Fix various PHP 8.1 warnings (#8584)

4 files changed, 11 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 282de1d10..557c48ce0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - Fix bug where some checkboxes could be selected unintentinally (#8565)
 - Fix css styles of the email recipient element while dragging (#8580)
 - Fix PHP 8.1 warnings in the LDAP backend code (#8572)
+- Fix various PHP 8.1 warnings (#8584)
 
 ## Release 1.6-rc
 
diff --git a/program/actions/mail/show.php b/program/actions/mail/show.php
index beedd78fd..9c81aadf1 100644
--- a/program/actions/mail/show.php
+++ b/program/actions/mail/show.php
@@ -763,7 +763,7 @@ class rcmail_action_mail_show extends rcmail_action_mail_index
         else {
             // Check if we have enough memory to handle the message in it
             // #1487424: we need up to 10x more memory than the body
-            if (!rcube_utils::mem_check(strlen(self::$MESSAGE->body) * 10)) {
+            if (isset(self::$MESSAGE->body) && !rcube_utils::mem_check(strlen(self::$MESSAGE->body) * 10)) {
                 $out .= self::part_too_big_message(self::$MESSAGE, 0);
             }
             else {
diff --git a/program/lib/Roundcube/rcube.php b/program/lib/Roundcube/rcube.php
index bc3fd0038..1b4579069 100644
--- a/program/lib/Roundcube/rcube.php
+++ b/program/lib/Roundcube/rcube.php
@@ -605,7 +605,11 @@ class rcube
         // replace vars in text
         if (!empty($attrib['vars']) && is_array($attrib['vars'])) {
             foreach ($attrib['vars'] as $var_key => $var_value) {
-                $text = str_replace($var_key[0] != '$' ? '$'.$var_key : $var_key, $var_value, $text);
+                if ($var_key[0] != '$') {
+                    $var_key = '$' . $var_key;
+                }
+
+                $text = str_replace($var_key, $var_value ?? '', $text);
             }
         }
 
diff --git a/program/lib/Roundcube/rcube_string_replacer.php b/program/lib/Roundcube/rcube_string_replacer.php
index cbbffcd55..b1b7fcb9e 100644
--- a/program/lib/Roundcube/rcube_string_replacer.php
+++ b/program/lib/Roundcube/rcube_string_replacer.php
@@ -221,6 +221,10 @@ class rcube_string_replacer
      */
     public function replace($str)
     {
+        if (!is_string($str)) {
+            return '';
+        }
+
         // search for patterns like links and e-mail addresses
         $str = preg_replace_callback($this->link_pattern, [$this, 'link_callback'], $str);
         $str = preg_replace_callback($this->mailto_pattern, [$this, 'mailto_callback'], $str);