[#10211] Fix parser state bug triggered by media sources

Fix state issue with modParser::$_removingUnprocessed and modParser::$_processingUncacheable being triggered by processing of media source properties. May have other triggers as well.

core/docs/changelog.txt

@@ -2,6 +2,7 @@
 This file shows the changes in recent releases of MODX. The most current release is usually the
 development release, and is only shown to give an idea of what's currently in the pipeline.
 
+- [#10211] Fix parser state bug triggered by media sources
 - Fix loading modResource derivatives in class_key dropdown
 - [#9973] Prevent extended user classes being set to modUser
 - Upgrade xPDO to 2.2.9-pl

core/model/modx/modparser.class.php

@@ -212,6 +212,9 @@ public function collectElementTags($origContent, array &$matches, $prefix= '[[',
      * @return int The number of processed tags
      */
     public function processElementTags($parentTag, & $content, $processUncacheable= false, $removeUnprocessed= false, $prefix= "[[", $suffix= "]]", $tokens= array (), $depth= 0) {
+        $_processingTag = $this->_processingTag;
+        $_processingUncacheable = $this->_processingUncacheable;
+        $_removingUnprocessed = $this->_removingUnprocessed;
         $this->_processingTag = true;
         $this->_processingUncacheable = (boolean) $processUncacheable;
         $this->_removingUnprocessed = (boolean) $removeUnprocessed;
@@ -256,7 +259,10 @@ public function processElementTags($parentTag, & $content, $processUncacheable=
                 $processed+= $this->processElementTags($parentTag, $content, $processUncacheable, $removeUnprocessed, $prefix, $suffix, $tokens, $depth);
             }
         }
-        $this->_processingTag = false;
+
+        $this->_removingUnprocessed = $_removingUnprocessed;
+        $this->_processingUncacheable = $_processingUncacheable;
+        $this->_processingTag = $_processingTag;
         return $processed;
     }