Merge "[MCR] Introduce RevisionRenderer"

diff --combined includes/parser/Parser.php
index 5f80e27,001d312..bd3c32a
--- 1/includes/parser/Parser.php
--- 2/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@@ -1313,7 -1313,6 +1313,7 @@@ class Parser 
         * @private
         *
         * @param string $text The text to parse
 +       * @param-taint $text escapes_html
         * @param bool $isMain Whether this is being called from the main parse() function
         * @param PPFrame|bool $frame A pre-processor frame
         *
@@@ -2693,9 -2692,19 +2693,19 @@@
                                $this->mOutput->setFlag( 'vary-revision-id' );
                                wfDebug( __METHOD__ . ": {{REVISIONID}} used, setting vary-revision-id...\n" );
                                $value = $this->mRevisionId;
-                               if ( !$value && $this->mOptions->getSpeculativeRevIdCallback() ) {
-                                       $value = call_user_func( $this->mOptions->getSpeculativeRevIdCallback() );
-                                       $this->mOutput->setSpeculativeRevIdUsed( $value );
+ 
+                               if ( !$value ) {
+                                       $rev = $this->getRevisionObject();
+                                       if ( $rev ) {
+                                               $value = $rev->getId();
+                                       }
+                               }
+ 
+                               if ( !$value ) {
+                                       $value = $this->mOptions->getSpeculativeRevId();
+                                       if ( $value ) {
+                                               $this->mOutput->setSpeculativeRevIdUsed( $value );
+                                       }
                                }
                                break;
                        case 'revisionday':
@@@ -5751,10 -5760,9 +5761,9 @@@
                if ( !is_null( $this->mRevisionObject ) ) {
                        return $this->mRevisionObject;
                }
-               if ( is_null( $this->mRevisionId ) ) {
-                       return null;
-               }
  
+               // NOTE: try to get the RevisionObject even if mRevisionId is null.
+               // This is useful when parsing revision that has not yet been saved.
                $rev = call_user_func(
                        $this->mOptions->getCurrentRevisionCallback(), $this->getTitle(), $this
                );
@@@ -5762,7 -5770,7 +5771,7 @@@
                # If the parse is for a new revision, then the callback should have
                # already been set to force the object and should match mRevisionId.
                # If not, try to fetch by mRevisionId for sanity.
-               if ( $rev && $rev->getId() != $this->mRevisionId ) {
+               if ( $this->mRevisionId && $rev && $rev->getId() != $this->mRevisionId ) {
                        $rev = Revision::newFromId( $this->mRevisionId );
                }