Title::getContentModel(): load from DB if necessary

Also don't cast $model to int in LinkCache::addGoodLinkObj(); content
model IDs are non-numeric strings, not integers, so that field was
always populated with the value 0. Because 0 is a falsy value, this
caused subsequent calls to Title::getContentModel() to return the
default model rather than the correct one.

Also (hopefully) fixed every single query that could cause a
LinkCache entry to be added without the content model.

Bug: 69789
Change-Id: I94f06baf406afa538cd2b10139598442f9fc6759

RELEASE-NOTES-1.24

@@ -196,6 +196,8 @@ production.
 * (bug 67870) wfShellExec() cuts off stdout at multiples of 8192 bytes.
 * $wgRunJobsAsync now works with private wikis (e.g. read requires login).
 * (bugs 57238, 65206) Blank pages can now be directly created.
+* (bug 69789) Title::getContentModel() now loads from the database when
+  necessary instead of incorrectly returning the default content model.
 
 === Web API changes in 1.24 ===
 * action=parse API now supports prop=modules, which provides the list of

includes/OutputPage.php

@@ -1240,7 +1240,7 @@ class OutputPage extends ContextSource {
 	 * @param array $categories Mapping category name => sort key
 	 */
 	public function addCategoryLinks( array $categories ) {
-		global $wgContLang;
+		global $wgContLang, $wgContentHandlerUseDB;
 
 		if ( !is_array( $categories ) || count( $categories ) == 0 ) {
 			return;
@@ -1253,9 +1253,15 @@ class OutputPage extends ContextSource {
 
 		# Fetch existence plus the hiddencat property
 		$dbr = wfGetDB( DB_SLAVE );
+		$fields = array( 'page_id', 'page_namespace', 'page_title', 'page_len',
+			'page_is_redirect', 'page_latest', 'pp_value' );
+
+		if ( $wgContentHandlerUseDB ) {
+			$fields[] = 'page_content_model';
+		}
+
 		$res = $dbr->select( array( 'page', 'page_props' ),
-			array( 'page_id', 'page_namespace', 'page_title', 'page_len',
-				'page_is_redirect', 'page_latest', 'pp_value' ),
+			$fields,
 			$lb->constructSet( 'page', $dbr ),
 			__METHOD__,
 			array(),

includes/Title.php

@@ -944,10 +944,12 @@ class Title {
 	 * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 	 *
 	 * @throws MWException
+	 * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 	 * @return string Content model id
 	 */
-	public function getContentModel() {
-		if ( !$this->mContentModel ) {
+	public function getContentModel( $flags = 0 ) {
+		# Calling getArticleID() loads the field from cache as needed
+		if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 			$linkCache = LinkCache::singleton();
 			$this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 		}

includes/cache/LinkBatch.php

@@ -180,6 +180,8 @@ class LinkBatch {
 	 * @return bool|ResultWrapper
 	 */
 	public function doQuery() {
+		global $wgContentHandlerUseDB;
+
 		if ( $this->isEmpty() ) {
 			return false;
 		}
@@ -190,6 +192,11 @@ class LinkBatch {
 		$table = 'page';
 		$fields = array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 			'page_is_redirect', 'page_latest' );
+
+		if ( $wgContentHandlerUseDB ) {
+			$fields[] = 'page_content_model';
+		}
+
 		$conds = $this->constructSet( 'page', $dbr );
 
 		// Do query

includes/cache/LinkCache.php

@@ -129,10 +129,10 @@ class LinkCache {
 	 * @param int $len Text's length
 	 * @param int $redir Whether the page is a redirect
 	 * @param int $revision Latest revision's ID
-	 * @param int $model Latest revision's content model ID
+	 * @param string|null $model Latest revision's content model ID
 	 */
 	public function addGoodLinkObj( $id, $title, $len = -1, $redir = null,
-		$revision = 0, $model = 0
+		$revision = 0, $model = null
 	) {
 		$dbkey = $title->getPrefixedDBkey();
 		$this->mGoodLinks[$dbkey] = (int)$id;
@@ -140,7 +140,7 @@ class LinkCache {
 			'length' => (int)$len,
 			'redirect' => (int)$redir,
 			'revision' => (int)$revision,
-			'model' => (int)$model
+			'model' => $model ? (string)$model : null,
 		);
 	}
 

includes/parser/LinkHolderArray.php

@@ -290,7 +290,7 @@ class LinkHolderArray {
 		}
 
 		wfProfileIn( __METHOD__ );
-		global $wgContLang;
+		global $wgContLang, $wgContentHandlerUseDB;
 
 		$colours = array();
 		$linkCache = LinkCache::singleton();
@@ -348,10 +348,16 @@ class LinkHolderArray {
 				);
 			}
 
+			$fields = array( 'page_id', 'page_namespace', 'page_title',
+				'page_is_redirect', 'page_len', 'page_latest' );
+
+			if ( $wgContentHandlerUseDB ) {
+				$fields[] = 'page_content_model';
+			}
+
 			$res = $dbr->select(
 				'page',
-				array( 'page_id', 'page_namespace', 'page_title',
-					'page_is_redirect', 'page_len', 'page_latest' ),
+				$fields,
 				$dbr->makeList( $where, LIST_OR ),
 				__METHOD__
 			);
@@ -465,7 +471,7 @@ class LinkHolderArray {
 	 * @param array $colours
 	 */
 	protected function doVariants( &$colours ) {
-		global $wgContLang;
+		global $wgContLang, $wgContentHandlerUseDB;
 		$linkBatch = new LinkBatch();
 		$variantMap = array(); // maps $pdbkey_Variant => $keys (of link holders)
 		$output = $this->parent->getOutput();
@@ -554,9 +560,15 @@ class LinkHolderArray {
 		if ( !$linkBatch->isEmpty() ) {
 			// construct query
 			$dbr = wfGetDB( DB_SLAVE );
+			$fields = array( 'page_id', 'page_namespace', 'page_title',
+				'page_is_redirect', 'page_len', 'page_latest' );
+
+			if ( $wgContentHandlerUseDB ) {
+				$fields[] = 'page_content_model';
+			}
+
 			$varRes = $dbr->select( 'page',
-				array( 'page_id', 'page_namespace', 'page_title',
-					'page_is_redirect', 'page_len', 'page_latest' ),
+				$fields,
 				$linkBatch->constructSet( 'page', $dbr ),
 				__METHOD__
 			);