Mmmm

172 usages in phase3 including comments? :(

tisane2718 wrote:

Before getting rid of $wgTitle, hooks such as AlternateEdit and ParserBeforeStrip should be modified to provide a $title parameter. The manual page on $wgTitle clearly warns about the problems with that global, but sometimes there's no alternative to using it, the way hooks are currently set up.

ParserBeforeStrip is passed a $parser parameter, so you can grab the title with $parser->getTitle() . Similarly, you can use $ep->getArticle()->getTitle() in AlternateEdit.

Looks like from the API's pov, we can just nuke all the "usages" when they've been removed elsewhere etc.

We're just keeping some crappy compatibility by assigning wgTitle to the one we're currently abusing

The situation is even more grave than I thought, adding the following to parserTests.php indicates that even Parser is dependant on it:

class DummyTitle {
public function __call( $name, $args ) {

		throw new MWException( "\$wgTitle::$name() called" );

}
}

$wgTitle = new DummyTitle()

Bryan.TongMinh wrote:

I was looking into this, and it appears that the main culprit is wfMsgExt( $msg, 'parsemag' ), which calls MessageCache::transform and in turn Parser::transformMsg. The way to fix this is to pass a $title object along the entire wfMsg chain.

I used the following code to find out what is calling $wgTitle:

class wgTitleStub extends StubObject {
function __construct( $title ) {

		$this->title = $title;
		parent::__construct( 'wgTitle' );

}
function _newObject() {

		return $this->title;

}
function _unstub( $name = '_unstub', $level = 2 ) {

		parent::_unstub( $name, $level );

		$bt = array();
		foreach ( wfDebugBacktrace() as $line ) {
			if ( isset( $line['class'] ) ) {
				$bt[] = "{$line['class']}::{$line['function']}";
			} else {
				$bt[] = $line['function'];
			}
		}
		wfDebug('Full $wgTitle unstub backtrace: ' . implode( ', ', $bt ) . "\n" );

}
}

Then in Wiki::performRequestForTitle() remove the pass by reference from the function arguments and set $GLOBALS['wgTitle'] = new wgTitleStub( $title );

changed bug title to be less offending.

(In reply to comment #7)

changed bug title to be less offending.

$wgTitle deserves every bit of it, IMO :)

(In reply to comment #8)

(In reply to comment #7)

changed bug title to be less offending.

$wgTitle deserves every bit of it, IMO :)

Adjusted again.

116 usages in phase3...

Quite a few seem to be back compat setting a value, and/or documentation

LanguageConverter probably wants contextsourcing

See bug 53498 comment 10 for a very nasty bug caused by the usage of $wgTitle in AbuseFilter code

Chad is doing a good job in fixing some of them lately ;)

https://gerrit.wikimedia.org/r/#/q/status:open+topic:wgTitle-ugh,n,z

Change 263029 had a related patch set uploaded (by TTO):
DynamicPageListHooks: Set parser context title

https://gerrit.wikimedia.org/r/263029

Change 263030 had a related patch set uploaded (by TTO):
Remove some uses of $wgTitle in core

https://gerrit.wikimedia.org/r/263030

Change 263029 merged by jenkins-bot:
DynamicPageListHooks: Set parser context title

https://gerrit.wikimedia.org/r/263029

The following extensions in git reference $wgTitle at least once in their source code (WMF-deployed extensions marked with *):

* AbuseFilter
  AJAXPoll
  ApprovedRevs
  AuthorProtect
  BlueSpiceExtensions
  BlueSpiceFoundation
  Cargo
  DataTransfer
  DumpHTML
  ErrorHandler
  ExtTab
  GoogleMaps
  JSBreadCrumbs
  Lingo
* LiquidThreads
  MaintenanceShell
  MassEditRegex
  MultiBoilerplate
  OfflineImportLexicon
  PageDisqus
  PageSchemas
* ProofreadPage
  Push
  RandomFeaturedUser
* SecurePoll
  SelectCategory
* SemanticForms
  SemanticMaps
* SemanticMediaWiki
  SemanticPageMaker
* SemanticResultFormats
  ShoutWikiAds
  SimpleSecurity
  SocialProfile
  StarterWiki
* Validator
* VisualEditor
* Wikibase
* WikibaseQueryEngine
* Wikidata
  WikiLexicalData
  Wikilog
  WikiObjectModel
  WYSIWYG

A couple of non-deployed skins use it as well.

Of the deployed extensions that use it, some only assign to it, and never read from it (except for null checks and the like):

• AbuseFilter
• Validator
• VisualEditor
• WikibaseQueryEngine

Other deployed extensions actually use its value, and need to be patched:

• LiquidThreads (used in 2 files)
• ProofreadPage (used in 1 file)
• SecurePoll (used once)
• SemanticForms (used in 6 files)
• SemanticMediaWiki (used in 2 files)
• SemanticResultFormats (used in 2 files)
• Wikibase (used once)
• Wikidata (used in 2 files)

As usual, SMW is a big offender here.

Change 263030 abandoned by Krinkle:
Remove some uses of $wgTitle in core

Reason:
All uses in core seem to've been updated in master. Thanks anyway!

https://gerrit.wikimedia.org/r/263030

Change 938919 had a related patch set uploaded (by Mainframe98; author: Mainframe98):

[mediawiki/core@master] parser: Plug gaps in nullability of Parser::mTitle

https://gerrit.wikimedia.org/r/938919

Change 938877 had a related patch set uploaded (by Mainframe98; author: Mainframe98):

[mediawiki/core@master] API: Do not initialize $wgTitle to a bad title anymore

https://gerrit.wikimedia.org/r/938877

Change 938857 had a related patch set uploaded (by Mainframe98; author: Mainframe98):

[mediawiki/core@master] Remove remaining usages of $wgTitle and deprecate it

https://gerrit.wikimedia.org/r/938857

Just to confirm: the wgTitle JavaScript config value is completely unrelated, and there is no plan to deprecate it ever, right?

In T25307#9331311, @Od1n wrote:

Just to confirm: the wgTitle JavaScript config value is completely unrelated, and there is no plan to deprecate it ever, right?

Yes. That's just a string of the current page title and unrelated to this work. Maybe it should be renamed, but that's totally outside of this scope.

Change #1043019 had a related patch set uploaded (by Bartosz Dziewoński; author: Bartosz Dziewoński):

[mediawiki/core@master] Rest: Do not set $wgTitle

https://gerrit.wikimedia.org/r/1043019

Change #1043019 merged by jenkins-bot:

[mediawiki/core@master] Rest: Do not set $wgTitle

https://gerrit.wikimedia.org/r/1043019

Change #938919 abandoned by Mainframe98:

[mediawiki/core@master] parser: Plug gaps in nullability of public methods

https://gerrit.wikimedia.org/r/938919

Change #938877 abandoned by Mainframe98:

[mediawiki/core@master] API: Do not initialize $wgTitle to a bad title anymore

https://gerrit.wikimedia.org/r/938877

Change #938857 abandoned by Mainframe98:

[mediawiki/core@master] Remove remaining usages of $wgTitle and deprecate it

https://gerrit.wikimedia.org/r/938857

No subtasks remain open. You can almost feel the radiant warmth of the fiery pit as it beckons us closer and closer! But alas, we are not ready yet.

There are various places across MW core and extensions that only set $wgTitle, not read from it. These are harmless enough.

More problematic are the remaining cases where code reads from $wgTitle:

[list moved to task description]

In T25307#11573259, @TTO wrote:

• LiquidThreads (task open for its undeployment: T350164 but I remain skeptical that that will ever be done)

Effectively this is also write-only: it reads out the old value, writes a new one, and later writes back the old value. The old value ($oldTitle) is not used for anything but for being written back to $wgTitle, so the code won’t break if $wgTitle becomes null by default.