resourceloader: Remove isFileModule() overhead from web requests

About 1.5% of load.php wall-time is spent in isFileModule() calls
during the ServiceWiring/getResourceLoader/register call early on.

Reduce the overhead of this cost by moving that logic to the Module
class.

There are two costs that we save this way:

1. The inherent cost of applying the skinStyles.

   This is now limited to only the modules that are constructed in a
   given web request. Thus, apart from the startup response (which
   constructs all modules), for regular load.php requests and all
   index.php page views, the vast majority of modules will never need
   to be constructed, and thus won't pay this cost.

2. The overhead of predicting (and class-loading) for whether a module
   is (or will become) a FileModule object.

   This is what isFileModule() does and is the main reason I wrote
   this patch. It involves class loading, and checks and conditions that
   run 1000+ times at WMF. This is eliminated now because we no longer
   have to calculate this decision. Instead, the logic applies when
   it needs to (due to FileModule implementing it), and doesn't
   when it doesn't!

Change-Id: Ia2db14f930800c96e767b94ef62fb00e9d52725b

1 files changed, 0 insertions, 61 deletions

diff --git a/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php b/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
index a5d88bb8ee79..f3a81ae80249 100644
--- a/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
+++ b/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
@@ -150,67 +150,6 @@ class ResourceLoaderTest extends ResourceLoaderTestCase {
 		);
 	}
 
-	public function provideTestIsFileModule() {
-		$fileModuleObj = $this->createMock( ResourceLoaderFileModule::class );
-		return [
-			'factory ignored' => [ false,
-				[
-					'factory' => static function () {
-						return new ResourceLoaderTestModule();
-					}
-				]
-			],
-			'factory ignored (actual FileModule)' => [ false,
-				[
-					'factory' => static function () use ( $fileModuleObj ) {
-						return $fileModuleObj;
-					}
-				]
-			],
-			'simple empty' => [ true,
-				[]
-			],
-			'simple scripts' => [ true,
-				[ 'scripts' => 'example.js' ]
-			],
-			'simple scripts with targets' => [ true, [
-				'scripts' => [ 'a.js', 'b.js' ],
-				'targets' => [ 'desktop', 'mobile' ],
-			] ],
-			'FileModule' => [ true,
-				[ 'class' => ResourceLoaderFileModule::class, 'scripts' => 'example.js' ]
-			],
-			'TestModule' => [ false,
-				[ 'class' => ResourceLoaderTestModule::class, 'scripts' => 'example.js' ]
-			],
-			'SkinModule (FileModule subclass)' => [ true,
-				[ 'class' => ResourceLoaderSkinModule::class, 'scripts' => 'example.js' ]
-			],
-			'WikiModule' => [ false, [
-				'class' => ResourceLoaderWikiModule::class,
-				'scripts' => [ 'MediaWiki:Example.js' ],
-			] ],
-		];
-	}
-
-	/**
-	 * @dataProvider provideTestIsFileModule
-	 * @covers ResourceLoader::isFileModule
-	 */
-	public function testIsFileModule( $expected, $module ) {
-		$rl = TestingAccessWrapper::newFromObject( new EmptyResourceLoader() );
-		$rl->register( 'test', $module );
-		$this->assertSame( $expected, $rl->isFileModule( 'test' ) );
-	}
-
-	/**
-	 * @covers ResourceLoader::isFileModule
-	 */
-	public function testIsFileModuleUnknown() {
-		$rl = TestingAccessWrapper::newFromObject( new EmptyResourceLoader() );
-		$this->assertSame( false, $rl->isFileModule( 'unknown' ) );
-	}
-
 	/**
 	 * @covers ResourceLoader::isModuleRegistered
 	 */