From a14da4533692780e421781129a3c1005cdb023d3 Mon Sep 17 00:00:00 2001
From: Sam Reed <reedy@users.mediawiki.org>
Date: Sun, 24 Oct 2010 19:16:46 +0000
Subject: [PATCH] * If a action=parse request provides an oldid that is
 actually the current revision id, try the parser cache, and save it to it if
 necessary

---
 RELEASE-NOTES             |  2 ++
 includes/api/ApiParse.php | 31 ++++++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index c8e82098e8..a48505045f 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -444,6 +444,8 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
 * Added iiprop=parsedcomment to prop=imageinfo, similar to prop=revisions
 * Added rvparse to parse revisions. For performance reasons if this option is 
   used, rvlimit is enforced to 1.
+* If a action=parse request provides an oldid that is actually the current revision
+  id, try the parser cache, and save it to it if necessary
 
 === Languages updated in 1.17 ===
 
diff --git a/includes/api/ApiParse.php b/includes/api/ApiParse.php
index c487ca855f..de3b371e80 100644
--- a/includes/api/ApiParse.php
+++ b/includes/api/ApiParse.php
@@ -89,15 +89,36 @@ class ApiParse extends ApiBase {
 					$this->dieUsage( "You don't have permission to view deleted revisions", 'permissiondenied' );
 				}
 
-				$text = $rev->getText( Revision::FOR_THIS_USER );
 				$titleObj = $rev->getTitle();
+
 				$wgTitle = $titleObj;
 
-				if ( $this->section !== false ) {
-					$text = $this->getSectionText( $text, 'r' . $rev );
-				}
+				//If for some reason the "oldid" is actually the current revision, it may be cached
+				if ( $titleObj->getLatestRevID() === $oldid ) {
+					$p_result = false;
+					$pcache = ParserCache::singleton();
+					if ( $wgEnableParserCache ) {
+						$p_result = $pcache->get( $titleObj, $popts );
+					}
+					if ( !$p_result ) {
+						$text = $rev->getText( Revision::FOR_THIS_USER );
+						$p_result = $wgParser->parse( $text, $titleObj, $popts );
+
+						if ( $wgEnableParserCache ) {
+							$pcache->save( $p_result, $titleObj, $popts );
+						}
+					}
+				} else {
+					$text = $rev->getText( Revision::FOR_THIS_USER );
+
+					$wgTitle = $titleObj;
 
-				$p_result = $wgParser->parse( $text, $titleObj, $popts );
+					if ( $this->section !== false ) {
+						$text = $this->getSectionText( $text, 'r' . $rev );
+					}
+
+					$p_result = $wgParser->parse( $text, $titleObj, $popts );
+				}
 			} else {
 				if ( !is_null ( $pageid ) ) {
 					$titleObj = Title::newFromID( $pageid );
-- 
2.20.1