Update to require php 7.4 or 8.0

composer.json

@@ -19,7 +19,7 @@
         }
     ],
     "require": {
-        "php": ">=5.3.3"
+        "php": "^7.4 || ^8.0"
     },
     "require-dev": {
         "mockery/mockery": "~0.9.1",

lib/classes/Swift/Encoder/QpEncoder.php

@@ -153,9 +153,9 @@ protected function initSafeMap()
      * If the first line needs to be shorter, indicate the difference with
      * $firstLineOffset.
      *
-     * @param string $string           to encode
-     * @param int    $firstLineOffset, optional
-     * @param int    $maxLineLength,   optional 0 indicates the default of 76 chars
+     * @param string $string          string to encode
+     * @param int    $firstLineOffset optional
+     * @param int    $maxLineLength   optional, 0 indicates the default of 76 chars
      *
      * @return string
      */

lib/classes/Swift/KeyCache/SimpleKeyCacheInputStream.php

@@ -15,16 +15,22 @@
  */
 class Swift_KeyCache_SimpleKeyCacheInputStream implements Swift_KeyCache_KeyCacheInputStream
 {
-    /** The KeyCache being written to */
+    /**
+     * @var Swift_KeyCache The KeyCache being written to
+     */
     private $_keyCache;
 
-    /** The nsKey of the KeyCache being written to */
+    /**
+     * @var string The nsKey of the KeyCache being written to
+     */
     private $_nsKey;
 
     /** The itemKey of the KeyCache being written to */
     private $_itemKey;
 
-    /** A stream to write through on each write() */
+    /**
+     * @var Swift_InputByteStream|null A stream to write through on each write()
+     */
     private $_writeThrough = null;
 
     /**
@@ -51,18 +57,23 @@ public function setWriteThroughStream(Swift_InputByteStream $is)
      * Writes $bytes to the end of the stream.
      *
      * @param string                $bytes
-     * @param Swift_InputByteStream $is    optional
+     * @param ?Swift_InputByteStream $is
+     *
+     * @throws Swift_IoException
+     *
+     * @return int
      */
     public function write($bytes, Swift_InputByteStream $is = null)
     {
         $this->_keyCache->setString(
             $this->_nsKey, $this->_itemKey, $bytes, Swift_KeyCache::MODE_APPEND
-            );
+        );
+
         if (isset($is)) {
-            $is->write($bytes);
+            return $is->write($bytes);
         }
         if (isset($this->_writeThrough)) {
-            $this->_writeThrough->write($bytes);
+            return $this->_writeThrough->write($bytes);
         }
     }
 

lib/classes/Swift/Mime/ContentEncoder/QpContentEncoderProxy.php

@@ -56,7 +56,9 @@ public function __clone()
     }
 
     /**
-     * {@inheritdoc}
+     * Notify this observer that the entity's charset has changed.
+     *
+     * @param string $charset
      */
     public function charsetChanged($charset)
     {
@@ -65,23 +67,34 @@ public function charsetChanged($charset)
     }
 
     /**
-     * {@inheritdoc}
+     * Encode $in to $out.
+     *
+     * @param Swift_OutputByteStream $os              to read from
+     * @param Swift_InputByteStream  $is              to write to
+     * @param int                    $firstLineOffset
+     * @param int                    $maxLineLength   - 0 indicates the default length for this encoding
      */
     public function encodeByteStream(Swift_OutputByteStream $os, Swift_InputByteStream $is, $firstLineOffset = 0, $maxLineLength = 0)
     {
         $this->getEncoder()->encodeByteStream($os, $is, $firstLineOffset, $maxLineLength);
     }
 
     /**
-     * {@inheritdoc}
+     * @return string
      */
     public function getName()
     {
         return 'quoted-printable';
     }
 
     /**
-     * {@inheritdoc}
+     * Encode a given string to produce an encoded string.
+     *
+     * @param string $string
+     * @param int    $firstLineOffset ignored
+     * @param int    $maxLineLength   - 0 means no wrapping will occur
+     *
+     * @return string
      */
     public function encodeString($string, $firstLineOffset = 0, $maxLineLength = 0)
     {

lib/classes/Swift/Transport/Esmtp/AuthHandler.php

@@ -39,7 +39,7 @@ class Swift_Transport_Esmtp_AuthHandler implements Swift_Transport_EsmtpHandler
     /**
      * The auth mode for authentication.
      *
-     * @var string
+     * @var string|null
      */
     private $_auth_mode;
 
@@ -248,7 +248,7 @@ public function resetState()
      */
     protected function _getAuthenticatorsForAgent()
     {
-        if (!$mode = strtolower($this->_auth_mode)) {
+        if (!$this->_auth_mode || !$mode = strtolower($this->_auth_mode)) {
             return $this->_authenticators;
         }
 

lib/classes/Swift/Transport/EsmtpTransport.php

@@ -134,18 +134,18 @@ public function getTimeout()
     /**
      * Set the encryption type (tls or ssl).
      *
-     * @param string $encryption
+     * @param string|null $encryption
      *
      * @return $this
      */
     public function setEncryption($encryption)
     {
-        $encryption = strtolower($encryption);
-        if ('tls' == $encryption) {
+        $normalizedEncryption = $encryption ? strtolower($encryption) : '';
+        if ('tls' === $normalizedEncryption) {
             $this->_params['protocol'] = 'tcp';
             $this->_params['tls'] = true;
         } else {
-            $this->_params['protocol'] = $encryption;
+            $this->_params['protocol'] = $normalizedEncryption;
             $this->_params['tls'] = false;
         }