            array of form names
      * @param bool         $allowPartialSave allows for partial form saving on
      *                                       failed validation
-     *
-     * @return bool true on success (no errors and all saved)
      */
-    public function save($forms, $allowPartialSave = true)
+    public function save($forms, $allowPartialSave = true): bool
     {
         $result = true;
         $forms = (array) $forms;
@@ -755,10 +751,8 @@ class FormDisplay
 
     /**
      * Tells whether form validation failed
-     *
-     * @return bool
      */
-    public function hasErrors()
+    public function hasErrors(): bool
     {
         return count($this->errors) > 0;
     }
diff --git a/libraries/classes/Config/Forms/BaseFormList.php b/libraries/classes/Config/Forms/BaseFormList.php
index 131adef238..9ebd04f22b 100644
--- a/libraries/classes/Config/Forms/BaseFormList.php
+++ b/libraries/classes/Config/Forms/BaseFormList.php
@@ -38,10 +38,8 @@ class BaseFormList
 
     /**
      * @param string $name Name
-     *
-     * @return bool
      */
-    public static function isValid($name)
+    public static function isValid($name): bool
     {
         return in_array($name, static::$all);
     }
@@ -86,10 +84,8 @@ class BaseFormList
      * @param bool $allowPartialSave allows for partial form saving
      *                               on failed validation
      * @param bool $checkFormSubmit  whether check for $_POST['submit_save']
-     *
-     * @return bool whether processing was successful
      */
-    public function process($allowPartialSave = true, $checkFormSubmit = true)
+    public function process($allowPartialSave = true, $checkFormSubmit = true): bool
     {
         $ret = true;
         foreach ($this->forms as $form) {
@@ -126,10 +122,8 @@ class BaseFormList
 
     /**
      * Tells whether form validation failed
-     *
-     * @return bool
      */
-    public function hasErrors()
+    public function hasErrors(): bool
     {
         $ret = false;
         foreach ($this->forms as $form) {
diff --git a/libraries/classes/Config/ServerConfigChecks.php b/libraries/classes/Config/ServerConfigChecks.php
index 416ae1a2a4..48b2e07229 100644
--- a/libraries/classes/Config/ServerConfigChecks.php
+++ b/libraries/classes/Config/ServerConfigChecks.php
@@ -557,10 +557,8 @@ class ServerConfigChecks
      * Wrapper around function_exists to allow mock in test
      *
      * @param string $name Function name
-     *
-     * @return bool
      */
-    protected function functionExists($name)
+    protected function functionExists($name): bool
     {
         return function_exists($name);
     }
diff --git a/libraries/classes/Controllers/Database/StructureController.php b/libraries/classes/Controllers/Database/StructureController.php
index 8c9796c606..e5bf52392c 100644
--- a/libraries/classes/Controllers/Database/StructureController.php
+++ b/libraries/classes/Controllers/Database/StructureController.php
@@ -706,10 +706,8 @@ class StructureController extends AbstractController
      *
      * @param array  $db       DB to look into
      * @param string $truename Table name
-     *
-     * @return bool
      */
-    protected function hasTable(array $db, $truename)
+    protected function hasTable(array $db, $truename): bool
     {
         foreach ($db as $dbTable) {
             if (
diff --git a/libraries/classes/Controllers/Table/Structure/SaveController.php b/libraries/classes/Controllers/Table/Structure/SaveController.php
index eff57b74ff..c54314e299 100644
--- a/libraries/classes/Controllers/Table/Structure/SaveController.php
+++ b/libraries/classes/Controllers/Table/Structure/SaveController.php
@@ -80,7 +80,7 @@ final class SaveController extends AbstractController
      *
      * @return bool true if error occurred
      */
-    private function updateColumns()
+    private function updateColumns(): bool
     {
         $err_url = Url::getFromRoute('/table/structure', [
             'db' => $this->db,
@@ -348,10 +348,8 @@ final class SaveController extends AbstractController
      * Verifies if some elements of a column have changed
      *
      * @param int $i column index in the request
-     *
-     * @return bool true if we need to generate ALTER TABLE
      */
-    private function columnNeedsAlterTable($i)
+    private function columnNeedsAlterTable($i): bool
     {
         // these two fields are checkboxes so might not be part of the
         // request; therefore we define them to avoid notices below
@@ -393,11 +391,8 @@ final class SaveController extends AbstractController
      *
      * @param array $adjust_privileges assoc array of old col names mapped to new
      *                                 cols
-     *
-     * @return bool boolean whether at least one column privileges
-     * adjusted
      */
-    private function adjustColumnPrivileges(array $adjust_privileges)
+    private function adjustColumnPrivileges(array $adjust_privileges): bool
     {
         $changed = false;
 
diff --git a/libraries/classes/Core.php b/libraries/classes/Core.php
index e0cfbf3c37..d407ef49a4 100644
--- a/libraries/classes/Core.php
+++ b/libraries/classes/Core.php
@@ -293,8 +293,6 @@ class Core
      * @param string $page      page to check
      * @param array  $allowList allow list to check page against
      * @param bool   $include   whether the page is going to be included
-     *
-     * @return bool whether $page is valid or not (in $allowList or not)
      */
     public static function checkPageValidity(&$page, array $allowList = [], $include = false): bool
     {
@@ -661,9 +659,6 @@ class Core
      * Use only for URLs of external sites.
      *
      * @param string $url URL of external site.
-     *
-     * @return bool True: if domain of $url is allowed domain,
-     * False: otherwise.
      */
     public static function isAllowedDomain(string $url): bool
     {
@@ -763,8 +758,6 @@ class Core
      * recursively check if variable is empty
      *
      * @param mixed $value the variable
-     *
-     * @return bool true if empty
      */
     public static function emptyRecursive($value): bool
     {
@@ -997,10 +990,8 @@ class Core
      *
      * @param string $sqlQuery  The sql query
      * @param string $signature The Signature to check
-     *
-     * @return bool
      */
-    public static function checkSqlQuerySignature($sqlQuery, $signature)
+    public static function checkSqlQuerySignature($sqlQuery, $signature): bool
     {
         global $cfg;
 
diff --git a/libraries/classes/Database/Designer/Common.php b/libraries/classes/Database/Designer/Common.php
index c1b0bb99d3..6631c51c8a 100644
--- a/libraries/classes/Database/Designer/Common.php
+++ b/libraries/classes/Database/Designer/Common.php
@@ -331,10 +331,8 @@ class Common
      * Deletes a given pdf page and its corresponding coordinates
      *
      * @param int $pg page id
-     *
-     * @return bool success/failure
      */
-    public function deletePage($pg)
+    public function deletePage($pg): bool
     {
         $cfgRelation = $this->relation->getRelationsParam();
         if (! $cfgRelation['pdfwork']) {
@@ -405,8 +403,6 @@ class Common
      * If no such exists, returns negative index.
      *
      * @param string $pg name
-     *
-     * @return bool if the page already exists
      */
     public function getPageExists(string $pg): bool
     {
@@ -495,10 +491,8 @@ class Common
      * Saves positions of table(s) of a given pdf page
      *
      * @param int $pg pdf page id
-     *
-     * @return bool success/failure
      */
-    public function saveTablePositions($pg)
+    public function saveTablePositions($pg): bool
     {
         $pageId = $this->dbi->escapeString((string) $pg);
 
@@ -834,10 +828,8 @@ class Common
      *
      * @param string $index setting
      * @param string $value value
-     *
-     * @return bool whether the operation succeeded
      */
-    public function saveSetting($index, $value)
+    public function saveSetting($index, $value): bool
     {
         $cfgRelation = $this->relation->getRelationsParam();
         $success = true;
diff --git a/libraries/classes/DatabaseInterface.php b/libraries/classes/DatabaseInterface.php
index a030afe09e..91fb054221 100644
--- a/libraries/classes/DatabaseInterface.php
+++ b/libraries/classes/DatabaseInterface.php
@@ -1045,8 +1045,6 @@ class DatabaseInterface implements DbalInterface
      * @param string $var   variable name
      * @param string $value value to set
      * @param mixed  $link  mysql link resource|object
-     *
-     * @return bool whether query was a successful
      */
     public function setVariable(
         string $var,
@@ -1062,7 +1060,7 @@ class DatabaseInterface implements DbalInterface
             return true;
         }
 
-        return $this->query('SET ' . $var . ' = ' . $value . ';', $link);
+        return (bool) $this->query('SET ' . $var . ' = ' . $value . ';', $link);
     }
 
     /**
@@ -1791,7 +1789,7 @@ class DatabaseInterface implements DbalInterface
     public function isSuperUser(): bool
     {
         if (SessionCache::has('is_superuser')) {
-            return SessionCache::get('is_superuser');
+            return (bool) SessionCache::get('is_superuser');
         }
 
         if (! $this->isConnected()) {
@@ -1820,7 +1818,7 @@ class DatabaseInterface implements DbalInterface
         global $cfg;
 
         if (SessionCache::has('is_grantuser')) {
-            return SessionCache::get('is_grantuser');
+            return (bool) SessionCache::get('is_grantuser');
         }
 
         if (! $this->isConnected()) {
@@ -1863,7 +1861,7 @@ class DatabaseInterface implements DbalInterface
         global $cfg;
 
         if (SessionCache::has('is_createuser')) {
-            return SessionCache::get('is_createuser');
+            return (bool) SessionCache::get('is_createuser');
         }
 
         if (! $this->isConnected()) {
@@ -2068,8 +2066,6 @@ class DatabaseInterface implements DbalInterface
      *
      * @param object $result database result
      * @param int    $offset offset to seek
-     *
-     * @return bool true on success, false on failure
      */
     public function dataSeek($result, int $offset): bool
     {
@@ -2090,8 +2086,6 @@ class DatabaseInterface implements DbalInterface
      * Check if there are any more query results from a multi query
      *
      * @param int $link link type
-     *
-     * @return bool true or false
      */
     public function moreResults($link = self::CONNECT_USER): bool
     {
@@ -2106,8 +2100,6 @@ class DatabaseInterface implements DbalInterface
      * Prepare next result from multi_query
      *
      * @param int $link link type
-     *
-     * @return bool true or false
      */
     public function nextResult($link = self::CONNECT_USER): bool
     {
diff --git a/libraries/classes/Dbal/DbalInterface.php b/libraries/classes/Dbal/DbalInterface.php
index 9ba255acf7..c426e45ad0 100644
--- a/libraries/classes/Dbal/DbalInterface.php
+++ b/libraries/classes/Dbal/DbalInterface.php
@@ -245,8 +245,6 @@ interface DbalInterface
      * @param string $var   variable name
      * @param string $value value to set
      * @param mixed  $link  mysql link resource|object
-     *
-     * @return bool whether query was a successful
      */
     public function setVariable(string $var, string $value, $link = DatabaseInterface::CONNECT_USER): bool;
 
@@ -476,8 +474,6 @@ interface DbalInterface
 
     /**
      * Checks if current user is superuser
-     *
-     * @return bool Whether user is a superuser
      */
     public function isSuperUser(): bool;
 
@@ -547,8 +543,6 @@ interface DbalInterface
      *
      * @param object $result database result
      * @param int    $offset offset to seek
-     *
-     * @return bool true on success, false on failure
      */
     public function dataSeek($result, int $offset): bool;
 
@@ -563,8 +557,6 @@ interface DbalInterface
      * Check if there are any more query results from a multi query
      *
      * @param int $link link type
-     *
-     * @return bool true or false
      */
     public function moreResults($link = DatabaseInterface::CONNECT_USER): bool;
 
@@ -572,8 +564,6 @@ interface DbalInterface
      * Prepare next result from multi_query
      *
      * @param int $link link type
-     *
-     * @return bool true or false
      */
     public function nextResult($link = DatabaseInterface::CONNECT_USER): bool;
 
diff --git a/libraries/classes/Dbal/DbiExtension.php b/libraries/classes/Dbal/DbiExtension.php
index 9ed06fccbf..909c5f40a1 100644
--- a/libraries/classes/Dbal/DbiExtension.php
+++ b/libraries/classes/Dbal/DbiExtension.php
@@ -34,10 +34,8 @@ interface DbiExtension
      *
      * @param string|DatabaseName $databaseName database name to select
      * @param object              $link         connection object
-     *
-     * @return bool
      */
-    public function selectDb($databaseName, $link);
+    public function selectDb($databaseName, $link): bool;
 
     /**
      * runs a query and returns the result
@@ -86,10 +84,8 @@ interface DbiExtension
      *
      * @param object $result database result
      * @param int    $offset offset to seek
-     *
-     * @return bool true on success, false on failure
      */
-    public function dataSeek($result, $offset);
+    public function dataSeek($result, $offset): bool;
 
     /**
      * Frees memory associated with the result
@@ -102,19 +98,15 @@ interface DbiExtension
      * Check if there are any more query results from a multi query
      *
      * @param object $link the connection object
-     *
-     * @return bool true or false
      */
-    public function moreResults($link);
+    public function moreResults($link): bool;
 
     /**
      * Prepare next result from multi_query
      *
      * @param object $link the connection object
-     *
-     * @return bool true or false
      */
-    public function nextResult($link);
+    public function nextResult($link): bool;
 
     /**
      * Store the result returned from multi query
diff --git a/libraries/classes/Dbal/DbiMysqli.php b/libraries/classes/Dbal/DbiMysqli.php
index 6308df2122..1ce43e7d3c 100644
--- a/libraries/classes/Dbal/DbiMysqli.php
+++ b/libraries/classes/Dbal/DbiMysqli.php
@@ -168,10 +168,8 @@ class DbiMysqli implements DbiExtension
      *
      * @param string|DatabaseName $databaseName database name to select
      * @param mysqli              $link         the mysqli object
-     *
-     * @return bool
      */
-    public function selectDb($databaseName, $link)
+    public function selectDb($databaseName, $link): bool
     {
         return $link->select_db((string) $databaseName);
     }
@@ -203,10 +201,8 @@ class DbiMysqli implements DbiExtension
      *
      * @param mysqli $link  mysqli object
      * @param string $query multi query statement to execute
-     *
-     * @return bool
      */
-    public function realMultiQuery($link, $query)
+    public function realMultiQuery($link, $query): bool
     {
         return $link->multi_query($query);
     }
@@ -258,10 +254,8 @@ class DbiMysqli implements DbiExtension
      *
      * @param mysqli_result $result database result
      * @param int           $offset offset to seek
-     *
-     * @return bool true on success, false on failure
      */
-    public function dataSeek($result, $offset)
+    public function dataSeek($result, $offset): bool
     {
         return $result->data_seek($offset);
     }
@@ -284,10 +278,8 @@ class DbiMysqli implements DbiExtension
      * Check if there are any more query results from a multi query
      *
      * @param mysqli $link the mysqli object
-     *
-     * @return bool true or false
      */
-    public function moreResults($link)
+    public function moreResults($link): bool
     {
         return $link->more_results();
     }
@@ -296,10 +288,8 @@ class DbiMysqli implements DbiExtension
      * Prepare next result from multi_query
      *
      * @param mysqli $link the mysqli object
-     *
-     * @return bool true or false
      */
-    public function nextResult($link)
+    public function nextResult($link): bool
     {
         return $link->next_result();
     }
diff --git a/libraries/classes/Display/Results.php b/libraries/classes/Display/Results.php
index b545ca306c..4501724d78 100644
--- a/libraries/classes/Display/Results.php
+++ b/libraries/classes/Display/Results.php
@@ -695,11 +695,9 @@ class Results
      *
      * @param array $analyzedSqlResults analyzed sql results
      *
-     * @return bool
-     *
      * @access private
      */
-    private function isSelect(array $analyzedSqlResults)
+    private function isSelect(array $analyzedSqlResults): bool
     {
         return ! ($this->properties['is_count']
                 || $this->properties['is_export']
@@ -1880,8 +1878,6 @@ class Results
      * @param string $sortTable                 the table name
      * @param string $nameToUseInSort           the sorting column name
      *
-     * @return bool the column sorted or not
-     *
      * @access private
      */
     private function isInSorted(
@@ -1889,7 +1885,7 @@ class Results
         array $sortExpressionNoDirection,
         $sortTable,
         $nameToUseInSort
-    ) {
+    ): bool {
         $indexInExpression = 0;
 
         foreach ($sortExpressionNoDirection as $index => $clause) {
diff --git a/libraries/classes/Engines/Innodb.php b/libraries/classes/Engines/Innodb.php
index dbfbcdf69e..8e141e278f 100644
--- a/libraries/classes/Engines/Innodb.php
+++ b/libraries/classes/Engines/Innodb.php
@@ -364,10 +364,8 @@ class Innodb extends StorageEngine
      * Verifies if this server supports the innodb_file_per_table feature
      *
      * (do not confuse this with phpMyAdmin's storage engine plugins!)
-     *
-     * @return bool whether this feature is supported or not
      */
-    public function supportsFilePerTable()
+    public function supportsFilePerTable(): bool
     {
         global $dbi;
 
diff --git a/libraries/classes/ErrorHandler.php b/libraries/classes/ErrorHandler.php
index 4dcd8f9bf5..787fdc4466 100644
--- a/libraries/classes/ErrorHandler.php
+++ b/libraries/classes/ErrorHandler.php
@@ -552,8 +552,6 @@ class ErrorHandler
      *      also collected by global error handler.
      * This distinguishes between the actual errors
      *      and user errors raised to warn user.
-     *
-     * @return bool true if there are errors to be "prompted", false otherwise
      */
     public function hasErrorsForPrompt(): bool
     {
diff --git a/libraries/classes/Export.php b/libraries/classes/Export.php
index a6bc7811ec..31196515e0 100644
--- a/libraries/classes/Export.php
+++ b/libraries/classes/Export.php
@@ -101,8 +101,6 @@ class Export
     /**
      * Detect whether gzencode is needed; it might not be needed if
      * the server is already compressing by itself
-     *
-     * @return bool Whether gzencode is needed
      */
     public function gzencodeNeeded(): bool
     {
@@ -128,8 +126,6 @@ class Export
      * $this->dumpBuffer, otherwise it prints them out.
      *
      * @param string $line the insert statement
-     *
-     * @return bool Whether output succeeded
      */
     public function outputHandler(?string $line): bool
     {
diff --git a/libraries/classes/Export/Options.php b/libraries/classes/Export/Options.php
index 789e71af7c..2a103dfbbf 100644
--- a/libraries/classes/Export/Options.php
+++ b/libraries/classes/Export/Options.php
@@ -40,10 +40,8 @@ final class Options
      * Outputs appropriate checked statement for checkbox.
      *
      * @param string $str option name
-     *
-     * @return bool
      */
-    private function checkboxCheck($str)
+    private function checkboxCheck($str): bool
     {
         return isset($GLOBALS['cfg']['Export'][$str])
             && $GLOBALS['cfg']['Export'][$str];
diff --git a/libraries/classes/File.php b/libraries/classes/File.php
index 58f94144ec..2ce7b58802 100644
--- a/libraries/classes/File.php
+++ b/libraries/classes/File.php
@@ -132,8 +132,6 @@ class File
     /**
      * deletes file if it is temporary, usually from a moved upload file
      *
-     * @return bool success
-     *
      * @access public
      */
     public function cleanUp(): bool
@@ -148,8 +146,6 @@ class File
     /**
      * deletes the file
      *
-     * @return bool success
-     *
      * @access public
      */
     public function delete(): bool
@@ -163,8 +159,6 @@ class File
      *
      * @param bool $is_temp sets the temp flag
      *
-     * @return bool File::$_is_temp
-     *
      * @access public
      */
     public function isTemp(?bool $is_temp = null): bool
@@ -263,8 +257,6 @@ class File
      *
      * @param string $name name of file uploaded
      *
-     * @return bool success
-     *
      * @access public
      */
     public function setUploadedFile(string $name): bool
@@ -287,8 +279,6 @@ class File
      * @param string $key       the md5 hash of the column name
      * @param string $rownumber number of row to process
      *
-     * @return bool success
-     *
      * @access public
      */
     public function setUploadedFromTblChangeRequest(
@@ -395,8 +385,6 @@ class File
      * @param string $key       the md5 hash of the column name
      * @param string $rownumber number of row to process
      *
-     * @return bool success
-     *
      * @access public
      */
     public function setSelectedFromTblChangeRequest(
@@ -431,8 +419,6 @@ class File
     /**
      * Checks whether there was any error.
      *
-     * @return bool whether an error occurred or not
-     *
      * @access public
      */
     public function isError(): bool
@@ -447,8 +433,6 @@ class File
      * @param string $key       the md5 hash of the column name
      * @param string $rownumber number of row to process
      *
-     * @return bool success
-     *
      * @access public
      */
     public function checkTblChangeForm(string $key, string $rownumber): bool
@@ -477,8 +461,6 @@ class File
      *
      * @param string $name file name
      *
-     * @return bool success
-     *
      * @access public
      */
     public function setLocalSelectedFile(string $name): bool
@@ -514,8 +496,6 @@ class File
     /**
      * Checks whether file can be read.
      *
-     * @return bool whether the file is readable or not
-     *
      * @access public
      */
     public function isReadable(): bool
@@ -530,8 +510,6 @@ class File
      * before opening it. The FAQ 1.11 explains how to create the "./tmp"
      * directory - if needed
      *
-     * @return bool whether uploaded file is fine or not
-     *
      * @todo move check of $cfg['TempDir'] into Config?
      * @access public
      */
diff --git a/libraries/classes/Gis/GisPolygon.php b/libraries/classes/Gis/GisPolygon.php
index 46f134f301..a9f856bf34 100644
--- a/libraries/classes/Gis/GisPolygon.php
+++ b/libraries/classes/Gis/GisPolygon.php
@@ -425,12 +425,10 @@ class GisPolygon extends GisGeometry
      *
      * @param array $ring array of points forming the ring
      *
-     * @return bool whether a set of points represents an outer ring
-     *
      * @access public
      * @static
      */
-    public static function isOuterRing(array $ring)
+    public static function isOuterRing(array $ring): bool
     {
         // If area is negative then it's in clockwise orientation,
         // i.e. it's an outer ring
@@ -443,12 +441,10 @@ class GisPolygon extends GisGeometry
      * @param array $point   x, y coordinates of the point
      * @param array $polygon array of points forming the ring
      *
-     * @return bool whether a given point is inside a given polygon
-     *
      * @access public
      * @static
      */
-    public static function isPointInsidePolygon(array $point, array $polygon)
+    public static function isPointInsidePolygon(array $point, array $polygon): bool
     {
         // If first point is repeated at the end remove it
         $last = count($polygon) - 1;
diff --git a/libraries/classes/Gis/GisVisualization.php b/libraries/classes/Gis/GisVisualization.php
index 43c3ad76cb..c61edf000f 100644
--- a/libraries/classes/Gis/GisVisualization.php
+++ b/libraries/classes/Gis/GisVisualization.php
@@ -138,10 +138,8 @@ class GisVisualization
 
     /**
      * Check if data has SRID
-     *
-     * @return bool
      */
-    public function hasSrid()
+    public function hasSrid(): bool
     {
         foreach ($this->data as $row) {
             if ($row['srid'] != 0) {
diff --git a/libraries/classes/Git.php b/libraries/classes/Git.php
index 2601082fcb..e4540d3cdd 100644
--- a/libraries/classes/Git.php
+++ b/libraries/classes/Git.php
@@ -92,7 +92,7 @@ class Git
             // Define location using cached value
             $git_location = $_SESSION['git_location'];
 
-            return $_SESSION['is_git_revision'];
+            return (bool) $_SESSION['is_git_revision'];
         }
 
         // find out if there is a .git folder
diff --git a/libraries/classes/Import.php b/libraries/classes/Import.php
index 07e27a5816..85efd517de 100644
--- a/libraries/classes/Import.php
+++ b/libraries/classes/Import.php
@@ -81,8 +81,6 @@ class Import
     /**
      * Checks whether timeout is getting close
      *
-     * @return bool true if timeout is close
-     *
      * @access public
      */
     public function checkTimeout(): bool
diff --git a/libraries/classes/Import/Ajax.php b/libraries/classes/Import/Ajax.php
index 61b808cbec..94383cc735 100644
--- a/libraries/classes/Import/Ajax.php
+++ b/libraries/classes/Import/Ajax.php
@@ -70,9 +70,6 @@ final class Ajax
     /**
      * Checks if PhpMyAdmin\Plugins\Import\Upload\UploadProgress bar extension is
      * available.
-     *
-     * @return bool true if PhpMyAdmin\Plugins\Import\Upload\UploadProgress
-     * extension is available, false if it is not
      */
     public static function progressCheck(): bool
     {
@@ -81,9 +78,6 @@ final class Ajax
 
     /**
      * Checks if PHP 5.4 session upload-progress feature is available.
-     *
-     * @return bool true if PHP 5.4 session upload-progress is available,
-     * false if it is not
      */
     public static function sessionCheck(): bool
     {
diff --git a/libraries/classes/Index.php b/libraries/classes/Index.php
index 2841cd3cf4..13efbb70b7 100644
--- a/libraries/classes/Index.php
+++ b/libraries/classes/Index.php
@@ -227,10 +227,8 @@ class Index
      *
      * @param string $table  table
      * @param string $schema schema
-     *
-     * @return bool whether loading was successful
      */
-    private static function loadIndexes($table, $schema)
+    private static function loadIndexes($table, $schema): bool
     {
         global $dbi;
 
@@ -312,10 +310,8 @@ class Index
      * Returns true if $column indexed in this index
      *
      * @param string $column the column
-     *
-     * @return bool true if $column indexed in this index
      */
-    public function hasColumn($column)
+    public function hasColumn($column): bool
     {
         return isset($this->columns[$column]);
     }
diff --git a/libraries/classes/InsertEdit.php b/libraries/classes/InsertEdit.php
index 72934ff195..68a40b44c0 100644
--- a/libraries/classes/InsertEdit.php
+++ b/libraries/classes/InsertEdit.php
@@ -205,8 +205,6 @@ class InsertEdit
      * @param array  $whereClauseArray array of where clauses
      * @param string $localQuery       query performed
      * @param array  $result           MySQL result handle
-     *
-     * @return bool
      */
     private function showEmptyResultMessageOrSetUniqueCondition(
         array $rows,
@@ -214,7 +212,7 @@ class InsertEdit
         array $whereClauseArray,
         $localQuery,
         array $result
-    ) {
+    ): bool {
         $hasUniqueCondition = false;
 
         // No row returned
@@ -439,10 +437,8 @@ class InsertEdit
       *
       * @param array $column description of column in given table
       * @param array $types  the types to verify
-      *
-      * @return bool whether the column's type if one of the $types
       */
-    public function isColumn(array $column, array $types)
+    public function isColumn(array $column, array $types): bool
     {
         foreach ($types as $oneType) {
             if (mb_stripos($column['Type'], $oneType) === 0) {
diff --git a/libraries/classes/IpAllowDeny.php b/libraries/classes/IpAllowDeny.php
index 9c64befb47..0ec09306e3 100644
--- a/libraries/classes/IpAllowDeny.php
+++ b/libraries/classes/IpAllowDeny.php
@@ -36,11 +36,9 @@ class IpAllowDeny
      * @param string $testRange string of IP range to match
      * @param string $ipToTest  string of IP to test against range
      *
-     * @return bool whether the IP mask matches
-     *
      * @access public
      */
-    public function ipMaskTest($testRange, $ipToTest)
+    public function ipMaskTest($testRange, $ipToTest): bool
     {
         if (
             mb_strpos($testRange, ':') > -1
@@ -72,11 +70,9 @@ class IpAllowDeny
      * @param string $testRange string of IP range to match
      * @param string $ipToTest  string of IP to test against range
      *
-     * @return bool whether the IP mask matches
-     *
      * @access public
      */
-    public function ipv4MaskTest($testRange, $ipToTest)
+    public function ipv4MaskTest($testRange, $ipToTest): bool
     {
         $result = true;
         $match = preg_match(
@@ -144,11 +140,9 @@ class IpAllowDeny
      * @param string $test_range string of IP range to match
      * @param string $ip_to_test string of IP to test against range
      *
-     * @return bool whether the IP mask matches
-     *
      * @access public
      */
-    public function ipv6MaskTest($test_range, $ip_to_test)
+    public function ipv6MaskTest($test_range, $ip_to_test): bool
     {
         $result = true;
 
@@ -240,11 +234,9 @@ class IpAllowDeny
      *
      * @see     Core::getIp()
      *
-     * @return bool Whether rule has matched
-     *
      * @access public
      */
-    public function allow()
+    public function allow(): bool
     {
         return $this->allowDeny('allow');
     }
@@ -254,11 +246,9 @@ class IpAllowDeny
      *
      * @see     Core::getIp()
      *
-     * @return bool Whether rule has matched
-     *
      * @access public
      */
-    public function deny()
+    public function deny(): bool
     {
         return $this->allowDeny('deny');
     }
@@ -270,11 +260,9 @@ class IpAllowDeny
      *
      * @param string $type 'allow' | 'deny' type of rule to match
      *
-     * @return bool   Whether rule has matched
-     *
      * @access public
      */
-    private function allowDeny($type)
+    private function allowDeny($type): bool
     {
         global $cfg;
 
diff --git a/libraries/classes/Language.php b/libraries/classes/Language.php
index cc5e3403a5..49cd698b19 100644
--- a/libraries/classes/Language.php
+++ b/libraries/classes/Language.php
@@ -127,10 +127,8 @@ class Language
 
     /**
      * Checks whether language is currently active.
-     *
-     * @return bool
      */
-    public function isActive()
+    public function isActive(): bool
     {
         return $GLOBALS['lang'] == $this->code;
     }
@@ -139,40 +137,34 @@ class Language
      * Checks whether language matches HTTP header Accept-Language.
      *
      * @param string $header Header content
-     *
-     * @return bool
      */
-    public function matchesAcceptLanguage($header)
+    public function matchesAcceptLanguage($header): bool
     {
         $pattern = '/^('
             . addcslashes($this->regex, '/')
             . ')(;q=[0-9]\\.[0-9])?$/i';
 
-        return preg_match($pattern, $header);
+        return (bool) preg_match($pattern, $header);
     }
 
     /**
      * Checks whether language matches HTTP header User-Agent
      *
      * @param string $header Header content
-     *
-     * @return bool
      */
-    public function matchesUserAgent($header)
+    public function matchesUserAgent($header): bool
     {
         $pattern = '/(\(|\[|;[[:space:]])('
             . addcslashes($this->regex, '/')
             . ')(;|\]|\))/i';
 
-        return preg_match($pattern, $header);
+        return (bool) preg_match($pattern, $header);
     }
 
     /**
      * Checks whether language is RTL
-     *
-     * @return bool
      */
-    public function isRTL()
+    public function isRTL(): bool
     {
         return in_array($this->code, ['ar', 'fa', 'he', 'ur']);
     }
diff --git a/libraries/classes/LanguageManager.php b/libraries/classes/LanguageManager.php
index e03fdb75a7..c5445dd17a 100644
--- a/libraries/classes/LanguageManager.php
+++ b/libraries/classes/LanguageManager.php
@@ -798,10 +798,8 @@ class LanguageManager
 
     /**
      * Checks whether there are some languages available
-     *
-     * @return bool
      */
-    public function hasChoice()
+    public function hasChoice(): bool
     {
         return count($this->availableLanguages()) > 1;
     }
diff --git a/libraries/classes/ListAbstract.php b/libraries/classes/ListAbstract.php
index 63e101f9d5..d8c8fe3dbc 100644
--- a/libraries/classes/ListAbstract.php
+++ b/libraries/classes/ListAbstract.php
@@ -32,10 +32,8 @@ abstract class ListAbstract extends ArrayObject
      * missing at least one item it returns false otherwise true
      *
      * @param mixed[] ...$params params
-     *
-     * @return bool true if all items exists, otherwise false
      */
-    public function exists(...$params)
+    public function exists(...$params): bool
     {
         $this_elements = $this->getArrayCopy();
         foreach ($params as $result) {
diff --git a/libraries/classes/ListDatabase.php b/libraries/classes/ListDatabase.php
index aa8c12b817..ede03e00ce 100644
--- a/libraries/classes/ListDatabase.php
+++ b/libraries/classes/ListDatabase.php
@@ -121,10 +121,8 @@ class ListDatabase extends ListAbstract
 
     /**
      * checks the only_db configuration
-     *
-     * @return bool false if there is no only_db, otherwise true
      */
-    protected function checkOnlyDatabase()
+    protected function checkOnlyDatabase(): bool
     {
         if (
             is_string($GLOBALS['cfg']['Server']['only_db'])
diff --git a/libraries/classes/Message.php b/libraries/classes/Message.php
index 650a3df677..6b9a51ed3e 100644
--- a/libraries/classes/Message.php
+++ b/libraries/classes/Message.php
@@ -359,8 +359,6 @@ class Message implements Stringable
      * and optionally makes this message a success message
      *
      * @param bool $set Whether to make this message of SUCCESS type
-     *
-     * @return bool whether this is a success message or not
      */
     public function isSuccess(bool $set = false): bool
     {
@@ -376,8 +374,6 @@ class Message implements Stringable
      * and optionally makes this message a notice message
      *
      * @param bool $set Whether to make this message of NOTICE type
-     *
-     * @return bool whether this is a notice message or not
      */
     public function isNotice(bool $set = false): bool
     {
@@ -393,8 +389,6 @@ class Message implements Stringable
      * and optionally makes this message an error message
      *
      * @param bool $set Whether to make this message of ERROR type
-     *
-     * @return bool Whether this is an error message or not
      */
     public function isError(bool $set = false): bool
     {
@@ -776,8 +770,6 @@ class Message implements Stringable
      * sets and returns whether the message was displayed or not
      *
      * @param bool $isDisplayed whether to set displayed flag
-     *
-     * @return bool Message::$isDisplayed
      */
     public function isDisplayed(bool $isDisplayed = false): bool
     {
diff --git a/libraries/classes/Navigation/Nodes/Node.php b/libraries/classes/Navigation/Nodes/Node.php
index 1a25adc89c..02a85b6a7d 100644
--- a/libraries/classes/Navigation/Nodes/Node.php
+++ b/libraries/classes/Navigation/Nodes/Node.php
@@ -265,8 +265,6 @@ class Node
      *
      * @param bool $countEmptyContainers Whether to count empty child
      *                                   containers as valid children
-     *
-     * @return bool Whether the node has child nodes
      */
     public function hasChildren($countEmptyContainers = true): bool
     {
@@ -508,10 +506,8 @@ class Node
      * Detemines whether a given database should be hidden according to 'hide_db'
      *
      * @param string $db database name
-     *
-     * @return bool whether to hide
      */
-    private function isHideDb($db)
+    private function isHideDb($db): bool
     {
         return ! empty($GLOBALS['cfg']['Server']['hide_db'])
             && preg_match('/' . $GLOBALS['cfg']['Server']['hide_db'] . '/', $db);
diff --git a/libraries/classes/Normalization.php b/libraries/classes/Normalization.php
index 04b583639d..4be9daad0d 100644
--- a/libraries/classes/Normalization.php
+++ b/libraries/classes/Normalization.php
@@ -1103,8 +1103,6 @@ class Normalization
      * @param int    $pkCnt      distinct value count for given partial key
      * @param int    $colCnt     distinct value count for given column
      * @param int    $totalRows  total distinct rows count of the table
-     *
-     * @return bool TRUE if $column is dependent on $partialKey, False otherwise
      */
     private function checkPartialDependency(
         $partialKey,
@@ -1113,7 +1111,7 @@ class Normalization
         $pkCnt,
         $colCnt,
         $totalRows
-    ) {
+    ): bool {
         $query = 'SELECT '
             . 'COUNT(DISTINCT ' . $partialKey . ',' . $column . ') as pkColCnt '
             . 'FROM (SELECT * FROM ' . Util::backquote($table)
diff --git a/libraries/classes/Partitioning/Partition.php b/libraries/classes/Partitioning/Partition.php
index e43a97c0e9..f034383fb5 100644
--- a/libraries/classes/Partitioning/Partition.php
+++ b/libraries/classes/Partitioning/Partition.php
@@ -61,10 +61,8 @@ class Partition extends SubPartition
 
     /**
      * Whether there are sub partitions
-     *
-     * @return bool
      */
-    public function hasSubPartitions()
+    public function hasSubPartitions(): bool
     {
         return ! empty($this->subPartitions);
     }
@@ -240,14 +238,12 @@ class Partition extends SubPartition
     /**
      * checks if MySQL server supports partitioning
      *
-     * @return bool
-     *
      * @static
      * @staticvar bool $have_partitioning
      * @staticvar bool $already_checked
      * @access public
      */
-    public static function havePartitioning()
+    public static function havePartitioning(): bool
     {
         global $dbi;
 
diff --git a/libraries/classes/Plugins/Auth/AuthenticationConfig.php b/libraries/classes/Plugins/Auth/AuthenticationConfig.php
index e0d1c3897a..6f64678688 100644
--- a/libraries/classes/Plugins/Auth/AuthenticationConfig.php
+++ b/libraries/classes/Plugins/Auth/AuthenticationConfig.php
@@ -32,7 +32,7 @@ class AuthenticationConfig extends AuthenticationPlugin
      *
      * @return bool always true
      */
-    public function showLoginForm()
+    public function showLoginForm(): bool
     {
         $response = ResponseRenderer::getInstance();
         if ($response->isAjax()) {
@@ -54,7 +54,7 @@ class AuthenticationConfig extends AuthenticationPlugin
      *
      * @return bool always true
      */
-    public function readCredentials()
+    public function readCredentials(): bool
     {
         if ($GLOBALS['token_provided'] && $GLOBALS['token_mismatch']) {
             return false;
diff --git a/libraries/classes/Plugins/Auth/AuthenticationCookie.php b/libraries/classes/Plugins/Auth/AuthenticationCookie.php
index 8b25502e23..237466cb32 100644
--- a/libraries/classes/Plugins/Auth/AuthenticationCookie.php
+++ b/libraries/classes/Plugins/Auth/AuthenticationCookie.php
@@ -90,11 +90,9 @@ class AuthenticationCookie extends AuthenticationPlugin
      *
      * this function MUST exit/quit the application
      *
-     * @return bool|void
-     *
      * @global string $conn_error the last connection error
      */
-    public function showLoginForm()
+    public function showLoginForm(): bool
     {
         global $conn_error, $route;
 
@@ -269,10 +267,8 @@ class AuthenticationCookie extends AuthenticationPlugin
      * it returns true if all seems ok which usually leads to auth_set_user()
      *
      * it directly switches to showFailure() if user inactivity timeout is reached
-     *
-     * @return bool whether we get authentication settings or not
      */
-    public function readCredentials()
+    public function readCredentials(): bool
     {
         global $conn_error;
 
@@ -477,7 +473,7 @@ class AuthenticationCookie extends AuthenticationPlugin
      *
      * @return bool always true
      */
-    public function storeCredentials()
+    public function storeCredentials(): bool
     {
         global $cfg;
 
@@ -510,10 +506,8 @@ class AuthenticationCookie extends AuthenticationPlugin
 
     /**
      * Stores user credentials after successful login.
-     *
-     * @return void|bool
      */
-    public function rememberCredentials()
+    public function rememberCredentials(): void
     {
         global $route;
 
@@ -562,33 +556,30 @@ class AuthenticationCookie extends AuthenticationPlugin
                 exit;
             }
 
-            return false;
+            return;
         }
 
         // Set server cookies if required (once per session) and, in this case,
         // force reload to ensure the client accepts cookies
-        if (! $GLOBALS['from_cookie']) {
+        if ($GLOBALS['from_cookie']) {
+            return;
+        }
 
-            /**
-             * Clear user cache.
-             */
-            Util::clearUserCache();
+        /**
+         * Clear user cache.
+         */
+        Util::clearUserCache();
 
-            ResponseRenderer::getInstance()
-                ->disable();
+        ResponseRenderer::getInstance()->disable();
 
-            Core::sendHeaderLocation(
-                './index.php?route=/' . Url::getCommonRaw($url_params, '&'),
-                true
-            );
-            if (! defined('TESTSUITE')) {
-                exit;
-            }
+        Core::sendHeaderLocation(
+            './index.php?route=/' . Url::getCommonRaw($url_params, '&'),
+            true
+        );
 
-            return false;
+        if (! defined('TESTSUITE')) {
+            exit;
         }
-
-        return true;
     }
 
     /**
diff --git a/libraries/classes/Plugins/Auth/AuthenticationHttp.php b/libraries/classes/Plugins/Auth/AuthenticationHttp.php
index 5e1e74ca5e..201ca65a76 100644
--- a/libraries/classes/Plugins/Auth/AuthenticationHttp.php
+++ b/libraries/classes/Plugins/Auth/AuthenticationHttp.php
@@ -34,7 +34,7 @@ class AuthenticationHttp extends AuthenticationPlugin
      *
      * @return bool always true (no return indeed)
      */
-    public function showLoginForm()
+    public function showLoginForm(): bool
     {
         $response = ResponseRenderer::getInstance();
         if ($response->isAjax()) {
@@ -53,10 +53,8 @@ class AuthenticationHttp extends AuthenticationPlugin
 
     /**
      * Displays authentication form
-     *
-     * @return bool
      */
-    public function authForm()
+    public function authForm(): bool
     {
         if (empty($GLOBALS['cfg']['Server']['auth_http_realm'])) {
             if (empty($GLOBALS['cfg']['Server']['verbose'])) {
@@ -107,10 +105,8 @@ class AuthenticationHttp extends AuthenticationPlugin
 
     /**
      * Gets authentication credentials
-     *
-     * @return bool whether we get authentication settings or not
      */
-    public function readCredentials()
+    public function readCredentials(): bool
     {
         // Grabs the $PHP_AUTH_USER variable
         if (isset($GLOBALS['PHP_AUTH_USER'])) {
diff --git a/libraries/classes/Plugins/Auth/AuthenticationSignon.php b/libraries/classes/Plugins/Auth/AuthenticationSignon.php
index d8f3e6a00e..26a911af1d 100644
--- a/libraries/classes/Plugins/Auth/AuthenticationSignon.php
+++ b/libraries/classes/Plugins/Auth/AuthenticationSignon.php
@@ -37,7 +37,7 @@ class AuthenticationSignon extends AuthenticationPlugin
      *
      * @return bool always true (no return indeed)
      */
-    public function showLoginForm()
+    public function showLoginForm(): bool
     {
         ResponseRenderer::getInstance()->disable();
         unset($_SESSION['LAST_SIGNON_URL']);
@@ -118,10 +118,8 @@ class AuthenticationSignon extends AuthenticationPlugin
 
     /**
      * Gets authentication credentials
-     *
-     * @return bool whether we get authentication settings or not
      */
-    public function readCredentials()
+    public function readCredentials(): bool
     {
         /* Check if we're using same signon server */
         $signon_url = $GLOBALS['cfg']['Server']['SignonURL'];
diff --git a/libraries/classes/Plugins/AuthenticationPlugin.php b/libraries/classes/Plugins/AuthenticationPlugin.php
index 7e216a2126..04426da221 100644
--- a/libraries/classes/Plugins/AuthenticationPlugin.php
+++ b/libraries/classes/Plugins/AuthenticationPlugin.php
@@ -63,24 +63,18 @@ abstract class AuthenticationPlugin
 
     /**
      * Displays authentication form
-     *
-     * @return bool
      */
-    abstract public function showLoginForm();
+    abstract public function showLoginForm(): bool;
 
     /**
      * Gets authentication credentials
-     *
-     * @return bool
      */
-    abstract public function readCredentials();
+    abstract public function readCredentials(): bool;
 
     /**
      * Set the user and password after last checkings if required
-     *
-     * @return bool
      */
-    public function storeCredentials()
+    public function storeCredentials(): bool
     {
         global $cfg;
 
@@ -94,10 +88,8 @@ abstract class AuthenticationPlugin
 
     /**
      * Stores user credentials after successful login.
-     *
-     * @return void
      */
-    public function rememberCredentials()
+    public function rememberCredentials(): void
     {
     }
 
diff --git a/libraries/classes/Plugins/Export/ExportCodegen.php b/libraries/classes/Plugins/Export/ExportCodegen.php
index 3c5cf1e868..37ff26bd67 100644
--- a/libraries/classes/Plugins/Export/ExportCodegen.php
+++ b/libraries/classes/Plugins/Export/ExportCodegen.php
@@ -94,20 +94,16 @@ class ExportCodegen extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         return true;
     }
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -117,10 +113,8 @@ class ExportCodegen extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -129,10 +123,8 @@ class ExportCodegen extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -143,10 +135,8 @@ class ExportCodegen extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -160,8 +150,6 @@ class ExportCodegen extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -170,7 +158,7 @@ class ExportCodegen extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         $format = (int) $GLOBALS['codegen_format'];
 
         if ($format === self::HANDLER_NHIBERNATE_CS) {
diff --git a/libraries/classes/Plugins/Export/ExportCsv.php b/libraries/classes/Plugins/Export/ExportCsv.php
index 8c246cc88d..9834da414b 100644
--- a/libraries/classes/Plugins/Export/ExportCsv.php
+++ b/libraries/classes/Plugins/Export/ExportCsv.php
@@ -105,10 +105,8 @@ class ExportCsv extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         global $what, $csv_terminated, $csv_separator, $csv_enclosed, $csv_escaped;
         //Enable columns names by default for CSV
@@ -167,10 +165,8 @@ class ExportCsv extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -180,10 +176,8 @@ class ExportCsv extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Alias of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -192,10 +186,8 @@ class ExportCsv extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -206,10 +198,8 @@ class ExportCsv extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -223,8 +213,6 @@ class ExportCsv extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -233,7 +221,7 @@ class ExportCsv extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $what, $csv_terminated, $csv_separator, $csv_enclosed, $csv_escaped, $dbi;
 
         $db_alias = $db;
@@ -360,8 +348,6 @@ class ExportCsv extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/ExportHtmlword.php b/libraries/classes/Plugins/Export/ExportHtmlword.php
index 4136221467..a647e62409 100644
--- a/libraries/classes/Plugins/Export/ExportHtmlword.php
+++ b/libraries/classes/Plugins/Export/ExportHtmlword.php
@@ -98,10 +98,8 @@ class ExportHtmlword extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         global $charset;
 
@@ -123,10 +121,8 @@ class ExportHtmlword extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return $this->export->outputHandler('</body></html>');
     }
@@ -136,10 +132,8 @@ class ExportHtmlword extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -154,10 +148,8 @@ class ExportHtmlword extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -168,10 +160,8 @@ class ExportHtmlword extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -185,8 +175,6 @@ class ExportHtmlword extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -195,7 +183,7 @@ class ExportHtmlword extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $what, $dbi;
 
         $db_alias = $db;
@@ -555,8 +543,6 @@ class ExportHtmlword extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -570,7 +556,7 @@ class ExportHtmlword extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
diff --git a/libraries/classes/Plugins/Export/ExportJson.php b/libraries/classes/Plugins/Export/ExportJson.php
index f313e9b658..66159b9197 100644
--- a/libraries/classes/Plugins/Export/ExportJson.php
+++ b/libraries/classes/Plugins/Export/ExportJson.php
@@ -113,10 +113,8 @@ class ExportJson extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         global $crlf;
 
@@ -136,10 +134,8 @@ class ExportJson extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         global $crlf;
 
@@ -151,10 +147,8 @@ class ExportJson extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         global $crlf;
 
@@ -174,10 +168,8 @@ class ExportJson extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -188,10 +180,8 @@ class ExportJson extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -205,8 +195,6 @@ class ExportJson extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -215,7 +203,7 @@ class ExportJson extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -263,8 +251,6 @@ class ExportJson extends ExportPlugin
      *           }
      *        }
      * }|array|null $aliases
-     *
-     * @return bool False on export fail and true on export end success
      */
     protected function doExportForQuery(
         DatabaseInterface $dbi,
@@ -365,8 +351,6 @@ class ExportJson extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/ExportLatex.php b/libraries/classes/Plugins/Export/ExportLatex.php
index 0e46d7ff41..27a9bc5a05 100644
--- a/libraries/classes/Plugins/Export/ExportLatex.php
+++ b/libraries/classes/Plugins/Export/ExportLatex.php
@@ -202,10 +202,8 @@ class ExportLatex extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         global $crlf, $cfg, $dbi;
 
@@ -229,10 +227,8 @@ class ExportLatex extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -242,10 +238,8 @@ class ExportLatex extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -263,10 +257,8 @@ class ExportLatex extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -277,10 +269,8 @@ class ExportLatex extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -294,8 +284,6 @@ class ExportLatex extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -304,7 +292,7 @@ class ExportLatex extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -458,8 +446,6 @@ class ExportLatex extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the seperator for a file
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
@@ -486,8 +472,6 @@ class ExportLatex extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -501,7 +485,7 @@ class ExportLatex extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
diff --git a/libraries/classes/Plugins/Export/ExportMediawiki.php b/libraries/classes/Plugins/Export/ExportMediawiki.php
index a0e38a95a2..2b6b7db736 100644
--- a/libraries/classes/Plugins/Export/ExportMediawiki.php
+++ b/libraries/classes/Plugins/Export/ExportMediawiki.php
@@ -97,20 +97,16 @@ class ExportMediawiki extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         return true;
     }
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -120,10 +116,8 @@ class ExportMediawiki extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Alias of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -132,10 +126,8 @@ class ExportMediawiki extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -146,10 +138,8 @@ class ExportMediawiki extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -174,8 +164,6 @@ class ExportMediawiki extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     Aliases of db/table/columns
-     *
-     * @return bool               Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -189,7 +177,7 @@ class ExportMediawiki extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -276,8 +264,6 @@ class ExportMediawiki extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool             Whether it succeeded
      */
     public function exportData(
         $db,
@@ -286,7 +272,7 @@ class ExportMediawiki extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -363,8 +349,6 @@ class ExportMediawiki extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/ExportOds.php b/libraries/classes/Plugins/Export/ExportOds.php
index 6d9e604ebd..076c47fed1 100644
--- a/libraries/classes/Plugins/Export/ExportOds.php
+++ b/libraries/classes/Plugins/Export/ExportOds.php
@@ -87,10 +87,8 @@ class ExportOds extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $GLOBALS['ods_buffer'] .= '<?xml version="1.0" encoding="utf-8"?' . '>'
             . '<office:document-content '
@@ -143,10 +141,8 @@ class ExportOds extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         $GLOBALS['ods_buffer'] .= '</office:spreadsheet>'
             . '</office:body>'
@@ -165,10 +161,8 @@ class ExportOds extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -177,10 +171,8 @@ class ExportOds extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -191,10 +183,8 @@ class ExportOds extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -208,8 +198,6 @@ class ExportOds extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -218,7 +206,7 @@ class ExportOds extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $what, $dbi;
 
         $db_alias = $db;
@@ -344,8 +332,6 @@ class ExportOds extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/ExportOdt.php b/libraries/classes/Plugins/Export/ExportOdt.php
index b98f088bee..1b1c6f3195 100644
--- a/libraries/classes/Plugins/Export/ExportOdt.php
+++ b/libraries/classes/Plugins/Export/ExportOdt.php
@@ -149,10 +149,8 @@ class ExportOdt extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $GLOBALS['odt_buffer'] .= '<?xml version="1.0" encoding="utf-8"?' . '>'
             . '<office:document-content '
@@ -165,10 +163,8 @@ class ExportOdt extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         $GLOBALS['odt_buffer'] .= '</office:text>'
             . '</office:body>'
@@ -185,10 +181,8 @@ class ExportOdt extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -206,10 +200,8 @@ class ExportOdt extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -220,10 +212,8 @@ class ExportOdt extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -237,8 +227,6 @@ class ExportOdt extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -247,7 +235,7 @@ class ExportOdt extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $what, $dbi;
 
         $db_alias = $db;
@@ -354,8 +342,6 @@ class ExportOdt extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
@@ -446,8 +432,6 @@ class ExportOdt extends ExportPlugin
      *                              the end
      * @param bool   $view          whether we're handling a view
      * @param array  $aliases       Aliases of db/table/columns
-     *
-     * @return bool true
      */
     public function getTableDef(
         $db,
@@ -461,7 +445,7 @@ class ExportOdt extends ExportPlugin
         $add_semicolon = true,
         $view = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $cfgRelation, $dbi;
 
         $db_alias = $db;
@@ -693,8 +677,6 @@ class ExportOdt extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -708,7 +690,7 @@ class ExportOdt extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
diff --git a/libraries/classes/Plugins/Export/ExportPdf.php b/libraries/classes/Plugins/Export/ExportPdf.php
index 424a5696aa..df91281f7c 100644
--- a/libraries/classes/Plugins/Export/ExportPdf.php
+++ b/libraries/classes/Plugins/Export/ExportPdf.php
@@ -107,10 +107,8 @@ class ExportPdf extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $pdf = $this->getPdf();
         $pdf->Open();
@@ -124,10 +122,8 @@ class ExportPdf extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         $pdf = $this->getPdf();
 
@@ -140,10 +136,8 @@ class ExportPdf extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -152,10 +146,8 @@ class ExportPdf extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -166,10 +158,8 @@ class ExportPdf extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -183,8 +173,6 @@ class ExportPdf extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -193,7 +181,7 @@ class ExportPdf extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         $db_alias = $db;
         $table_alias = $table;
         $this->initAlias($aliases, $db_alias, $table_alias);
@@ -215,8 +203,6 @@ class ExportPdf extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
@@ -249,8 +235,6 @@ class ExportPdf extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     aliases for db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -264,7 +248,7 @@ class ExportPdf extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         $db_alias = $db;
         $table_alias = $table;
         $purpose = '';
diff --git a/libraries/classes/Plugins/Export/ExportPhparray.php b/libraries/classes/Plugins/Export/ExportPhparray.php
index 64a739c688..15b17d3301 100644
--- a/libraries/classes/Plugins/Export/ExportPhparray.php
+++ b/libraries/classes/Plugins/Export/ExportPhparray.php
@@ -79,10 +79,8 @@ class ExportPhparray extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $this->export->outputHandler(
             '<?php' . $GLOBALS['crlf']
@@ -97,10 +95,8 @@ class ExportPhparray extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -110,10 +106,8 @@ class ExportPhparray extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -132,10 +126,8 @@ class ExportPhparray extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -146,10 +138,8 @@ class ExportPhparray extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -163,8 +153,6 @@ class ExportPhparray extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -173,7 +161,7 @@ class ExportPhparray extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -274,8 +262,6 @@ class ExportPhparray extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/ExportSql.php b/libraries/classes/Plugins/Export/ExportSql.php
index cb1677d397..dfc91f6ccb 100644
--- a/libraries/classes/Plugins/Export/ExportSql.php
+++ b/libraries/classes/Plugins/Export/ExportSql.php
@@ -601,10 +601,8 @@ class ExportSql extends ExportPlugin
      *
      * @param string $db      Database
      * @param array  $aliases Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportRoutines($db, array $aliases = [])
+    public function exportRoutines($db, array $aliases = []): bool
     {
         global $crlf, $dbi;
 
@@ -706,10 +704,8 @@ class ExportSql extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         global $crlf, $dbi;
 
@@ -746,10 +742,8 @@ class ExportSql extends ExportPlugin
     /**
      * Outputs export header. It is the first method to be called, so all
      * the required variables are initialized here.
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         global $crlf, $cfg, $dbi;
 
@@ -861,10 +855,8 @@ class ExportSql extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         global $crlf, $dbi;
 
@@ -930,10 +922,8 @@ class ExportSql extends ExportPlugin
      *
      * @param string $db     db to use
      * @param string $compat sql compatibility
-     *
-     * @return bool Whether it succeeded
      */
-    private function exportUseStatement($db, $compat)
+    private function exportUseStatement($db, $compat): bool
     {
         global $crlf;
 
@@ -962,10 +952,8 @@ class ExportSql extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Alias of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -995,10 +983,8 @@ class ExportSql extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         global $crlf;
 
@@ -1029,10 +1015,8 @@ class ExportSql extends ExportPlugin
      * Exports events
      *
      * @param string $db Database
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportEvents($db)
+    public function exportEvents($db): bool
     {
         global $crlf, $dbi;
 
@@ -1080,14 +1064,12 @@ class ExportSql extends ExportPlugin
      * @param string       $db            database being exported
      * @param string|array $tables        table(s) being exported
      * @param array        $metadataTypes types of metadata to export
-     *
-     * @return bool Whether it succeeded
      */
     public function exportMetadata(
         $db,
         $tables,
         array $metadataTypes
-    ) {
+    ): bool {
         $cfgRelation = $this->relation->getRelationsParam();
         if (! isset($cfgRelation['db'])) {
             return true;
@@ -1134,14 +1116,12 @@ class ExportSql extends ExportPlugin
      * @param string      $db            database being exported
      * @param string|null $table         table being exported
      * @param array       $metadataTypes types of metadata to export
-     *
-     * @return bool Whether it succeeded
      */
     private function exportConfigurationMetadata(
         $db,
         $table,
         array $metadataTypes
-    ) {
+    ): bool {
         global $dbi;
 
         $cfgRelation = $this->relation->getRelationsParam();
@@ -2139,8 +2119,6 @@ class ExportSql extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the seperator for a file
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
@@ -2167,8 +2145,6 @@ class ExportSql extends ExportPlugin
      * @param bool   $mime       whether to include mime comments
      * @param bool   $dates      whether to include creation/update/check dates
      * @param array  $aliases    Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -2182,7 +2158,7 @@ class ExportSql extends ExportPlugin
         $mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $dbAlias = $db;
@@ -2355,8 +2331,6 @@ class ExportSql extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -2365,7 +2339,7 @@ class ExportSql extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $current_row, $sql_backquotes, $dbi;
 
         // Do not export data for merge tables
diff --git a/libraries/classes/Plugins/Export/ExportTexytext.php b/libraries/classes/Plugins/Export/ExportTexytext.php
index 8ce3a2d864..e0f3a26a7e 100644
--- a/libraries/classes/Plugins/Export/ExportTexytext.php
+++ b/libraries/classes/Plugins/Export/ExportTexytext.php
@@ -97,20 +97,16 @@ class ExportTexytext extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         return true;
     }
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         return true;
     }
@@ -120,10 +116,8 @@ class ExportTexytext extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Alias of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         if (empty($dbAlias)) {
             $dbAlias = $db;
@@ -138,10 +132,8 @@ class ExportTexytext extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -152,10 +144,8 @@ class ExportTexytext extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -169,8 +159,6 @@ class ExportTexytext extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -179,7 +167,7 @@ class ExportTexytext extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $what, $dbi;
 
         $db_alias = $db;
@@ -260,8 +248,6 @@ class ExportTexytext extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
@@ -524,8 +510,6 @@ class ExportTexytext extends ExportPlugin
      * @param bool   $do_mime     whether to include mime comments
      * @param bool   $dates       whether to include creation/update/check dates
      * @param array  $aliases     Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -539,7 +523,7 @@ class ExportTexytext extends ExportPlugin
         $do_mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
diff --git a/libraries/classes/Plugins/Export/ExportXml.php b/libraries/classes/Plugins/Export/ExportXml.php
index 10c60e7f05..15ff0e82ef 100644
--- a/libraries/classes/Plugins/Export/ExportXml.php
+++ b/libraries/classes/Plugins/Export/ExportXml.php
@@ -207,10 +207,8 @@ class ExportXml extends ExportPlugin
     /**
      * Outputs export header. It is the first method to be called, so all
      * the required variables are initialized here.
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $this->initSpecificVariables();
         global $crlf, $cfg, $db, $dbi;
@@ -387,10 +385,8 @@ class ExportXml extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         $foot = '</pma_xml_export>';
 
@@ -402,10 +398,8 @@ class ExportXml extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         global $crlf;
 
@@ -433,10 +427,8 @@ class ExportXml extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         global $crlf;
 
@@ -456,10 +448,8 @@ class ExportXml extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -473,8 +463,6 @@ class ExportXml extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -483,7 +471,7 @@ class ExportXml extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         // Do not export data for merge tables
diff --git a/libraries/classes/Plugins/Export/ExportYaml.php b/libraries/classes/Plugins/Export/ExportYaml.php
index 40165dd342..02eeaa0797 100644
--- a/libraries/classes/Plugins/Export/ExportYaml.php
+++ b/libraries/classes/Plugins/Export/ExportYaml.php
@@ -66,10 +66,8 @@ class ExportYaml extends ExportPlugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportHeader()
+    public function exportHeader(): bool
     {
         $this->export->outputHandler(
             '%YAML 1.1' . $GLOBALS['crlf'] . '---' . $GLOBALS['crlf']
@@ -80,10 +78,8 @@ class ExportYaml extends ExportPlugin
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportFooter()
+    public function exportFooter(): bool
     {
         $this->export->outputHandler('...' . $GLOBALS['crlf']);
 
@@ -95,10 +91,8 @@ class ExportYaml extends ExportPlugin
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBHeader($db, $dbAlias = '')
+    public function exportDBHeader($db, $dbAlias = ''): bool
     {
         return true;
     }
@@ -107,10 +101,8 @@ class ExportYaml extends ExportPlugin
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBFooter($db)
+    public function exportDBFooter($db): bool
     {
         return true;
     }
@@ -121,10 +113,8 @@ class ExportYaml extends ExportPlugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportDBCreate($db, $exportType, $dbAlias = '')
+    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
     {
         return true;
     }
@@ -138,8 +128,6 @@ class ExportYaml extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportData(
         $db,
@@ -148,7 +136,7 @@ class ExportYaml extends ExportPlugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    ) {
+    ): bool {
         global $dbi;
 
         $db_alias = $db;
@@ -236,8 +224,6 @@ class ExportYaml extends ExportPlugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the end of line sequence
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(string $errorUrl, string $sqlQuery, string $crlf): bool
     {
diff --git a/libraries/classes/Plugins/Export/Helpers/Pdf.php b/libraries/classes/Plugins/Export/Helpers/Pdf.php
index 8bc315cb1f..57c51bf618 100644
--- a/libraries/classes/Plugins/Export/Helpers/Pdf.php
+++ b/libraries/classes/Plugins/Export/Helpers/Pdf.php
@@ -140,10 +140,8 @@ class Pdf extends PdfLib
      *                           position
      * @param bool      $addpage if true add a page, otherwise only return
      *                           the true/false state
-     *
-     * @return bool true in case of page break, false otherwise.
      */
-    public function checkPageBreak($h = 0, $y = '', $addpage = true)
+    public function checkPageBreak($h = 0, $y = '', $addpage = true): bool
     {
         if (TCPDF_STATIC::empty_string($y)) {
             $y = $this->y;
diff --git a/libraries/classes/Plugins/Export/Helpers/TableProperty.php b/libraries/classes/Plugins/Export/Helpers/TableProperty.php
index 106ce4f8dd..5866d21704 100644
--- a/libraries/classes/Plugins/Export/Helpers/TableProperty.php
+++ b/libraries/classes/Plugins/Export/Helpers/TableProperty.php
@@ -212,8 +212,6 @@ class TableProperty
 
     /**
      * Tells whether the key is primary or not
-     *
-     * @return bool true if the key is primary, false otherwise
      */
     public function isPK(): bool
     {
diff --git a/libraries/classes/Plugins/ExportPlugin.php b/libraries/classes/Plugins/ExportPlugin.php
index 1eb8670ad0..519b8b6e78 100644
--- a/libraries/classes/Plugins/ExportPlugin.php
+++ b/libraries/classes/Plugins/ExportPlugin.php
@@ -52,36 +52,28 @@ abstract class ExportPlugin implements Plugin
 
     /**
      * Outputs export header
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportHeader();
+    abstract public function exportHeader(): bool;
 
     /**
      * Outputs export footer
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportFooter();
+    abstract public function exportFooter(): bool;
 
     /**
      * Outputs database header
      *
      * @param string $db      Database name
      * @param string $dbAlias Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportDBHeader($db, $dbAlias = '');
+    abstract public function exportDBHeader($db, $dbAlias = ''): bool;
 
     /**
      * Outputs database footer
      *
      * @param string $db Database name
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportDBFooter($db);
+    abstract public function exportDBFooter($db): bool;
 
     /**
      * Outputs CREATE DATABASE statement
@@ -89,10 +81,8 @@ abstract class ExportPlugin implements Plugin
      * @param string $db         Database name
      * @param string $exportType 'server', 'database', 'table'
      * @param string $dbAlias    Aliases of db
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportDBCreate($db, $exportType, $dbAlias = '');
+    abstract public function exportDBCreate($db, $exportType, $dbAlias = ''): bool;
 
     /**
      * Outputs the content of a table
@@ -103,8 +93,6 @@ abstract class ExportPlugin implements Plugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery SQL query for obtaining data
      * @param array  $aliases  Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     abstract public function exportData(
         $db,
@@ -113,7 +101,7 @@ abstract class ExportPlugin implements Plugin
         $errorUrl,
         $sqlQuery,
         array $aliases = []
-    );
+    ): bool;
 
     /**
      * The following methods are used in /export or in /database/operations,
@@ -125,10 +113,8 @@ abstract class ExportPlugin implements Plugin
      *
      * @param string $db      Database
      * @param array  $aliases Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportRoutines($db, array $aliases = [])
+    public function exportRoutines($db, array $aliases = []): bool
     {
         return true;
     }
@@ -137,10 +123,8 @@ abstract class ExportPlugin implements Plugin
      * Exports events
      *
      * @param string $db Database
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportEvents($db)
+    public function exportEvents($db): bool
     {
         return true;
     }
@@ -151,8 +135,6 @@ abstract class ExportPlugin implements Plugin
      * @param string $errorUrl the url to go back in case of error
      * @param string $sqlQuery the rawquery to output
      * @param string $crlf     the seperator for a file
-     *
-     * @return bool if succeeded
      */
     public function exportRawQuery(
         string $errorUrl,
@@ -181,8 +163,6 @@ abstract class ExportPlugin implements Plugin
      * @param bool   $mime       whether to include mime comments
      * @param bool   $dates      whether to include creation/update/check dates
      * @param array  $aliases    Aliases of db/table/columns
-     *
-     * @return bool Whether it succeeded
      */
     public function exportStructure(
         $db,
@@ -196,7 +176,7 @@ abstract class ExportPlugin implements Plugin
         $mime = false,
         $dates = false,
         array $aliases = []
-    ) {
+    ): bool {
         return true;
     }
 
@@ -206,14 +186,12 @@ abstract class ExportPlugin implements Plugin
      * @param string       $db            database being exported
      * @param string|array $tables        table(s) being exported
      * @param array        $metadataTypes types of metadata to export
-     *
-     * @return bool Whether it succeeded
      */
     public function exportMetadata(
         $db,
         $tables,
         array $metadataTypes
-    ) {
+    ): bool {
         return true;
     }
 
diff --git a/libraries/classes/Plugins/IOTransformationsPlugin.php b/libraries/classes/Plugins/IOTransformationsPlugin.php
index 2fd74e1859..36354f1502 100644
--- a/libraries/classes/Plugins/IOTransformationsPlugin.php
+++ b/libraries/classes/Plugins/IOTransformationsPlugin.php
@@ -80,10 +80,8 @@ abstract class IOTransformationsPlugin extends TransformationsPlugin
 
     /**
      * Returns the success status
-     *
-     * @return bool
      */
-    public function isSuccess()
+    public function isSuccess(): bool
     {
         return $this->success;
     }
diff --git a/libraries/classes/Plugins/Import/ImportCsv.php b/libraries/classes/Plugins/Import/ImportCsv.php
index c0a22bd62d..8b346a8492 100644
--- a/libraries/classes/Plugins/Import/ImportCsv.php
+++ b/libraries/classes/Plugins/Import/ImportCsv.php
@@ -944,10 +944,8 @@ class ImportCsv extends AbstractImportCsv
 
     /**
      * Returns true if the table should be analyzed, false otherwise
-     *
-     * @return bool
      */
-    private function getAnalyze()
+    private function getAnalyze(): bool
     {
         return $this->analyze;
     }
diff --git a/libraries/classes/Plugins/Import/ImportMediawiki.php b/libraries/classes/Plugins/Import/ImportMediawiki.php
index 1314da422d..4500a18e0a 100644
--- a/libraries/classes/Plugins/Import/ImportMediawiki.php
+++ b/libraries/classes/Plugins/Import/ImportMediawiki.php
@@ -532,10 +532,8 @@ class ImportMediawiki extends ImportPlugin
 
     /**
      * Returns true if the table should be analyzed, false otherwise
-     *
-     * @return bool
      */
-    private function getAnalyze()
+    private function getAnalyze(): bool
     {
         return $this->analyze;
     }
@@ -579,10 +577,8 @@ class ImportMediawiki extends ImportPlugin
      * Manage $inside_structure_comment
      *
      * @param bool $inside_structure_comment Value to test
-     *
-     * @return bool
      */
-    private function mngInsideStructComm($inside_structure_comment)
+    private function mngInsideStructComm($inside_structure_comment): bool
     {
         // End ignoring structure rows
         if ($inside_structure_comment) {
diff --git a/libraries/classes/Plugins/Schema/ExportRelationSchema.php b/libraries/classes/Plugins/Schema/ExportRelationSchema.php
index 981f1de7ae..2df3c56e2a 100644
--- a/libraries/classes/Plugins/Schema/ExportRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/ExportRelationSchema.php
@@ -103,10 +103,8 @@ class ExportRelationSchema
 
     /**
      * Returns whether to show colors
-     *
-     * @return bool whether to show colors
      */
-    public function isShowColor()
+    public function isShowColor(): bool
     {
         return $this->showColor;
     }
@@ -123,10 +121,8 @@ class ExportRelationSchema
 
     /**
      * Returns whether to show table dimensions
-     *
-     * @return bool whether to show table dimensions
      */
-    public function isTableDimension()
+    public function isTableDimension(): bool
     {
         return $this->tableDimension;
     }
@@ -143,10 +139,8 @@ class ExportRelationSchema
 
     /**
      * Returns whether to use same width for all tables or not
-     *
-     * @return bool whether to use same width for all tables or not
      */
-    public function isAllTableSameWidth()
+    public function isAllTableSameWidth(): bool
     {
         return $this->sameWide;
     }
@@ -165,10 +159,8 @@ class ExportRelationSchema
 
     /**
      * Returns whether to show keys
-     *
-     * @return bool whether to show keys
      */
-    public function isShowKeys()
+    public function isShowKeys(): bool
     {
         return $this->showKeys;
     }
@@ -232,11 +224,9 @@ class ExportRelationSchema
     /**
      * Returns whether the client side database is used
      *
-     * @return bool
-     *
      * @access public
      */
-    public function isOffline()
+    public function isOffline(): bool
     {
         return $this->offline;
     }
diff --git a/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php b/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
index 2c32582e6d..c392ef471d 100644
--- a/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
@@ -282,10 +282,8 @@ class PdfRelationSchema extends ExportRelationSchema
 
     /**
      * Returns whether to show grid
-     *
-     * @return bool whether to show grid
      */
-    public function isShowGrid()
+    public function isShowGrid(): bool
     {
         return $this->showGrid;
     }
@@ -302,10 +300,8 @@ class PdfRelationSchema extends ExportRelationSchema
 
     /**
      * Return whether to show selected database data dictionary or not
-     *
-     * @return bool whether to show selected database data dictionary or not
      */
-    public function isWithDataDictionary()
+    public function isWithDataDictionary(): bool
     {
         return $this->withDoc;
     }
diff --git a/libraries/classes/Plugins/Schema/SchemaDia.php b/libraries/classes/Plugins/Schema/SchemaDia.php
index 6b70a0ec8c..9dfd139874 100644
--- a/libraries/classes/Plugins/Schema/SchemaDia.php
+++ b/libraries/classes/Plugins/Schema/SchemaDia.php
@@ -83,10 +83,8 @@ class SchemaDia extends SchemaPlugin
      * Exports the schema into DIA format.
      *
      * @param string $db database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportSchema($db)
+    public function exportSchema($db): bool
     {
         $export = new DiaRelationSchema($db);
         $export->showOutput();
diff --git a/libraries/classes/Plugins/Schema/SchemaEps.php b/libraries/classes/Plugins/Schema/SchemaEps.php
index 720da6fce1..0770588dc7 100644
--- a/libraries/classes/Plugins/Schema/SchemaEps.php
+++ b/libraries/classes/Plugins/Schema/SchemaEps.php
@@ -84,10 +84,8 @@ class SchemaEps extends SchemaPlugin
      * Exports the schema into EPS format.
      *
      * @param string $db database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportSchema($db)
+    public function exportSchema($db): bool
     {
         $export = new EpsRelationSchema($db);
         $export->showOutput();
diff --git a/libraries/classes/Plugins/Schema/SchemaPdf.php b/libraries/classes/Plugins/Schema/SchemaPdf.php
index 0ab99531c5..d45af9b858 100644
--- a/libraries/classes/Plugins/Schema/SchemaPdf.php
+++ b/libraries/classes/Plugins/Schema/SchemaPdf.php
@@ -118,10 +118,8 @@ class SchemaPdf extends SchemaPlugin
      * Exports the schema into PDF format.
      *
      * @param string $db database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportSchema($db)
+    public function exportSchema($db): bool
     {
         $export = new PdfRelationSchema($db);
         $export->showOutput();
diff --git a/libraries/classes/Plugins/Schema/SchemaSvg.php b/libraries/classes/Plugins/Schema/SchemaSvg.php
index ef6489b1b6..f0ba694a1b 100644
--- a/libraries/classes/Plugins/Schema/SchemaSvg.php
+++ b/libraries/classes/Plugins/Schema/SchemaSvg.php
@@ -71,10 +71,8 @@ class SchemaSvg extends SchemaPlugin
      * Exports the schema into SVG format.
      *
      * @param string $db database name
-     *
-     * @return bool Whether it succeeded
      */
-    public function exportSchema($db)
+    public function exportSchema($db): bool
     {
         $export = new SvgRelationSchema($db);
         $export->showOutput();
diff --git a/libraries/classes/Plugins/SchemaPlugin.php b/libraries/classes/Plugins/SchemaPlugin.php
index 77953236e4..ae3e393e34 100644
--- a/libraries/classes/Plugins/SchemaPlugin.php
+++ b/libraries/classes/Plugins/SchemaPlugin.php
@@ -61,10 +61,8 @@ abstract class SchemaPlugin implements Plugin
      * Exports the schema into the specified format.
      *
      * @param string $db database name
-     *
-     * @return bool Whether it succeeded
      */
-    abstract public function exportSchema($db);
+    abstract public function exportSchema($db): bool;
 
     /**
      * Adds export options common to all plugins.
diff --git a/libraries/classes/Plugins/TwoFactor/Application.php b/libraries/classes/Plugins/TwoFactor/Application.php
index 11687ececb..573df70446 100644
--- a/libraries/classes/Plugins/TwoFactor/Application.php
+++ b/libraries/classes/Plugins/TwoFactor/Application.php
@@ -55,13 +55,11 @@ class Application extends TwoFactorPlugin
     /**
      * Checks authentication, returns true on success
      *
-     * @return bool
-     *
      * @throws IncompatibleWithGoogleAuthenticatorException
      * @throws InvalidCharactersException
      * @throws SecretKeyTooShortException
      */
-    public function check()
+    public function check(): bool
     {
         $this->provided = false;
         if (! isset($_POST['2fa_code'])) {
@@ -70,7 +68,7 @@ class Application extends TwoFactorPlugin
 
         $this->provided = true;
 
-        return $this->google2fa->verifyKey(
+        return (bool) $this->google2fa->verifyKey(
             $this->twofactor->config['settings']['secret'],
             $_POST['2fa_code']
         );
@@ -110,13 +108,11 @@ class Application extends TwoFactorPlugin
     /**
      * Performs backend configuration
      *
-     * @return bool
-     *
      * @throws IncompatibleWithGoogleAuthenticatorException
      * @throws InvalidCharactersException
      * @throws SecretKeyTooShortException
      */
-    public function configure()
+    public function configure(): bool
     {
         if (! isset($_SESSION['2fa_application_key'])) {
             $_SESSION['2fa_application_key'] = $this->google2fa->generateSecretKey();
diff --git a/libraries/classes/Plugins/TwoFactor/Invalid.php b/libraries/classes/Plugins/TwoFactor/Invalid.php
index 5aea4363e0..def3535432 100644
--- a/libraries/classes/Plugins/TwoFactor/Invalid.php
+++ b/libraries/classes/Plugins/TwoFactor/Invalid.php
@@ -22,10 +22,8 @@ class Invalid extends TwoFactorPlugin
 
     /**
      * Checks authentication, returns true on success
-     *
-     * @return bool
      */
-    public function check()
+    public function check(): bool
     {
         return false;
     }
diff --git a/libraries/classes/Plugins/TwoFactor/Key.php b/libraries/classes/Plugins/TwoFactor/Key.php
index 4f46d09948..ae2204e84b 100644
--- a/libraries/classes/Plugins/TwoFactor/Key.php
+++ b/libraries/classes/Plugins/TwoFactor/Key.php
@@ -70,10 +70,8 @@ class Key extends TwoFactorPlugin
 
     /**
      * Checks authentication, returns true on success
-     *
-     * @return bool
      */
-    public function check()
+    public function check(): bool
     {
         $this->provided = false;
         if (! isset($_POST['u2f_authentication_response'], $_SESSION['authenticationRequest'])) {
@@ -164,10 +162,8 @@ class Key extends TwoFactorPlugin
 
     /**
      * Performs backend configuration
-     *
-     * @return bool
      */
-    public function configure()
+    public function configure(): bool
     {
         $this->provided = false;
         if (! isset($_POST['u2f_registration_response'], $_SESSION['registrationRequest'])) {
diff --git a/libraries/classes/Plugins/TwoFactor/Simple.php b/libraries/classes/Plugins/TwoFactor/Simple.php
index f96c4c25b7..0790c2062b 100644
--- a/libraries/classes/Plugins/TwoFactor/Simple.php
+++ b/libraries/classes/Plugins/TwoFactor/Simple.php
@@ -23,10 +23,8 @@ class Simple extends TwoFactorPlugin
 
     /**
      * Checks authentication, returns true on success
-     *
-     * @return bool
      */
-    public function check()
+    public function check(): bool
     {
         return isset($_POST['2fa_confirm']);
     }
diff --git a/libraries/classes/Plugins/TwoFactorPlugin.php b/libraries/classes/Plugins/TwoFactorPlugin.php
index 0b3ab1c767..38f8bcfab2 100644
--- a/libraries/classes/Plugins/TwoFactorPlugin.php
+++ b/libraries/classes/Plugins/TwoFactorPlugin.php
@@ -84,10 +84,8 @@ class TwoFactorPlugin
 
     /**
      * Checks authentication, returns true on success
-     *
-     * @return bool
      */
-    public function check()
+    public function check(): bool
     {
         return true;
     }
@@ -114,10 +112,8 @@ class TwoFactorPlugin
 
     /**
      * Performs backend configuration
-     *
-     * @return bool
      */
-    public function configure()
+    public function configure(): bool
     {
         return true;
     }
diff --git a/libraries/classes/Profiling.php b/libraries/classes/Profiling.php
index 983075f9c0..4ad63cf780 100644
--- a/libraries/classes/Profiling.php
+++ b/libraries/classes/Profiling.php
@@ -16,7 +16,7 @@ final class Profiling
     public static function isSupported(DatabaseInterface $dbi): bool
     {
         if (SessionCache::has('profiling_supported')) {
-            return SessionCache::get('profiling_supported');
+            return (bool) SessionCache::get('profiling_supported');
         }
 
         /**
diff --git a/libraries/classes/RecentFavoriteTable.php b/libraries/classes/RecentFavoriteTable.php
index f16dfcb0fb..f4d38d756c 100644
--- a/libraries/classes/RecentFavoriteTable.php
+++ b/libraries/classes/RecentFavoriteTable.php
@@ -176,8 +176,6 @@ class RecentFavoriteTable
     /**
      * Trim recent.favorite table according to the
      * NumRecentTables/NumFavoriteTables configuration.
-     *
-     * @return bool True if trimming occurred
      */
     public function trim(): bool
     {
diff --git a/libraries/classes/Relation.php b/libraries/classes/Relation.php
index 0869cd9549..5442d4f762 100644
--- a/libraries/classes/Relation.php
+++ b/libraries/classes/Relation.php
@@ -740,8 +740,6 @@ class Relation
      * Check if the table is accessible
      *
      * @param string $tableDbName The table or table.db
-     *
-     * @return bool The table is accessible
      */
     public function canAccessStorageTable(string $tableDbName): bool
     {
@@ -758,11 +756,9 @@ class Relation
      * Check whether column_info table input transformation
      * upgrade is required and try to upgrade silently
      *
-     * @return bool false if upgrade failed
-     *
      * @access public
      */
-    public function tryUpgradeTransformations()
+    public function tryUpgradeTransformations(): bool
     {
         // From 4.3, new input oriented transformation feature was introduced.
         // Check whether column_info table has input transformation columns
@@ -1090,11 +1086,9 @@ class Relation
      * @param string $db      the name of the db
      * @param string $comment the value of the column
      *
-     * @return bool true, if comment-query was made.
-     *
      * @access public
      */
-    public function setDbComment($db, $comment = '')
+    public function setDbComment($db, $comment = ''): bool
     {
         $cfgRelation = $this->getRelationsParam();
 
@@ -1124,7 +1118,7 @@ class Relation
                     AND `column_name` = \'(db_comment)\'';
         }
 
-        return $this->queryAsControlUser($upd_query);
+        return (bool) $this->queryAsControlUser($upd_query);
     }
 
     /**
@@ -2309,10 +2303,8 @@ class Relation
 
     /**
      * Verifies if all the pmadb tables are defined
-     *
-     * @return bool
      */
-    public function arePmadbTablesDefined()
+    public function arePmadbTablesDefined(): bool
     {
         return ! (empty($GLOBALS['cfg']['Server']['bookmarktable'])
             || empty($GLOBALS['cfg']['Server']['relation'])
diff --git a/libraries/classes/ResponseRenderer.php b/libraries/classes/ResponseRenderer.php
index 23b24fa542..b4bc8d1739 100644
--- a/libraries/classes/ResponseRenderer.php
+++ b/libraries/classes/ResponseRenderer.php
@@ -442,10 +442,8 @@ class ResponseRenderer
 
     /**
      * Wrapper around PHP's headers_sent() function.
-     *
-     * @return bool
      */
-    public function headersSent()
+    public function headersSent(): bool
     {
         return headers_sent();
     }
@@ -501,7 +499,7 @@ class ResponseRenderer
      *
      * @return bool Whether caller should exit
      */
-    public function loginPage()
+    public function loginPage(): bool
     {
         /* Handle AJAX redirection */
         if ($this->isAjax()) {
diff --git a/libraries/classes/Sanitize.php b/libraries/classes/Sanitize.php
index 4ef98d9bba..03900303af 100644
--- a/libraries/classes/Sanitize.php
+++ b/libraries/classes/Sanitize.php
@@ -40,10 +40,8 @@ class Sanitize
      * @param string $url   URL to check
      * @param bool   $http  Whether to allow http links
      * @param bool   $other Whether to allow ftp and mailto links
-     *
-     * @return bool True if string can be used as link
      */
-    public static function checkLink($url, $http = false, $other = false)
+    public static function checkLink($url, $http = false, $other = false): bool
     {
         $url = strtolower($url);
         $valid_starts = [
diff --git a/libraries/classes/SavedSearches.php b/libraries/classes/SavedSearches.php
index 6f60dc56cb..dc2cbc52b1 100644
--- a/libraries/classes/SavedSearches.php
+++ b/libraries/classes/SavedSearches.php
@@ -271,10 +271,8 @@ class SavedSearches
 
     /**
      * Save the search
-     *
-     * @return bool
      */
-    public function save()
+    public function save(): bool
     {
         global $dbi;
 
@@ -375,10 +373,8 @@ class SavedSearches
 
     /**
      * Delete the search
-     *
-     * @return bool
      */
-    public function delete()
+    public function delete(): bool
     {
         global $dbi;
 
@@ -404,10 +400,8 @@ class SavedSearches
 
     /**
      * Load the current search from an id.
-     *
-     * @return bool Success
      */
-    public function load()
+    public function load(): bool
     {
         global $dbi;
 
diff --git a/libraries/classes/Server/Privileges.php b/libraries/classes/Server/Privileges.php
index 34dff64463..20604be896 100644
--- a/libraries/classes/Server/Privileges.php
+++ b/libraries/classes/Server/Privileges.php
@@ -3657,10 +3657,8 @@ class Privileges
     /**
      * Check if MariaDB's 'simple_password_check'
      * OR 'cracklib_password_check' is ACTIVE
-     *
-     * @return bool if at least one of the plugins is ACTIVE
      */
-    public function checkIfMariaDBPwdCheckPluginActive()
+    public function checkIfMariaDBPwdCheckPluginActive(): bool
     {
         $serverVersion = $this->dbi->getVersion();
         if (! (Compatibility::isMariaDb() && $serverVersion >= 100002)) {
diff --git a/libraries/classes/Server/SysInfo/Base.php b/libraries/classes/Server/SysInfo/Base.php
index 7da577cd86..771a62c1fa 100644
--- a/libraries/classes/Server/SysInfo/Base.php
+++ b/libraries/classes/Server/SysInfo/Base.php
@@ -40,10 +40,8 @@ class Base
 
     /**
      * Checks whether class is supported in this environment
-     *
-     * @return bool true on success
      */
-    public function supported()
+    public function supported(): bool
     {
         return true;
     }
diff --git a/libraries/classes/Server/SysInfo/Linux.php b/libraries/classes/Server/SysInfo/Linux.php
index d3a0f09369..05a1ae2781 100644
--- a/libraries/classes/Server/SysInfo/Linux.php
+++ b/libraries/classes/Server/SysInfo/Linux.php
@@ -65,10 +65,8 @@ class Linux extends Base
 
     /**
      * Checks whether class is supported in this environment
-     *
-     * @return bool true on success
      */
-    public function supported()
+    public function supported(): bool
     {
         return @is_readable('/proc/meminfo') && @is_readable('/proc/stat');
     }
diff --git a/libraries/classes/Server/SysInfo/SunOs.php b/libraries/classes/Server/SysInfo/SunOs.php
index d6b052c83a..a89823e657 100644
--- a/libraries/classes/Server/SysInfo/SunOs.php
+++ b/libraries/classes/Server/SysInfo/SunOs.php
@@ -56,10 +56,8 @@ class SunOs extends Base
 
     /**
      * Checks whether class is supported in this environment
-     *
-     * @return bool true on success
      */
-    public function supported()
+    public function supported(): bool
     {
         return @is_readable('/proc/meminfo');
     }
diff --git a/libraries/classes/Server/SysInfo/WindowsNt.php b/libraries/classes/Server/SysInfo/WindowsNt.php
index 0143e4a6f5..621d694d01 100644
--- a/libraries/classes/Server/SysInfo/WindowsNt.php
+++ b/libraries/classes/Server/SysInfo/WindowsNt.php
@@ -63,10 +63,8 @@ class WindowsNt extends Base
 
     /**
      * Checks whether class is supported in this environment
-     *
-     * @return bool true on success
      */
-    public function supported()
+    public function supported(): bool
     {
         return $this->wmi !== null;
     }
diff --git a/libraries/classes/Setup/ConfigGenerator.php b/libraries/classes/Setup/ConfigGenerator.php
index 3cbb3100a5..d252636efa 100644
--- a/libraries/classes/Setup/ConfigGenerator.php
+++ b/libraries/classes/Setup/ConfigGenerator.php
@@ -120,10 +120,8 @@ class ConfigGenerator
      * Check whether $array is a continuous 0-based array
      *
      * @param array $array Array to check
-     *
-     * @return bool
      */
-    private static function isZeroBasedArray(array $array)
+    private static function isZeroBasedArray(array $array): bool
     {
         for ($i = 0, $nb = count($array); $i < $nb; $i++) {
             if (! isset($array[$i])) {
diff --git a/libraries/classes/Sql.php b/libraries/classes/Sql.php
index 5b1ca34f20..96e7b66b42 100644
--- a/libraries/classes/Sql.php
+++ b/libraries/classes/Sql.php
@@ -149,10 +149,8 @@ class Sql
      * Verify whether the result set has columns from just one table
      *
      * @param array $fieldsMeta meta fields
-     *
-     * @return bool whether the result set has columns from just one table
      */
-    private function resultSetHasJustOneTable(array $fieldsMeta)
+    private function resultSetHasJustOneTable(array $fieldsMeta): bool
     {
         $justOneTable = true;
         $prevTable = '';
@@ -182,10 +180,8 @@ class Sql
      * @param string $db         database name
      * @param string $table      table name
      * @param array  $fieldsMeta meta fields
-     *
-     * @return bool whether the result set contains a unique key
      */
-    private function resultSetContainsUniqueKey(string $db, string $table, array $fieldsMeta)
+    private function resultSetContainsUniqueKey(string $db, string $table, array $fieldsMeta): bool
     {
         $columns = $this->dbi->getColumns($db, $table);
         $resultSetColumnNames = [];
@@ -360,10 +356,8 @@ class Sql
      *
      * @param array $analyzedSqlResults the analyzed query and other variables set
      *                                    after analyzing the query
-     *
-     * @return bool
      */
-    private function isRememberSortingOrder(array $analyzedSqlResults)
+    private function isRememberSortingOrder(array $analyzedSqlResults): bool
     {
         return isset($analyzedSqlResults['select_expr'], $analyzedSqlResults['select_tables'])
             && $GLOBALS['cfg']['RememberSorting']
@@ -383,10 +377,8 @@ class Sql
      *
      * @param array $analyzedSqlResults the analyzed query and other variables set
      *                                    after analyzing the query
-     *
-     * @return bool
      */
-    private function isAppendLimitClause(array $analyzedSqlResults)
+    private function isAppendLimitClause(array $analyzedSqlResults): bool
     {
         // Assigning LIMIT clause to an syntactically-wrong query
         // is not needed. Also we would want to show the true query
@@ -432,10 +424,8 @@ class Sql
      *
      * @param array $analyzedSqlResults the analyzed query and other variables set
      *                                    after analyzing the query
-     *
-     * @return bool
      */
-    private function isDeleteTransformationInfo(array $analyzedSqlResults)
+    private function isDeleteTransformationInfo(array $analyzedSqlResults): bool
     {
         return ! empty($analyzedSqlResults['querytype'])
             && (($analyzedSqlResults['querytype'] === 'ALTER')
@@ -449,14 +439,12 @@ class Sql
      *                                       after analyzing the query
      * @param bool  $allowUserDropDatabase whether the user is allowed to drop db
      * @param bool  $isSuperUser           whether this user is a superuser
-     *
-     * @return bool
      */
     public function hasNoRightsToDropDatabase(
         array $analyzedSqlResults,
         $allowUserDropDatabase,
         $isSuperUser
-    ) {
+    ): bool {
         return ! $allowUserDropDatabase
             && isset($analyzedSqlResults['drop_database'])
             && $analyzedSqlResults['drop_database']
diff --git a/libraries/classes/StorageEngine.php b/libraries/classes/StorageEngine.php
index dcc1198f14..994bb82f22 100644
--- a/libraries/classes/StorageEngine.php
+++ b/libraries/classes/StorageEngine.php
@@ -139,8 +139,6 @@ class StorageEngine
      * This is public to be used in the StructureComtroller, the first release
      * of this function was looking Mroonga in the engines list but this second
      *  method checks too that mroonga is installed successfully
-     *
-     * @return bool true when the mroonga_command is found
      */
     public static function hasMroongaEngine(): bool
     {
@@ -148,7 +146,7 @@ class StorageEngine
         $cacheKey = 'storage-engine.mroonga.has.mroonga_command';
 
         if (Cache::has($cacheKey)) {
-            return Cache::get($cacheKey, false);
+            return (bool) Cache::get($cacheKey, false);
         }
 
         $supportsMroonga = $dbi->tryQuery('SELECT mroonga_command(\'object_list\');') !== false;
@@ -307,11 +305,9 @@ class StorageEngine
      *
      * @param string $engine name of engine
      *
-     * @return bool whether $engine is valid or not
-     *
      * @static
      */
-    public static function isValid($engine)
+    public static function isValid($engine): bool
     {
         if ($engine === 'PBMS') {
             return true;
diff --git a/libraries/classes/Table.php b/libraries/classes/Table.php
index bb4b24af4c..63cd41f78f 100644
--- a/libraries/classes/Table.php
+++ b/libraries/classes/Table.php
@@ -203,11 +203,8 @@ class Table implements Stringable
      *
      * @param array|string $engine Checks the table engine against an
      *                             array of engine strings or a single string, should be uppercase
-     *
-     * @return bool True, if $engine matches the storage engine for the table,
-     * False otherwise.
      */
-    public function isEngine($engine)
+    public function isEngine($engine): bool
     {
         $tableStorageEngine = $this->getStorageEngine();
 
@@ -226,10 +223,8 @@ class Table implements Stringable
 
     /**
      * returns whether the table is actually a view
-     *
-     * @return bool whether the given is a view
      */
-    public function isView()
+    public function isView(): bool
     {
         $db = $this->dbName;
         $table = $this->name;
@@ -265,10 +260,8 @@ class Table implements Stringable
 
     /**
      * Returns whether the table is actually an updatable view
-     *
-     * @return bool whether the given is an updatable view
      */
-    public function isUpdatableView()
+    public function isUpdatableView(): bool
     {
         if (empty($this->dbName) || empty($this->name)) {
             return false;
@@ -290,10 +283,8 @@ class Table implements Stringable
      *
      * If the ENGINE of the table is MERGE or MRG_MYISAM (alias),
      * this is a merge table.
-     *
-     * @return bool true if it is a merge table
      */
-    public function isMerge()
+    public function isMerge(): bool
     {
         return $this->isEngine(['MERGE', 'MRG_MYISAM']);
     }
@@ -702,10 +693,8 @@ class Table implements Stringable
      * $min_records
      *
      * @param int $minRecords Number of records to check for in a table
-     *
-     * @return bool True, if at least $min_records exist, False otherwise.
      */
-    public function checkIfMinRecordsExist($minRecords = 0)
+    public function checkIfMinRecordsExist($minRecords = 0): bool
     {
         $checkQuery = 'SELECT ';
 
@@ -1004,8 +993,6 @@ class Table implements Stringable
      * @param string      $what        what to be moved or copied (data, dataonly)
      * @param bool        $move        whether to move
      * @param string      $mode        mode
-     *
-     * @return bool true if success, false otherwise
      */
     public static function moveCopy(
         $sourceDb,
@@ -1016,7 +1003,7 @@ class Table implements Stringable
         $move,
         $mode,
         bool $addDropIfExists
-    ) {
+    ): bool {
         global $errorUrl, $dbi;
 
         $relation = new Relation($dbi);
@@ -1561,11 +1548,9 @@ class Table implements Stringable
      * @param string $tableName    name to check
      * @param bool   $isBackquoted whether this name is used inside backquotes or not
      *
-     * @return bool whether the string is valid or not
-     *
      * @todo add check for valid chars in filename on current system/os
      */
-    public static function isValidName($tableName, $isBackquoted = false)
+    public static function isValidName($tableName, $isBackquoted = false): bool
     {
         if ($tableName !== rtrim((string) $tableName)) {
             // trailing spaces not allowed even in backquotes
@@ -1597,10 +1582,8 @@ class Table implements Stringable
      *
      * @param string $newName new table name
      * @param string $newDb   new database name
-     *
-     * @return bool success
      */
-    public function rename($newName, $newDb = null)
+    public function rename($newName, $newDb = null): bool
     {
         if ($this->dbi->getLowerCaseNames() === '1') {
             $newName = strtolower($newName);
@@ -2363,10 +2346,8 @@ class Table implements Stringable
      *
      * @param string $displayField display field
      * @param array  $cfgRelation  configuration relation
-     *
-     * @return bool True on update succeed or False on failure
      */
-    public function updateDisplayField($displayField, array $cfgRelation)
+    public function updateDisplayField($displayField, array $cfgRelation): bool
     {
         if ($displayField == '') {
             $updQuery = 'DELETE FROM '
@@ -2403,8 +2384,6 @@ class Table implements Stringable
      * @param array      $destinationColumn    destination columns
      * @param array      $cfgRelation          configuration relation
      * @param array|null $existrel             db, table, column
-     *
-     * @return bool
      */
     public function updateInternalRelations(
         array $multiEditColumnsName,
@@ -2413,7 +2392,7 @@ class Table implements Stringable
         array $destinationColumn,
         array $cfgRelation,
         $existrel
-    ) {
+    ): bool {
         $updated = false;
         foreach ($destinationDb as $masterFieldMd5 => $foreignDb) {
             $updQuery = null;
diff --git a/libraries/classes/Theme.php b/libraries/classes/Theme.php
index 33769a3a9d..fd4647ae9c 100644
--- a/libraries/classes/Theme.php
+++ b/libraries/classes/Theme.php
@@ -106,11 +106,9 @@ class Theme
     /**
      * Loads theme information
      *
-     * @return bool whether loading them info was successful or not
-     *
      * @access public
      */
-    public function loadInfo()
+    public function loadInfo(): bool
     {
         $infofile = $this->getFsPath() . 'theme.json';
         if (! @file_exists($infofile)) {
@@ -183,11 +181,9 @@ class Theme
     /**
      * checks image path for existence - if not found use img from fallback theme
      *
-     * @return bool
-     *
      * @access public
      */
-    public function checkImgPath()
+    public function checkImgPath(): bool
     {
         // try current theme first
         if (is_dir($this->getFsPath() . 'img' . DIRECTORY_SEPARATOR)) {
@@ -295,11 +291,9 @@ class Theme
      *
      * @param string $version version to compare to
      *
-     * @return bool true if theme version is equal or higher to $version
-     *
      * @access public
      */
-    public function checkVersion($version)
+    public function checkVersion($version): bool
     {
         return version_compare($this->getVersion(), $version, 'lt');
     }
diff --git a/libraries/classes/ThemeManager.php b/libraries/classes/ThemeManager.php
index 26316ca168..bf791ffbe1 100644
--- a/libraries/classes/ThemeManager.php
+++ b/libraries/classes/ThemeManager.php
@@ -140,8 +140,6 @@ class ThemeManager
      *
      * @param string|null $theme theme name
      *
-     * @return bool true on success
-     *
      * @access public
      */
     public function setActiveTheme(?string $theme): bool
diff --git a/libraries/classes/Tracker.php b/libraries/classes/Tracker.php
index e88079307a..c1f4ec3970 100644
--- a/libraries/classes/Tracker.php
+++ b/libraries/classes/Tracker.php
@@ -62,11 +62,9 @@ class Tracker
     /**
      * Gets the on/off value of the Tracker module, starts initialization.
      *
-     * @return bool (true=on|false=off)
-     *
      * @static
      */
-    public static function isActive()
+    public static function isActive(): bool
     {
         global $dbi;
 
@@ -126,11 +124,9 @@ class Tracker
      * @param string $dbName    name of database
      * @param string $tableName name of table
      *
-     * @return bool true or false
-     *
      * @static
      */
-    public static function isTracked($dbName, $tableName)
+    public static function isTracked($dbName, $tableName): bool
     {
         global $dbi;
 
@@ -437,8 +433,6 @@ class Tracker
      * @param string       $type      type of data(DDL || DML)
      * @param string|array $newData   the new tracking data
      *
-     * @return bool result of change
-     *
      * @static
      */
     public static function changeTrackingData(
@@ -447,7 +441,7 @@ class Tracker
         $version,
         $type,
         $newData
-    ) {
+    ): bool {
         global $dbi;
 
         $relation = new Relation($dbi);
diff --git a/libraries/classes/Transformations.php b/libraries/classes/Transformations.php
index 381e9adee9..fb63d5b03b 100644
--- a/libraries/classes/Transformations.php
+++ b/libraries/classes/Transformations.php
@@ -363,8 +363,6 @@ class Transformations
      * @param bool   $forcedelete        force delete, will erase any existing
      *                                   comments for this column
      *
-     * @return bool true, if comment-query was made.
-     *
      * @access public
      */
     public function setMime(
@@ -377,7 +375,7 @@ class Transformations
         $inputTransform,
         $inputTransformOpts,
         $forcedelete = false
-    ) {
+    ): bool {
         global $dbi;
 
         $relation = new Relation($dbi);
@@ -465,7 +463,7 @@ class Transformations
         }
 
         if (isset($upd_query)) {
-            return $relation->queryAsControlUser($upd_query);
+            return (bool) $relation->queryAsControlUser($upd_query);
         }
 
         return false;
@@ -482,10 +480,8 @@ class Transformations
      * @param string $db     Database name
      * @param string $table  Table name
      * @param string $column Column name
-     *
-     * @return bool State of the query execution
      */
-    public function clear($db, $table = '', $column = '')
+    public function clear($db, $table = '', $column = ''): bool
     {
         global $dbi;
 
@@ -512,6 +508,6 @@ class Transformations
             $delete_sql .= '`db_name` = \'' . $db . '\' ';
         }
 
-        return $dbi->tryQuery($delete_sql);
+        return (bool) $dbi->tryQuery($delete_sql);
     }
 }
diff --git a/libraries/classes/TwoFactor.php b/libraries/classes/TwoFactor.php
index fcf192f3db..4531c37c28 100644
--- a/libraries/classes/TwoFactor.php
+++ b/libraries/classes/TwoFactor.php
@@ -203,10 +203,8 @@ class TwoFactor
      * Checks authentication, returns true on success
      *
      * @param bool $skipSession Skip session cache
-     *
-     * @return bool
      */
-    public function check($skipSession = false)
+    public function check($skipSession = false): bool
     {
         if ($skipSession) {
             return $this->backend->check();
@@ -216,7 +214,7 @@ class TwoFactor
             $_SESSION['two_factor_check'] = $this->backend->check();
         }
 
-        return $_SESSION['two_factor_check'];
+        return (bool) $_SESSION['two_factor_check'];
     }
 
     /**
@@ -256,10 +254,8 @@ class TwoFactor
      * if configuration fails.
      *
      * @param string $name Backend name
-     *
-     * @return bool
      */
-    public function configure($name)
+    public function configure($name): bool
     {
         $this->config = ['backend' => $name];
         if ($name === '') {
diff --git a/libraries/classes/Types.php b/libraries/classes/Types.php
index b1695d7ca1..fb688ac170 100644
--- a/libraries/classes/Types.php
+++ b/libraries/classes/Types.php
@@ -53,10 +53,8 @@ class Types
      * Check whether operator is unary.
      *
      * @param string $op operator name
-     *
-     * @return bool
      */
-    public function isUnaryOperator($op)
+    public function isUnaryOperator($op): bool
     {
         return in_array($op, $this->getUnaryOperators());
     }
diff --git a/libraries/classes/Util.php b/libraries/classes/Util.php
index 0b272623c4..69edc45ff5 100644
--- a/libraries/classes/Util.php
+++ b/libraries/classes/Util.php
@@ -99,8 +99,6 @@ class Util
      * Checks whether configuration value tells to show icons.
      *
      * @param string $value Configuration option name
-     *
-     * @return bool Whether to show icons.
      */
     public static function showIcons($value): bool
     {
@@ -111,8 +109,6 @@ class Util
      * Checks whether configuration value tells to show text.
      *
      * @param string $value Configuration option name
-     *
-     * @return bool Whether to show text.
      */
     public static function showText($value): bool
     {
diff --git a/libraries/classes/Utils/ForeignKey.php b/libraries/classes/Utils/ForeignKey.php
index 531dff3174..632a9c2e26 100644
--- a/libraries/classes/Utils/ForeignKey.php
+++ b/libraries/classes/Utils/ForeignKey.php
@@ -59,8 +59,6 @@ final class ForeignKey
 
     /**
      * Handle foreign key check request
-     *
-     * @return bool Default foreign key checks value
      */
     public static function handleDisableCheckInit(): bool
     {
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 563e97617b..6ce562baec 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -486,16 +486,6 @@ parameters:
 			path: libraries/classes/IpAllowDeny.php
 
 		-
-			message: "#^Method PhpMyAdmin\\\\Language\\:\\:matchesAcceptLanguage\\(\\) should return bool but returns int\\|false\\.$#"
-			count: 1
-			path: libraries/classes/Language.php
-
-		-
-			message: "#^Method PhpMyAdmin\\\\Language\\:\\:matchesUserAgent\\(\\) should return bool but returns int\\|false\\.$#"
-			count: 1
-			path: libraries/classes/Language.php
-
-		-
 			message: "#^Method PhpMyAdmin\\\\LanguageManager\\:\\:availableLocales\\(\\) should return array but returns array\\|false\\.$#"
 			count: 1
 			path: libraries/classes/LanguageManager.php
@@ -826,11 +816,6 @@ parameters:
 			path: libraries/classes/Plugins/Transformations/Output/Text_Plain_Binarytoip.php
 
 		-
-			message: "#^Method PhpMyAdmin\\\\Plugins\\\\TwoFactor\\\\Application\\:\\:check\\(\\) should return bool but returns bool\\|int\\.$#"
-			count: 1
-			path: libraries/classes/Plugins/TwoFactor/Application.php
-
-		-
 			message: "#^Method PhpMyAdmin\\\\Relation\\:\\:checkRelationsParam\\(\\) should return array\\<string\\> but returns array\\<string, bool\\|string\\|null\\>\\.$#"
 			count: 1
 			path: libraries/classes/Relation.php
diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index 9d9a9a178b..67e5d22d67 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -96,10 +96,8 @@
       <code>$bookmark-&gt;query</code>
       <code>$row</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="3">
+    <MixedInferredReturnType occurrences="1">
       <code>array|false</code>
-      <code>bool</code>
-      <code>bool</code>
     </MixedInferredReturnType>
     <MixedOperand occurrences="9">
       <code>Util::backquote($cfgBookmark['db'])</code>
@@ -112,9 +110,7 @@
       <code>Util::backquote($cfgBookmark['table'])</code>
       <code>Util::backquote($id_field)</code>
     </MixedOperand>
-    <MixedReturnStatement occurrences="3">
-      <code>$this-&gt;dbi-&gt;query($query, DatabaseInterface::CONNECT_CONTROL)</code>
-      <code>$this-&gt;dbi-&gt;tryQuery($query, DatabaseInterface::CONNECT_CONTROL)</code>
+    <MixedReturnStatement occurrences="1">
       <code>Cache::get($cacheKey)</code>
     </MixedReturnStatement>
     <PropertyNotSetInConstructor occurrences="5">
@@ -534,19 +530,14 @@
       <code>$val</code>
       <code>$value</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="3">
+    <MixedInferredReturnType occurrences="2">
       <code>?string</code>
-      <code>bool</code>
       <code>string</code>
     </MixedInferredReturnType>
-    <MixedReturnStatement occurrences="3">
+    <MixedReturnStatement occurrences="2">
       <code>$cookie_path</code>
       <code>$temp_dir[$name]</code>
-      <code>$this-&gt;get('is_https')</code>
     </MixedReturnStatement>
-    <NullableReturnStatement occurrences="1">
-      <code>$this-&gt;get('is_https')</code>
-    </NullableReturnStatement>
     <PossiblyInvalidArgument occurrences="2">
       <code>$default_value</code>
       <code>$request</code>
@@ -6424,14 +6415,10 @@
       <code>$value</code>
       <code>$warningsCount</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="10">
+    <MixedInferredReturnType occurrences="6">
       <code>array</code>
       <code>array</code>
       <code>array</code>
-      <code>bool</code>
-      <code>bool</code>
-      <code>bool</code>
-      <code>bool</code>
       <code>int|false</code>
       <code>string</code>
       <code>string|bool</code>
@@ -6467,17 +6454,13 @@
     <MixedPropertyFetch occurrences="1">
       <code>$this-&gt;links[$link]-&gt;warning_count</code>
     </MixedPropertyFetch>
-    <MixedReturnStatement occurrences="12">
+    <MixedReturnStatement occurrences="8">
       <code>$column != null ? array_shift($fields) : $fields</code>
       <code>$tables[$database]</code>
       <code>$tables[mb_strtolower($database)]</code>
       <code>$this-&gt;fetchValue('SELECT LAST_INSERT_ID();', 0, 0, $link)</code>
       <code>$this-&gt;lowerCaseTableNames</code>
-      <code>$this-&gt;query('SET ' . $var . ' = ' . $value . ';', $link)</code>
       <code>$user</code>
-      <code>SessionCache::get('is_createuser')</code>
-      <code>SessionCache::get('is_grantuser')</code>
-      <code>SessionCache::get('is_superuser')</code>
       <code>SessionCache::get('mysql_cur_user')</code>
       <code>reset($columns)</code>
     </MixedReturnStatement>
@@ -6485,10 +6468,7 @@
       <code>$this-&gt;extension-&gt;realMultiQuery($this-&gt;links[$linkIndex], $multiQuery)</code>
       <code>mysqli_result[]|bool</code>
     </MixedReturnTypeCoercion>
-    <NullableReturnStatement occurrences="4">
-      <code>SessionCache::get('is_createuser')</code>
-      <code>SessionCache::get('is_grantuser')</code>
-      <code>SessionCache::get('is_superuser')</code>
+    <NullableReturnStatement occurrences="1">
       <code>SessionCache::get('mysql_cur_user')</code>
     </NullableReturnStatement>
     <PossiblyInvalidArgument occurrences="1">
@@ -8357,9 +8337,8 @@
       <code>$position</code>
       <code>$start</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="3">
+    <MixedInferredReturnType occurrences="2">
       <code>?int</code>
-      <code>bool</code>
       <code>stdClass|null</code>
     </MixedInferredReturnType>
     <MixedOperand occurrences="9">
@@ -8381,8 +8360,7 @@
       <code>$commit_json-&gt;committer-&gt;email</code>
       <code>$commit_json-&gt;committer-&gt;name</code>
     </MixedPropertyFetch>
-    <MixedReturnStatement occurrences="3">
-      <code>$_SESSION['is_git_revision']</code>
+    <MixedReturnStatement occurrences="2">
       <code>$packOffsets[1]</code>
       <code>json_decode((string) $is_found)</code>
     </MixedReturnStatement>
@@ -9237,16 +9215,6 @@
       <code>is_array($rules)</code>
     </TypeDoesNotContainType>
   </file>
-  <file src="libraries/classes/Language.php">
-    <InvalidReturnStatement occurrences="2">
-      <code>preg_match($pattern, $header)</code>
-      <code>preg_match($pattern, $header)</code>
-    </InvalidReturnStatement>
-    <InvalidReturnType occurrences="2">
-      <code>bool</code>
-      <code>bool</code>
-    </InvalidReturnType>
-  </file>
   <file src="libraries/classes/LanguageManager.php">
     <DocblockTypeContradiction occurrences="1">
       <code>self::$instance === null</code>
@@ -10673,10 +10641,6 @@
     <DocblockTypeContradiction occurrences="1">
       <code>$resp == null</code>
     </DocblockTypeContradiction>
-    <ImplementedReturnTypeMismatch occurrences="2">
-      <code>bool|void</code>
-      <code>void|bool</code>
-    </ImplementedReturnTypeMismatch>
     <InvalidScalarArgument occurrences="1">
       <code>Core::getIp()</code>
     </InvalidScalarArgument>
@@ -13549,10 +13513,6 @@
     </InvalidArgument>
   </file>
   <file src="libraries/classes/Plugins/TwoFactor/Application.php">
-    <InvalidReturnStatement occurrences="1"/>
-    <InvalidReturnType occurrences="1">
-      <code>bool</code>
-    </InvalidReturnType>
     <MixedArgument occurrences="3">
       <code>$_POST['2fa_code']</code>
       <code>$secret</code>
@@ -13618,19 +13578,10 @@
     <DocblockTypeContradiction occurrences="1">
       <code>is_array($result)</code>
     </DocblockTypeContradiction>
-    <MixedInferredReturnType occurrences="1">
-      <code>bool</code>
-    </MixedInferredReturnType>
-    <MixedReturnStatement occurrences="1">
-      <code>SessionCache::get('profiling_supported')</code>
-    </MixedReturnStatement>
     <MixedReturnTypeCoercion occurrences="2">
       <code>$result</code>
       <code>array&lt;string, string&gt;|null</code>
     </MixedReturnTypeCoercion>
-    <NullableReturnStatement occurrences="1">
-      <code>SessionCache::get('profiling_supported')</code>
-    </NullableReturnStatement>
   </file>
   <file src="libraries/classes/Properties/Options/OptionsPropertyGroup.php">
     <DocblockTypeContradiction occurrences="1">
@@ -14043,9 +13994,8 @@
       <code>$value</code>
       <code>$value</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="5">
+    <MixedInferredReturnType occurrences="4">
       <code>array|false</code>
-      <code>bool</code>
       <code>string</code>
       <code>string[]</code>
       <code>string|false</code>
@@ -14103,13 +14053,12 @@
       <code>Util::backquote($foreign_table)</code>
       <code>Util::backquote($tableDbName)</code>
     </MixedOperand>
-    <MixedReturnStatement occurrences="6">
+    <MixedReturnStatement occurrences="5">
       <code>$_SESSION['relation'][$GLOBALS['server']]</code>
       <code>$column['COLUMN_NAME']</code>
       <code>$comment</code>
       <code>$foreigners[$column]</code>
       <code>$row['display_field']</code>
-      <code>$this-&gt;queryAsControlUser($upd_query)</code>
     </MixedReturnStatement>
     <MixedReturnTypeCoercion occurrences="2">
       <code>$cfgRelation</code>
@@ -15713,9 +15662,8 @@
       <code>$this-&gt;comment</code>
       <code>$this-&gt;title</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="3">
+    <MixedInferredReturnType occurrences="2">
       <code>array[]</code>
-      <code>bool</code>
       <code>string</code>
     </MixedInferredReturnType>
     <MixedOperand occurrences="4">
@@ -15724,10 +15672,9 @@
       <code>$parsed_size[0]</code>
       <code>$parsed_size[1]</code>
     </MixedOperand>
-    <MixedReturnStatement occurrences="3">
+    <MixedReturnStatement occurrences="2">
       <code>$storage_engines</code>
       <code>$this-&gt;$id()</code>
-      <code>Cache::get($cacheKey, false)</code>
     </MixedReturnStatement>
     <MixedReturnTypeCoercion occurrences="2">
       <code>[$dataLength, $indexLength]</code>
@@ -16744,10 +16691,8 @@
       <code>$test_rs</code>
       <code>$values</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="3">
+    <MixedInferredReturnType occurrences="1">
       <code>array</code>
-      <code>bool</code>
-      <code>bool</code>
     </MixedInferredReturnType>
     <MixedOperand occurrences="12">
       <code>Util::backquote($cfgRelation['column_info'])</code>
@@ -16763,9 +16708,7 @@
       <code>Util::backquote($cfgRelation['db'])</code>
       <code>Util::backquote($cfgRelation['db'])</code>
     </MixedOperand>
-    <MixedReturnStatement occurrences="3">
-      <code>$dbi-&gt;tryQuery($delete_sql)</code>
-      <code>$relation-&gt;queryAsControlUser($upd_query)</code>
+    <MixedReturnStatement occurrences="1">
       <code>$stack</code>
     </MixedReturnStatement>
     <PossiblyNullArgument occurrences="1">
@@ -16796,9 +16739,8 @@
       <code>$result</code>
       <code>$result['type']</code>
     </MixedAssignment>
-    <MixedInferredReturnType occurrences="2">
+    <MixedInferredReturnType occurrences="1">
       <code>array</code>
-      <code>bool</code>
     </MixedInferredReturnType>
     <MixedMethodCall occurrences="6">
       <code>$cls::getDescription()</code>
@@ -16808,8 +16750,7 @@
       <code>new $cls($this)</code>
       <code>new $name($this)</code>
     </MixedMethodCall>
-    <MixedReturnStatement occurrences="2">
-      <code>$_SESSION['two_factor_check']</code>
+    <MixedReturnStatement occurrences="1">
       <code>$result</code>
     </MixedReturnStatement>
     <MoreSpecificReturnType occurrences="1">
diff --git a/test/classes/Stubs/DbiDummy.php b/test/classes/Stubs/DbiDummy.php
index 991f20665f..1db41249d5 100644
--- a/test/classes/Stubs/DbiDummy.php
+++ b/test/classes/Stubs/DbiDummy.php
@@ -116,10 +116,8 @@ class DbiDummy implements DbiExtension
      *
      * @param string|DatabaseName $databaseName name of db to select
      * @param object              $link         mysql link resource
-     *
-     * @return bool
      */
-    public function selectDb($databaseName, $link)
+    public function selectDb($databaseName, $link): bool
     {
         $databaseName = $databaseName instanceof DatabaseName
                         ? $databaseName->getName() : $databaseName;
@@ -326,10 +324,8 @@ class DbiDummy implements DbiExtension
      *
      * @param object $result database result
      * @param int    $offset offset to seek
-     *
-     * @return bool true on success, false on failure
      */
-    public function dataSeek($result, $offset)
+    public function dataSeek($result, $offset): bool
     {
         $query_data = &$this->getQueryData($result);
         if ($offset > count($query_data['result'])) {
@@ -354,10 +350,8 @@ class DbiDummy implements DbiExtension
      * Check if there are any more query results from a multi query
      *
      * @param object $link the connection object
-     *
-     * @return bool false
      */
-    public function moreResults($link)
+    public function moreResults($link): bool
     {
         return false;
     }
@@ -366,10 +360,8 @@ class DbiDummy implements DbiExtension
      * Prepare next result from multi_query
      *
      * @param object $link the connection object
-     *
-     * @return bool false
      */
-    public function nextResult($link)
+    public function nextResult($link): bool
     {
         return false;
     }
diff --git a/test/selenium/TestBase.php b/test/selenium/TestBase.php
index 7faac435e4..c36e93a8d7 100644
--- a/test/selenium/TestBase.php
+++ b/test/selenium/TestBase.php
@@ -730,8 +730,6 @@ abstract class TestBase extends TestCase
 
     /**
      * Check if user is logged in to phpmyadmin
-     *
-     * @return bool Where or not user is logged in
      */
     public function isLoggedIn(): bool
     {
@@ -816,8 +814,6 @@ abstract class TestBase extends TestCase
      *
      * @param string $func Locate using - cssSelector, xpath, tagName, partialLinkText, linkText, name, id, className
      * @param string $arg  Selector
-     *
-     * @return bool Whether or not the element is present
      */
     public function isElementPresent(string $func, string $arg): bool
     {