Merge "Allow callback functions for creating jobs"

RELEASE-NOTES-1.30

@@ -12,6 +12,11 @@ production.
   case.
 * $wgShellLocale now affects LC_ALL rather than only LC_CTYPE. See
   documentation of $wgShellLocale for details.
+* $wgJobClasses may now specify callback functions
+  as an alternative to plain class names.
+  This is intended for extensions that want control
+  over the instantiation of their jobs,
+  to allow for proper dependency injection.
 
 === New features in 1.30 ===
 * (T37247) Output from Parser::parse() will now be wrapped in a div with

docs/extension.schema.v1.json

@@ -576,7 +576,7 @@
 		},
 		"JobClasses": {
 			"type": "object",
-			"description": "Job types this extension implements (mapping of job type to class name)"
+			"description": "Job types this extension implements (mapping of job type to class name or factory function)"
 		},
 		"LogTypes": {
 			"type": "array",

docs/extension.schema.v2.json

@@ -586,7 +586,7 @@
 		},
 		"JobClasses": {
 			"type": "object",
-			"description": "Job types this extension implements (mapping of job type to class name)"
+			"description": "Job types this extension implements (mapping of job type to class name or factory function)"
 		},
 		"LogTypes": {
 			"type": "array",

includes/DefaultSettings.php

@@ -7323,8 +7323,10 @@ $wgServiceWiringFiles = [
 ];
 
 /**
- * Maps jobs to their handling classes; extensions
- * can add to this to provide custom jobs
+ * Maps jobs to their handlers; extensions
+ * can add to this to provide custom jobs.
+ * A job handler should either be a class name to be instantiated,
+ * or (since 1.30) a callback to use for creating the job object.
  */
 $wgJobClasses = [
 	'refreshLinks' => 'RefreshLinksJob',

includes/jobqueue/Job.php

@@ -69,12 +69,22 @@ abstract class Job implements IJobSpecification {
 		global $wgJobClasses;
 
 		if ( isset( $wgJobClasses[$command] ) ) {
-			$class = $wgJobClasses[$command];
+			$handler = $wgJobClasses[$command];
 
-			$job = new $class( $title, $params );
-			$job->command = $command;
+			if ( is_callable( $handler ) ) {
+				$job = call_user_func( $handler, $title, $params );
+			} elseif ( class_exists( $handler ) ) {
+				$job = new $handler( $title, $params );
+			} else {
+				$job = null;
+			}
 
-			return $job;
+			if ( $job instanceof Job ) {
+				$job->command = $command;
+				return $job;
+			} else {
+				throw new InvalidArgumentException( "Cannot instantiate job '$command': bad spec!" );
+			}
 		}
 
 		throw new InvalidArgumentException( "Invalid job command '{$command}'" );

tests/phpunit/includes/jobqueue/JobTest.php

@@ -91,4 +91,41 @@ class JobTest extends MediaWikiTestCase {
 		return $mock;
 	}
 
+	/**
+	 * @dataProvider provideTestJobFactory
+	 *
+	 * @param mixed $handler
+	 *
+	 * @covers Job::factory
+	 */
+	public function testJobFactory( $handler ) {
+		$this->mergeMWGlobalArrayValue( 'wgJobClasses', [ 'testdummy' => $handler ] );
+
+		$job = Job::factory( 'testdummy', Title::newMainPage(), [] );
+		$this->assertInstanceOf( NullJob::class, $job );
+
+		$job2 = Job::factory( 'testdummy', Title::newMainPage(), [] );
+		$this->assertInstanceOf( NullJob::class, $job2 );
+		$this->assertNotSame( $job, $job2, 'should not reuse instance' );
+	}
+
+	public function provideTestJobFactory() {
+		return [
+			'class name' => [ 'NullJob' ],
+			'closure' => [ function( Title $title, array $params ) {
+				return new NullJob( $title, $params );
+			} ],
+			'function' => [ [ $this, 'newNullJob' ] ],
+			'static function' => [ self::class . '::staticNullJob' ]
+		];
+	}
+
+	public function newNullJob( Title $title, array $params ) {
+		return new NullJob( $title, $params );
+	}
+
+	public static function staticNullJob( Title $title, array $params ) {
+		return new NullJob( $title, $params );
+	}
+
 }