Always use the newly-saved revision with vary-revision

When vary-revision is set, use a currentRevisionCallback to ensure that
the newly-saved revision will always be used by the parser. This keeps
slave lag from making vary-revision not do its job.

Bug: T78237
Change-Id: I92ec928203a67f1236c3ecf6dd5002f66a75c38c

diff --git a/includes/page/WikiPage.php b/includes/page/WikiPage.php
index 9b98592..a0a3c69 100644 (file)
--- a/includes/page/WikiPage.php
+++ b/includes/page/WikiPage.php
@@ -2029,7 +2029,8 @@ class WikiPage implements Page, IDBAccessObject {
         * Returns a stdClass with source, pst and output members
         *
         * @param Content $content
-        * @param int|null $revid
+        * @param Revision|int|null $revision Revision object. For backwards compatibility, a
+        *        revision ID is also accepted, but this is deprecated.
         * @param User|null $user
         * @param string|null $serialFormat
         * @param bool $useCache Check shared prepared edit cache
@@ -2039,10 +2040,23 @@ class WikiPage implements Page, IDBAccessObject {
         * @since 1.21
         */
        public function prepareContentForEdit(
-               Content $content, $revid = null, User $user = null, $serialFormat = null, $useCache = true
+               Content $content, $revision = null, User $user = null, $serialFormat = null, $useCache = true
        ) {
                global $wgContLang, $wgUser, $wgAjaxEditStash;
 
+               if ( is_object( $revision ) ) {
+                       $revid = $revision->getId();
+               } else {
+                       $revid = $revision;
+                       // This code path is deprecated, and nothing is known to
+                       // use it, so performance here shouldn't be a worry.
+                       if ( $revid !== null ) {
+                               $revision = Revision::newFromId( $revid, Revision::READ_LATEST );
+                       } else {
+                               $revision = null;
+                       }
+               }
+
                $user = is_null( $user ) ? $wgUser : $user;
                //XXX: check $user->getId() here???
 
@@ -2092,6 +2106,25 @@ class WikiPage implements Page, IDBAccessObject {
                if ( $cachedEdit ) {
                        $edit->output = $cachedEdit->output;
                } else {
+                       if ( $revision ) {
+                               // We get here if vary-revision is set. This means that this page references
+                               // itself (such as via self-transclusion). In this case, we need to make sure
+                               // that any such self-references refer to the newly-saved revision, and not
+                               // to the previous one, which could otherwise happen due to slave lag.
+                               $oldCallback = $edit->popts->setCurrentRevisionCallback(
+                                       function ( $title, $parser = false ) use ( $revision, &$oldCallback ) {
+                                               if ( $title->equals( $revision->getTitle() ) ) {
+                                                       return $revision;
+                                               } else {
+                                                       return call_user_func(
+                                                               $oldCallback,
+                                                               $title,
+                                                               $parser
+                                                       );
+                                               }
+                                       }
+                               );
+                       }
                        $edit->output = $edit->pstContent
                                ? $edit->pstContent->getParserOutput( $this->mTitle, $revid, $edit->popts )
                                : null;
@@ -2142,7 +2175,7 @@ class WikiPage implements Page, IDBAccessObject {
                // already pre-save transformed once.
                if ( !$this->mPreparedEdit || $this->mPreparedEdit->output->getFlag( 'vary-revision' ) ) {
                        wfDebug( __METHOD__ . ": No prepared edit or vary-revision is set...\n" );
-                       $editInfo = $this->prepareContentForEdit( $content, $revision->getId(), $user );
+                       $editInfo = $this->prepareContentForEdit( $content, $revision, $user );
                } else {
                        wfDebug( __METHOD__ . ": No vary-revision, using prepared edit...\n" );
                        $editInfo = $this->mPreparedEdit;