Compatibility fixes for PHP 8.1 (#19143)

* Update .travis.yml

* fix php 8.1 deprecation notices

* Revert "run report tests on any PHP version (#18666)"

This reverts commit ec58ab4606cbc6c7f7c3a7aa7f1e9cc5a88e5dfb.

* apply PSR12 code formatting

* fix deprecation notice

* try to fix test

* fix frontcontroller test

* Clearing output buffers with enabled output compression makes problems on some PHP versions

* Set the mysqli error reporting to none, to prevent possible problems on PHP 8.1

7 files changed, 7 insertions, 7 deletions

diff --git a/plugins/CoreAdminHome/Commands/ConfigDelete.php b/plugins/CoreAdminHome/Commands/ConfigDelete.php
index 7d3c5b243e..3e72bdce54 100644
--- a/plugins/CoreAdminHome/Commands/ConfigDelete.php
+++ b/plugins/CoreAdminHome/Commands/ConfigDelete.php
@@ -77,7 +77,7 @@ NOTES:
             'value' => $input->getOption('value'),
         ]);
 
-        $argument = trim($input->getArgument('argument'));
+        $argument = trim($input->getArgument('argument') ?? '');
 
         // Sanity check inputs.
         switch (true) {
diff --git a/plugins/CoreAdminHome/Commands/ConfigGet.php b/plugins/CoreAdminHome/Commands/ConfigGet.php
index f302040728..dea5f37936 100644
--- a/plugins/CoreAdminHome/Commands/ConfigGet.php
+++ b/plugins/CoreAdminHome/Commands/ConfigGet.php
@@ -89,7 +89,7 @@ NOTES:
             $format = self::OUTPUT_FORMAT_DEFAULT;
         }
 
-        $argument = trim($input->getArgument('argument'));
+        $argument = trim($input->getArgument('argument') ?? '');
 
         // If there are multiple arguments, just use the last one.
         $argument = array_slice(explode(' ', $argument), -1)[0];
diff --git a/plugins/Login/PasswordResetter.php b/plugins/Login/PasswordResetter.php
index 7b6a5efa2c..45854f4601 100644
--- a/plugins/Login/PasswordResetter.php
+++ b/plugins/Login/PasswordResetter.php
@@ -281,7 +281,7 @@ class PasswordResetter
             $expiryTimestamp = $this->getDefaultExpiryTime();
         }
 
-        $expiry = strftime('%Y%m%d%H', $expiryTimestamp);
+        $expiry = date('YmdH', $expiryTimestamp);
         $token = $this->generateSecureHash(
             $expiry . $user['login'] . $user['email'] . $user['ts_password_modified'] . $keySuffix,
             $user['password']
diff --git a/plugins/Marketplace/Api/Service.php b/plugins/Marketplace/Api/Service.php
index 2ff2778b72..e9ca597b84 100644
--- a/plugins/Marketplace/Api/Service.php
+++ b/plugins/Marketplace/Api/Service.php
@@ -132,7 +132,7 @@ class Service
 
         $response = $this->download($url);
 
-        $result = json_decode($response, true);
+        $result = json_decode($response ?? '', true);
 
         if (is_null($result)) {
             $message = sprintf('There was an error reading the response from the Marketplace: Please try again later.');
diff --git a/plugins/PrivacyManager/tests/Fixtures/MultipleSitesMultipleVisitsFixture.php b/plugins/PrivacyManager/tests/Fixtures/MultipleSitesMultipleVisitsFixture.php
index 6a58bc5da2..e9b3e5a47c 100644
--- a/plugins/PrivacyManager/tests/Fixtures/MultipleSitesMultipleVisitsFixture.php
+++ b/plugins/PrivacyManager/tests/Fixtures/MultipleSitesMultipleVisitsFixture.php
@@ -478,7 +478,7 @@ class MultipleSitesMultipleVisitsFixture extends Fixture
     private function trackVisit($userId, $referrer, $idGoal = null, $hoursAgo = null)
     {
         $this->initTracker($userId, $hoursAgo);
-        $this->tracker->setUrlReferrer($referrer);
+        $this->tracker->setUrlReferrer($referrer ?? false);
         $this->tracker->setUrl('http://www.helloworld.com/hello/world' . $userId);
         $this->tracker->doTrackPageView('Hello World ');
 
diff --git a/plugins/Referrers/Columns/Base.php b/plugins/Referrers/Columns/Base.php
index 5064972005..a27aa925e2 100644
--- a/plugins/Referrers/Columns/Base.php
+++ b/plugins/Referrers/Columns/Base.php
@@ -633,7 +633,7 @@ abstract class Base extends VisitDimension
     protected function hasReferrerColumnChanged(Visitor $visitor, $information, $infoName)
     {
         $existing = mb_strtolower($visitor->getVisitorColumn($infoName) ?? '');
-        $new = mb_strtolower($information[$infoName]);
+        $new = mb_strtolower($information[$infoName] ?? '');
 
         $result = $existing != $new;
         if ($result) {
diff --git a/plugins/UserLanguage/functions.php b/plugins/UserLanguage/functions.php
index 2188ce6895..5c52cff957 100644
--- a/plugins/UserLanguage/functions.php
+++ b/plugins/UserLanguage/functions.php
@@ -48,7 +48,7 @@ function languageTranslate($label)
  */
 function languageTranslateWithCode($label)
 {
-    $ex = explode('-', $label);
+    $ex = explode('-', $label ?? '');
     $lang = languageTranslate($ex[0]);
 
     if (count($ex) == 2 && $ex[0] != $ex[1]) {