Prefer console.error over console.log for exception logging
[lhc/web/wiklou.git] / resources / mediawiki / mediawiki.js
index eb281f8..793cf22 100644 (file)
@@ -138,7 +138,7 @@ var mw = ( function ( $, undefined ) {
                /**
                 * Simple message parser, does $N replacement and nothing else.
                 * This may be overridden to provide a more complex message parser.
-                * 
+                *
                 * This function will not be called for nonexistent messages.
                 */
                parser: function() {
@@ -148,7 +148,7 @@ var mw = ( function ( $, undefined ) {
                                return parameters[index] !== undefined ? parameters[index] : '$' + match;
                        } );
                },
-               
+
                /**
                 * Appends (does not replace) parameters for replacement to the .parameters property.
                 *
@@ -192,7 +192,7 @@ var mw = ( function ( $, undefined ) {
                                text = this.parser();
                                text = mw.html.escape( text );
                        }
-                       
+
                        if ( this.format === 'parse' ) {
                                text = this.parser();
                        }
@@ -248,7 +248,7 @@ var mw = ( function ( $, undefined ) {
                 * emulates console.log in console-less environments.
                 */
                log: function() { },
-       
+
                /**
                 * @var constructor Make the Map constructor publicly available.
                 */
@@ -258,7 +258,7 @@ var mw = ( function ( $, undefined ) {
                 * @var constructor Make the Message constructor publicly available.
                 */
                Message: Message,
-       
+
                /**
                 * List of configuration values
                 *
@@ -267,25 +267,25 @@ var mw = ( function ( $, undefined ) {
                 * in the global window object.
                 */
                config: null,
-       
+
                /**
                 * @var object
                 *
                 * Empty object that plugins can be installed in.
                 */
                libs: {},
-       
+
                /* Extension points */
-       
+
                legacy: {},
-       
+
                /**
                 * Localization system
                 */
                messages: new Map(),
-       
+
                /* Public Methods */
-       
+
                /**
                 * Gets a message object, similar to wfMessage()
                 *
@@ -305,7 +305,7 @@ var mw = ( function ( $, undefined ) {
                        }
                        return new Message( mw.messages, key, parameters );
                },
-       
+
                /**
                 * Gets a message string, similar to wfMsg()
                 *
@@ -317,14 +317,14 @@ var mw = ( function ( $, undefined ) {
                msg: function ( /* key, parameter_1, parameter_2, .. */ ) {
                        return mw.message.apply( mw.message, arguments ).toString();
                },
-       
+
                /**
                 * Client-side module loader which integrates with the MediaWiki ResourceLoader
                 */
                loader: ( function () {
-       
+
                        /* Private Members */
-       
+
                        /**
                         * Mapping of registered modules
                         *
@@ -372,15 +372,15 @@ var mw = ( function ( $, undefined ) {
                                ready = false,
                                // Selector cache for the marker element. Use getMarker() to get/use the marker!
                                $marker = null;
-       
+
                        /* Cache document ready status */
-       
+
                        $(document).ready( function () {
                                ready = true;
                        } );
-       
+
                        /* Private methods */
-       
+
                        function getMarker() {
                                // Cached ?
                                if ( $marker ) {
@@ -464,7 +464,7 @@ var mw = ( function ( $, undefined ) {
                                }
                                return true;
                        }
-       
+
                        /**
                         * Generates an ISO8601 "basic" string from a UNIX timestamp
                         */
@@ -479,13 +479,23 @@ var mw = ( function ( $, undefined ) {
                                        pad( d.getUTCHours(), d.getUTCMinutes(), d.getUTCSeconds() ), 'Z'
                                ].join( '' );
                        }
-       
+
                        /**
-                        * Recursively resolves dependencies and detects circular references
+                        * Resolves dependencies and detects circular references.
+                        *
+                        * @param module String Name of the top-level module whose dependencies shall be
+                        *   resolved and sorted.
+                        * @param resolved Array Returns a topological sort of the given module and its
+                        *   dependencies, such that later modules depend on earlier modules. The array
+                        *   contains the module names. If the array contains already some module names,
+                        *   this function appends its result to the pre-existing array.
+                        * @param unresolved Object [optional] Hash used to track the current dependency
+                        *   chain; used to report loops in the dependency graph.
+                        * @throws Error if any unregistered module or a dependency loop is encountered
                         */
-                       function recurse( module, resolved, unresolved ) {
+                       function sortDependencies( module, resolved, unresolved ) {
                                var n, deps, len;
-       
+
                                if ( registry[module] === undefined ) {
                                        throw new Error( 'Unknown dependency: ' + module );
                                }
@@ -497,12 +507,20 @@ var mw = ( function ( $, undefined ) {
                                                registry[module].dependencies = [registry[module].dependencies];
                                        }
                                }
+                               if ( $.inArray( module, resolved ) !== -1 ) {
+                                       // Module already resolved; nothing to do.
+                                       return;
+                               }
+                               // unresolved is optional, supply it if not passed in
+                               if ( !unresolved ) {
+                                       unresolved = {};
+                               }
                                // Tracks down dependencies
                                deps = registry[module].dependencies;
                                len = deps.length;
                                for ( n = 0; n < len; n += 1 ) {
                                        if ( $.inArray( deps[n], resolved ) === -1 ) {
-                                               if ( $.inArray( deps[n], unresolved ) !== -1 ) {
+                                               if ( unresolved[deps[n]] ) {
                                                        throw new Error(
                                                                'Circular reference detected: ' + module +
                                                                ' -> ' + deps[n]
@@ -510,46 +528,43 @@ var mw = ( function ( $, undefined ) {
                                                }
 
                                                // Add to unresolved
-                                               unresolved[unresolved.length] = module;
-                                               recurse( deps[n], resolved, unresolved );
-                                               // module is at the end of unresolved
-                                               unresolved.pop();
+                                               unresolved[module] = true;
+                                               sortDependencies( deps[n], resolved, unresolved );
+                                               delete unresolved[module];
                                        }
                                }
                                resolved[resolved.length] = module;
                        }
-       
+
                        /**
-                        * Gets a list of module names that a module depends on in their proper dependency order
+                        * Gets a list of module names that a module depends on in their proper dependency
+                        * order.
                         *
                         * @param module string module name or array of string module names
                         * @return list of dependencies, including 'module'.
                         * @throws Error if circular reference is detected
                         */
                        function resolve( module ) {
-                               var modules, m, deps, n, resolved;
-       
+                               var m, resolved;
+
                                // Allow calling with an array of module names
                                if ( $.isArray( module ) ) {
-                                       modules = [];
+                                       resolved = [];
                                        for ( m = 0; m < module.length; m += 1 ) {
-                                               deps = resolve( module[m] );
-                                               for ( n = 0; n < deps.length; n += 1 ) {
-                                                       modules[modules.length] = deps[n];
-                                               }
+                                               sortDependencies( module[m], resolved );
                                        }
-                                       return modules;
+                                       return resolved;
                                }
 
                                if ( typeof module === 'string' ) {
                                        resolved = [];
-                                       recurse( module, resolved, [] );
+                                       sortDependencies( module, resolved );
                                        return resolved;
                                }
 
                                throw new Error( 'Invalid module argument: ' + module );
                        }
-       
+
                        /**
                         * Narrows a list of module names down to those matching a specific
                         * state (see comment on top of this scope for a list of valid states).
@@ -563,7 +578,7 @@ var mw = ( function ( $, undefined ) {
                         */
                        function filter( states, modules ) {
                                var list, module, s, m;
-       
+
                                // Allow states to be given as a string
                                if ( typeof states === 'string' ) {
                                        states = [states];
@@ -596,59 +611,113 @@ var mw = ( function ( $, undefined ) {
                                }
                                return list;
                        }
-       
+
+                       /**
+                        * Determine whether all dependencies are in state 'ready', which means we may
+                        * execute the module or job now.
+                        *
+                        * @param dependencies Array dependencies (module names) to be checked.
+                        *
+                        * @return Boolean true if all dependencies are in state 'ready', false otherwise
+                        */
+                       function allReady( dependencies ) {
+                               return filter( 'ready', dependencies ).length === dependencies.length;
+                       }
+
+                       /**
+                        * Log a message to window.console, if possible. Useful to force logging of some
+                        * errors that are otherwise hard to detect (I.e., this logs also in production mode).
+                        * Gets console references in each invocation, so that delayed debugging tools work
+                        * fine. No need for optimization here, which would only result in losing logs.
+                        *
+                        * @param msg String text for the log entry.
+                        * @param e Error [optional] to also log.
+                        */
+                       function log( msg, e ) {
+                               var console = window.console;
+                               if ( console && console.log ) {
+                                       console.log( msg );
+                                       // console.error triggers the proper handling of exception objects in
+                                       // consoles that support it. Fallback to passing as plain object to log().
+                                       if ( e ) {
+                                               (console.error || console.log).call( console, e );
+                                       }
+                               }
+                       }
+
                        /**
-                        * Automatically executes jobs and modules which are pending with satistifed dependencies.
+                        * A module has entered state 'ready', 'error', or 'missing'. Automatically update pending jobs
+                        * and modules that depend upon this module. if the given module failed, propagate the 'error'
+                        * state up the dependency tree; otherwise, execute all jobs/modules that now have all their
+                        * dependencies satisfied. On jobs depending on a failed module, run the error callback, if any.
                         *
-                        * This is used when dependencies are satisfied, such as when a module is executed.
+                        * @param module String name of module that entered one of the states 'ready', 'error', or 'missing'.
                         */
                        function handlePending( module ) {
-                               var j, r;
-       
-                               try {
-                                       // Run jobs whose dependencies have just been met
-                                       for ( j = 0; j < jobs.length; j += 1 ) {
-                                               if ( compare(
-                                                       filter( 'ready', jobs[j].dependencies ),
-                                                       jobs[j].dependencies ) )
-                                               {
-                                                       var callback = jobs[j].ready;
-                                                       jobs.splice( j, 1 );
-                                                       j -= 1;
-                                                       if ( $.isFunction( callback ) ) {
-                                                               callback();
+                               var j, job, hasErrors, m, stateChange;
+
+                               // Modules.
+                               if ( $.inArray( registry[module].state, ['error', 'missing'] ) !== -1 ) {
+                                       // If the current module failed, mark all dependent modules also as failed.
+                                       // Iterate until steady-state to propagate the error state upwards in the
+                                       // dependency tree.
+                                       do {
+                                               stateChange = false;
+                                               for ( m in registry ) {
+                                                       if ( $.inArray( registry[m].state, ['error', 'missing'] ) === -1 ) {
+                                                               if ( filter( ['error', 'missing'], registry[m].dependencies ).length > 0 ) {
+                                                                       registry[m].state = 'error';
+                                                                       stateChange = true;
+                                                               }
                                                        }
                                                }
-                                       }
-                                       // Execute modules whose dependencies have just been met
-                                       for ( r in registry ) {
-                                               if ( registry[r].state === 'loaded' ) {
-                                                       if ( compare(
-                                                               filter( ['ready'], registry[r].dependencies ),
-                                                               registry[r].dependencies ) )
-                                                       {
-                                                               execute( r );
+                                       } while ( stateChange );
+                               }
+
+                               // Execute all jobs whose dependencies are either all satisfied or contain at least one failed module.
+                               for ( j = 0; j < jobs.length; j += 1 ) {
+                                       hasErrors = filter( ['error', 'missing'], jobs[j].dependencies ).length > 0;
+                                       if ( hasErrors || allReady( jobs[j].dependencies ) ) {
+                                               // All dependencies satisfied, or some have errors
+                                               job = jobs[j];
+                                               jobs.splice( j, 1 );
+                                               j -= 1;
+                                               try {
+                                                       if ( hasErrors ) {
+                                                               throw new Error ("Module " + module + " failed.");
+                                                       } else {
+                                                               if ( $.isFunction( job.ready ) ) {
+                                                                       job.ready();
+                                                               }
+                                                       }
+                                               } catch ( e ) {
+                                                       if ( $.isFunction( job.error ) ) {
+                                                               try {
+                                                                       job.error( e, [module] );
+                                                               } catch ( ex ) {
+                                                                       // A user-defined operation raised an exception. Swallow to protect
+                                                                       // our state machine!
+                                                                       log( 'mw.loader::handlePending> Exception thrown by job.error()', ex );
+                                                               }
                                                        }
                                                }
                                        }
-                               } catch ( e ) {
-                                       // Run error callbacks of jobs affected by this condition
-                                       for ( j = 0; j < jobs.length; j += 1 ) {
-                                               if ( $.inArray( module, jobs[j].dependencies ) !== -1 ) {
-                                                       if ( $.isFunction( jobs[j].error ) ) {
-                                                               jobs[j].error( e, module );
-                                                       }
-                                                       jobs.splice( j, 1 );
-                                                       j -= 1;
+                               }
+
+                               if ( registry[module].state === 'ready' ) {
+                                       // The current module became 'ready'. Recursively execute all dependent modules that are loaded
+                                       // and now have all dependencies satisfied.
+                                       for ( m in registry ) {
+                                               if ( registry[m].state === 'loaded' && allReady( registry[m].dependencies ) ) {
+                                                       execute( m );
                                                }
                                        }
-                                       throw e;
                                }
                        }
-       
+
                        /**
                         * Adds a script tag to the DOM, either using document.write or low-level DOM manipulation,
-                        * depending on whether document-ready has occured yet and whether we are in async mode.
+                        * depending on whether document-ready has occurred yet and whether we are in async mode.
                         *
                         * @param src String: URL to script, will be used as the src attribute in the script tag
                         * @param callback Function: Optional callback which will be run when the script is done
@@ -665,7 +734,7 @@ var mw = ( function ( $, undefined ) {
                                        if ( $.isFunction( callback ) ) {
                                                // Attach handlers for all browsers (based on jQuery.ajax)
                                                script.onload = script.onreadystatechange = function() {
-       
+
                                                        if (
                                                                !done
                                                                && (
@@ -673,11 +742,11 @@ var mw = ( function ( $, undefined ) {
                                                                        || /loaded|complete/.test( script.readyState )
                                                                )
                                                        ) {
-       
+
                                                                done = true;
-       
+
                                                                callback();
-       
+
                                                                // Handle memory leak in IE. This seems to fail in
                                                                // IE7 sometimes (Permission Denied error when
                                                                // accessing script.parentNode) so wrap it in
@@ -687,14 +756,14 @@ var mw = ( function ( $, undefined ) {
                                                                        if ( script.parentNode ) {
                                                                                script.parentNode.removeChild( script );
                                                                        }
-               
+
                                                                        // Dereference the script
                                                                        script = undefined;
                                                                } catch ( e ) { }
                                                        }
                                                };
                                        }
-                                       
+
                                        if ( window.opera ) {
                                                // Appending to the <head> blocks rendering completely in Opera,
                                                // so append to the <body> after document ready. This means the
@@ -719,15 +788,15 @@ var mw = ( function ( $, undefined ) {
                                        }
                                }
                        }
-       
+
                        /**
                         * Executes a loaded module, making it ready to use
                         *
                         * @param module string module name to execute
                         */
-                       function execute( module, callback ) {
+                       function execute( module ) {
                                var style, media, i, script, markModuleReady, nestedAddScript;
-       
+
                                if ( registry[module] === undefined ) {
                                        throw new Error( 'Module has not been registered yet: ' + module );
                                } else if ( registry[module].state === 'registered' ) {
@@ -737,7 +806,7 @@ var mw = ( function ( $, undefined ) {
                                } else if ( registry[module].state === 'ready' ) {
                                        throw new Error( 'Module has already been loaded: ' + module );
                                }
-       
+
                                // Add styles
                                if ( $.isPlainObject( registry[module].style ) ) {
                                        // 'media' type ignored, see documentation of mw.loader.implement
@@ -766,9 +835,6 @@ var mw = ( function ( $, undefined ) {
                                        markModuleReady = function() {
                                                registry[module].state = 'ready';
                                                handlePending( module );
-                                               if ( $.isFunction( callback ) ) {
-                                                       callback();
-                                               }
                                        };
                                        nestedAddScript = function ( arr, callback, async, i ) {
                                                // Recursively call addScript() in its own callback
@@ -778,12 +844,12 @@ var mw = ( function ( $, undefined ) {
                                                        callback();
                                                        return;
                                                }
-       
+
                                                addScript( arr[i], function() {
                                                        nestedAddScript( arr, callback, async, i + 1 );
                                                }, async );
                                        };
-       
+
                                        if ( $.isArray( script ) ) {
                                                registry[module].state = 'loading';
                                                nestedAddScript( script, markModuleReady, registry[module].async, 0 );
@@ -794,14 +860,12 @@ var mw = ( function ( $, undefined ) {
                                } catch ( e ) {
                                        // This needs to NOT use mw.log because these errors are common in production mode
                                        // and not in debug mode, such as when a symbol that should be global isn't exported
-                                       if ( window.console && typeof window.console.log === 'function' ) {
-                                               console.log( 'mw.loader::execute> Exception thrown by ' + module + ': ' + e.message );
-                                               console.log( e );
-                                       }
+                                       log('mw.loader::execute> Exception thrown by ' + module + ': ' + e.message, e);
                                        registry[module].state = 'error';
+                                       handlePending( module );
                                }
                        }
-       
+
                        /**
                         * Adds a dependencies to the queue with optional callbacks to be run
                         * when the dependencies are ready or fail
@@ -814,7 +878,7 @@ var mw = ( function ( $, undefined ) {
                         */
                        function request( dependencies, ready, error, async ) {
                                var regItemDeps, regItemDepLen, n;
-       
+
                                // Allow calling by single module name
                                if ( typeof dependencies === 'string' ) {
                                        dependencies = [dependencies];
@@ -856,7 +920,7 @@ var mw = ( function ( $, undefined ) {
                                // Work the queue
                                mw.loader.work();
                        }
-       
+
                        function sortQuery(o) {
                                var sorted = {}, key, a = [];
                                for ( key in o ) {
@@ -870,7 +934,7 @@ var mw = ( function ( $, undefined ) {
                                }
                                return sorted;
                        }
-       
+
                        /**
                         * Converts a module map of the form { foo: [ 'bar', 'baz' ], bar: [ 'baz, 'quux' ] }
                         * to a query string of the form foo.bar,baz|bar.baz,quux
@@ -883,7 +947,7 @@ var mw = ( function ( $, undefined ) {
                                }
                                return arr.join( '|' );
                        }
-       
+
                        /**
                         * Asynchronously append a script tag to the end of the body
                         * that invokes load.php
@@ -902,7 +966,7 @@ var mw = ( function ( $, undefined ) {
                                // Append &* to avoid triggering the IE6 extension check
                                addScript( sourceLoadScript + '?' + $.param( request ) + '&*', null, async );
                        }
-       
+
                        /* Public Methods */
                        return {
                                addStyleTag: addStyleTag,
@@ -915,7 +979,7 @@ var mw = ( function ( $, undefined ) {
                                                source, group, g, i, modules, maxVersion, sourceLoadScript,
                                                currReqBase, currReqBaseLength, moduleMap, l,
                                                lastDotIndex, prefix, suffix, bytesAdded, async;
-               
+
                                        // Build a list of request parameters common to all requests.
                                        reqBase = {
                                                skin: mw.config.get( 'skin' ),
@@ -925,7 +989,7 @@ var mw = ( function ( $, undefined ) {
                                        // Split module batch by source and by group.
                                        splits = {};
                                        maxQueryLength = mw.config.get( 'wgResourceLoaderMaxQueryLength', -1 );
-               
+
                                        // Appends a list of modules from the queue to the batch
                                        for ( q = 0; q < queue.length; q += 1 ) {
                                                // Only request modules which are registered
@@ -942,14 +1006,14 @@ var mw = ( function ( $, undefined ) {
                                        if ( !batch.length ) {
                                                return;
                                        }
-               
+
                                        // The queue has been processed into the batch, clear up the queue.
                                        queue = [];
-               
+
                                        // Always order modules alphabetically to help reduce cache
                                        // misses for otherwise identical content.
                                        batch.sort();
-               
+
                                        // Split batch by source and by group.
                                        for ( b = 0; b < batch.length; b += 1 ) {
                                                bSource = registry[batch[b]].source;
@@ -963,24 +1027,24 @@ var mw = ( function ( $, undefined ) {
                                                bSourceGroup = splits[bSource][bGroup];
                                                bSourceGroup[bSourceGroup.length] = batch[b];
                                        }
-               
+
                                        // Clear the batch - this MUST happen before we append any
                                        // script elements to the body or it's possible that a script
                                        // will be locally cached, instantly load, and work the batch
                                        // again, all before we've cleared it causing each request to
                                        // include modules which are already loaded.
                                        batch = [];
-               
+
                                        for ( source in splits ) {
-               
+
                                                sourceLoadScript = sources[source].loadScript;
-               
+
                                                for ( group in splits[source] ) {
-               
+
                                                        // Cache access to currently selected list of
                                                        // modules for this group from this source.
                                                        modules = splits[source][group];
-               
+
                                                        // Calculate the highest timestamp
                                                        maxVersion = 0;
                                                        for ( g = 0; g < modules.length; g += 1 ) {
@@ -988,16 +1052,20 @@ var mw = ( function ( $, undefined ) {
                                                                        maxVersion = registry[modules[g]].version;
                                                                }
                                                        }
-               
+
                                                        currReqBase = $.extend( { 'version': formatVersionNumber( maxVersion ) }, reqBase );
+                                                       // For user modules append a user name to the request.
+                                                       if ( group === "user" && mw.config.get( 'wgUserName' ) !== null ) {
+                                                               currReqBase.user = mw.config.get( 'wgUserName' );
+                                                       }
                                                        currReqBaseLength = $.param( currReqBase ).length;
                                                        async = true;
                                                        // We may need to split up the request to honor the query string length limit,
                                                        // so build it piece by piece.
                                                        l = currReqBaseLength + 9; // '&modules='.length == 9
-               
+
                                                        moduleMap = {}; // { prefix: [ suffixes ] }
-               
+
                                                        for ( i = 0; i < modules.length; i += 1 ) {
                                                                // Determine how many bytes this module would add to the query string
                                                                lastDotIndex = modules[i].lastIndexOf( '.' );
@@ -1007,7 +1075,7 @@ var mw = ( function ( $, undefined ) {
                                                                bytesAdded = moduleMap[prefix] !== undefined
                                                                        ? suffix.length + 3 // '%2C'.length == 3
                                                                        : modules[i].length + 3; // '%7C'.length == 3
-               
+
                                                                // If the request would become too long, create a new one,
                                                                // but don't create empty requests
                                                                if ( maxQueryLength > 0 && !$.isEmptyObject( moduleMap ) && l + bytesAdded > maxQueryLength ) {
@@ -1037,7 +1105,7 @@ var mw = ( function ( $, undefined ) {
                                                }
                                        }
                                },
-               
+
                                /**
                                 * Register a source.
                                 *
@@ -1055,16 +1123,16 @@ var mw = ( function ( $, undefined ) {
                                                }
                                                return true;
                                        }
-               
+
                                        if ( sources[id] !== undefined ) {
                                                throw new Error( 'source already registered: ' + id );
                                        }
-               
+
                                        sources[id] = props;
-               
+
                                        return true;
                                },
-               
+
                                /**
                                 * Registers a module, letting the system know about it and its
                                 * properties. Startup modules contain calls to this function.
@@ -1115,7 +1183,7 @@ var mw = ( function ( $, undefined ) {
                                                registry[module].dependencies = dependencies;
                                        }
                                },
-               
+
                                /**
                                 * Implements a module, giving the system a course of action to take
                                 * upon loading. Results of a request for one or more modules contain
@@ -1157,21 +1225,19 @@ var mw = ( function ( $, undefined ) {
                                        if ( registry[module] !== undefined && registry[module].script !== undefined ) {
                                                throw new Error( 'module already implemented: ' + module );
                                        }
-                                       // Mark module as loaded
-                                       registry[module].state = 'loaded';
                                        // Attach components
                                        registry[module].script = script;
                                        registry[module].style = style;
                                        registry[module].messages = msgs;
-                                       // Execute or queue callback
-                                       if ( compare(
-                                               filter( ['ready'], registry[module].dependencies ),
-                                               registry[module].dependencies ) )
-                                       {
-                                               execute( module );
+                                       // The module may already have been marked as erroneous
+                                       if ( $.inArray( registry[module].state, ['error', 'missing'] ) === -1 ) {
+                                               registry[module].state = 'loaded';
+                                               if ( allReady( registry[module].dependencies ) ) {
+                                                       execute( module );
+                                               }
                                        }
                                },
-               
+
                                /**
                                 * Executes a function as soon as one or more required modules are ready
                                 *
@@ -1192,25 +1258,23 @@ var mw = ( function ( $, undefined ) {
                                        }
                                        // Resolve entire dependency map
                                        dependencies = resolve( dependencies );
-                                       // If all dependencies are met, execute ready immediately
-                                       if ( compare( filter( ['ready'], dependencies ), dependencies ) ) {
+                                       if ( allReady( dependencies ) ) {
+                                               // Run ready immediately
                                                if ( $.isFunction( ready ) ) {
                                                        ready();
                                                }
-                                       }
-                                       // If any dependencies have errors execute error immediately
-                                       else if ( filter( ['error'], dependencies ).length ) {
+                                       } else if ( filter( ['error', 'missing'], dependencies ).length ) {
+                                               // Execute error immediately if any dependencies have errors
                                                if ( $.isFunction( error ) ) {
-                                                       error( new Error( 'one or more dependencies have state "error"' ),
+                                                       error( new Error( 'one or more dependencies have state "error" or "missing"' ),
                                                                dependencies );
                                                }
-                                       }
-                                       // Since some dependencies are not yet ready, queue up a request
-                                       else {
+                                       } else {
+                                               // Not all dependencies are ready: queue up a request
                                                request( dependencies, ready, error );
                                        }
                                },
-               
+
                                /**
                                 * Loads an external script or one or more modules for future use
                                 *
@@ -1225,7 +1289,7 @@ var mw = ( function ( $, undefined ) {
                                 *  be assumed if loading a URL, and false will be assumed otherwise.
                                 */
                                load: function ( modules, type, async ) {
-                                       var filtered, m;
+                                       var filtered, m, module;
 
                                        // Validate input
                                        if ( typeof modules !== 'object' && typeof modules !== 'string' ) {
@@ -1264,26 +1328,31 @@ var mw = ( function ( $, undefined ) {
                                        // an array of unrelated modules, whereas the modules passed to
                                        // using() are related and must all be loaded.
                                        for ( filtered = [], m = 0; m < modules.length; m += 1 ) {
-                                               if ( registry[modules[m]] !== undefined ) {
-                                                       filtered[filtered.length] = modules[m];
+                                               module = registry[modules[m]];
+                                               if ( module !== undefined ) {
+                                                       if ( $.inArray( module.state, ['error', 'missing'] ) === -1 ) {
+                                                               filtered[filtered.length] = modules[m];
+                                                       }
                                                }
                                        }
 
+                                       if (filtered.length === 0) {
+                                               return;
+                                       }
                                        // Resolve entire dependency map
                                        filtered = resolve( filtered );
-                                       // If all modules are ready, nothing dependency be done
-                                       if ( compare( filter( ['ready'], filtered ), filtered ) ) {
+                                       // If all modules are ready, nothing to be done
+                                       if ( allReady( filtered ) ) {
                                                return;
                                        }
-                                       // If any modules have errors
-                                       if ( filter( ['error'], filtered ).length ) {
+                                       // If any modules have errors: also quit.
+                                       if ( filter( ['error', 'missing'], filtered ).length ) {
                                                return;
                                        }
-                                       // Since some modules are not yet ready, queue up a request
+                                       // Since some modules are not yet ready, queue up a request.
                                        request( filtered, null, null, async );
-                                       return;
                                },
-               
+
                                /**
                                 * Changes the state of a module
                                 *
@@ -1302,7 +1371,8 @@ var mw = ( function ( $, undefined ) {
                                        if ( registry[module] === undefined ) {
                                                mw.loader.register( module );
                                        }
-                                       if ( state === 'ready' && registry[module].state !== state) {
+                                       if ( $.inArray(state, ['ready', 'error', 'missing']) !== -1
+                                               && registry[module].state !== state ) {
                                                // Make sure pending modules depending on this one get executed if their
                                                // dependencies are now fulfilled!
                                                registry[module].state = state;
@@ -1311,7 +1381,7 @@ var mw = ( function ( $, undefined ) {
                                                registry[module].state = state;
                                        }
                                },
-               
+
                                /**
                                 * Gets the version of a module
                                 *
@@ -1323,14 +1393,14 @@ var mw = ( function ( $, undefined ) {
                                        }
                                        return null;
                                },
-               
+
                                /**
                                 * @deprecated since 1.18 use mw.loader.getVersion() instead
                                 */
                                version: function () {
                                        return mw.loader.getVersion.apply( mw.loader, arguments );
                                },
-               
+
                                /**
                                 * Gets the state of a module
                                 *
@@ -1342,7 +1412,7 @@ var mw = ( function ( $, undefined ) {
                                        }
                                        return null;
                                },
-               
+
                                /**
                                 * Get names of all registered modules.
                                 *
@@ -1353,7 +1423,7 @@ var mw = ( function ( $, undefined ) {
                                                return key;
                                        } );
                                },
-               
+
                                /**
                                 * For backwards-compatibility with Squid-cached pages. Loads mw.user
                                 */
@@ -1362,7 +1432,7 @@ var mw = ( function ( $, undefined ) {
                                }
                        };
                }() ),
-       
+
                /** HTML construction helper functions */
                html: ( function () {
                        function escapeCallback( s ) {
@@ -1388,7 +1458,7 @@ var mw = ( function ( $, undefined ) {
                                escape: function ( s ) {
                                        return s.replace( /['"<>&]/g, escapeCallback );
                                },
-               
+
                                /**
                                 * Wrapper object for raw HTML passed to mw.html.element().
                                 * @constructor
@@ -1396,7 +1466,7 @@ var mw = ( function ( $, undefined ) {
                                Raw: function ( value ) {
                                        this.value = value;
                                },
-               
+
                                /**
                                 * Wrapper object for CDATA element contents passed to mw.html.element()
                                 * @constructor
@@ -1404,7 +1474,7 @@ var mw = ( function ( $, undefined ) {
                                Cdata: function ( value ) {
                                        this.value = value;
                                },
-               
+
                                /**
                                 * Create an HTML element string, with safe escaping.
                                 *
@@ -1426,7 +1496,7 @@ var mw = ( function ( $, undefined ) {
                                 */
                                element: function ( name, attrs, contents ) {
                                        var v, attrName, s = '<' + name;
-               
+
                                        for ( attrName in attrs ) {
                                                v = attrs[attrName];
                                                // Convert name=true, to name=name
@@ -1481,7 +1551,7 @@ var mw = ( function ( $, undefined ) {
                        tokens: new Map()
                }
        };
-       
+
 }( jQuery ) );
 
 // Alias $j to jQuery for backwards compatibility