Bug 1353542 - Add an eslint rule deprecating usage of Task.jsm in browser/ and toolkit/, r=Mossop.

browser/.eslintrc.js

@@ -25,5 +25,7 @@ module.exports = {
 
     "no-mixed-spaces-and-tabs": "error",
     "no-shadow": "error",
+
+    "mozilla/no-task": "error",
   }
 };

browser/base/content/test/general/browser_e10s_chrome_process.js

@@ -21,8 +21,7 @@ function makeTest(name, startURL, startProcessIsRemote, endURL, endProcessIsRemo
     is(browser.isRemoteBrowser, startProcessIsRemote, "Should be displayed in the right process");
 
     let docLoadedPromise = waitForDocLoadComplete();
-    let asyncTask = Task.async(transitionTask);
-    let expectSyncChange = await asyncTask(browser, endURL);
+    let expectSyncChange = await transitionTask(browser, endURL);
     if (expectSyncChange) {
       is(browser.isRemoteBrowser, endProcessIsRemote, "Should have switched to the right process synchronously");
     }

browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Buttons.jsm

@@ -19,21 +19,21 @@ this.Buttons = {
 
   configurations: {
     navBarButtons: {
-      applyConfig: Task.async(() => {
+      applyConfig: async () => {
         CustomizableUI.addWidgetToArea("screenshot-widget", CustomizableUI.AREA_NAVBAR);
-      }),
+      },
     },
 
     tabsToolbarButtons: {
-      applyConfig: Task.async(() => {
+      applyConfig: async () => {
         CustomizableUI.addWidgetToArea("screenshot-widget", CustomizableUI.AREA_TABSTRIP);
-      }),
+      },
     },
 
     menuPanelButtons: {
-      applyConfig: Task.async(() => {
+      applyConfig: async () => {
         CustomizableUI.addWidgetToArea("screenshot-widget", CustomizableUI.AREA_PANEL);
-      }),
+      },
 
       verifyConfig() {
         let browserWindow = Services.wm.getMostRecentWindow("navigator:browser");
@@ -45,9 +45,9 @@ this.Buttons = {
     },
 
     custPaletteButtons: {
-      applyConfig: Task.async(() => {
+      applyConfig: async () => {
         CustomizableUI.removeWidgetFromArea("screenshot-widget");
-      }),
+      },
 
       verifyConfig() {
         let browserWindow = Services.wm.getMostRecentWindow("navigator:browser");

toolkit/.eslintrc.js

@@ -9,5 +9,7 @@ module.exports = {
     // XXX Bug 1326071 - This should be reduced down - probably to 20 or to
     // be removed & synced with the mozilla/recommended value.
     "complexity": ["error", 41],
+
+    "mozilla/no-task": "error",
   }
 };

toolkit/components/thumbnails/test/browser_thumbnails_storage.js

@@ -18,19 +18,19 @@ XPCOMUtils.defineLazyGetter(this, "Sanitizer", function() {
  * be removed when the user sanitizes their history.
  */
 function* runTests() {
-  yield Task.spawn(function*() {
+  yield (async function() {
     dontExpireThumbnailURLs([URL, URL_COPY]);
 
-    yield promiseClearHistory();
-    yield promiseAddVisitsAndRepopulateNewTabLinks(URL);
-    yield promiseCreateThumbnail();
+    await promiseClearHistory();
+    await promiseAddVisitsAndRepopulateNewTabLinks(URL);
+    await promiseCreateThumbnail();
 
     // Make sure Storage.copy() updates an existing file.
-    yield PageThumbsStorage.copy(URL, URL_COPY);
+    await PageThumbsStorage.copy(URL, URL_COPY);
     let copy = new FileUtils.File(PageThumbsStorage.getFilePathForURL(URL_COPY));
     let mtime = copy.lastModifiedTime -= 60;
 
-    yield PageThumbsStorage.copy(URL, URL_COPY);
+    await PageThumbsStorage.copy(URL, URL_COPY);
     isnot(new FileUtils.File(PageThumbsStorage.getFilePathForURL(URL_COPY)).lastModifiedTime, mtime,
           "thumbnail file was updated");
 
@@ -41,37 +41,37 @@ function* runTests() {
     // locks them sometimes.
     info("Clearing history");
     while (file.exists() || fileCopy.exists()) {
-      yield promiseClearHistory();
+      await promiseClearHistory();
     }
     info("History is clear");
 
     info("Repopulating");
-    yield promiseAddVisitsAndRepopulateNewTabLinks(URL);
-    yield promiseCreateThumbnail();
+    await promiseAddVisitsAndRepopulateNewTabLinks(URL);
+    await promiseCreateThumbnail();
 
     info("Clearing the last 10 minutes of browsing history");
     // Clear the last 10 minutes of browsing history.
-    yield promiseClearHistory(true);
+    await promiseClearHistory(true);
 
     info("Attempt to clear file");
     // Retry until the file is gone because Windows locks it sometimes.
-    yield promiseClearFile(file, URL);
+    await promiseClearFile(file, URL);
 
     info("Done");
-  });
+  })();
 }
 
-var promiseClearFile = Task.async(function*(aFile, aURL) {
+async function promiseClearFile(aFile, aURL) {
   if (!aFile.exists()) {
     return undefined;
   }
   // Re-add our URL to the history so that history observer's onDeleteURI()
   // is called again.
-  yield PlacesTestUtils.addVisits(makeURI(aURL));
-  yield promiseClearHistory(true);
+  await PlacesTestUtils.addVisits(makeURI(aURL));
+  await promiseClearHistory(true);
   // Then retry.
   return promiseClearFile(aFile, aURL);
-});
+}
 
 function promiseClearHistory(aUseRange) {
   let s = new Sanitizer();

toolkit/modules/Sqlite.jsm

@@ -592,7 +592,7 @@ ConnectionData.prototype = Object.freeze({
           try {
             // Keep Task.spawn here to preserve API compat; unfortunately
             // func was a generator rather than a task here.
-            result = await Task.spawn(func);
+            result = await Task.spawn(func); // eslint-disable-line mozilla/no-task
           } catch (ex) {
             // It's possible that the exception has been caused by trying to
             // close the connection in the middle of a transaction.

toolkit/modules/Task.jsm

@@ -6,6 +6,8 @@
 
 "use strict";
 
+/* eslint-disable mozilla/no-task */
+
 this.EXPORTED_SYMBOLS = [
   "Task"
 ];

toolkit/modules/tests/xpcshell/test_Promise.js

@@ -550,7 +550,7 @@ tests.push(
 // Test that Promise.resolve throws when its argument is an async function.
 tests.push(
   make_promise_test(function test_promise_resolve_throws_with_async_function(test) {
-    Assert.throws(() => Promise.resolve(Task.async(function* () {})),
+    Assert.throws(() => Promise.resolve(Task.async(function* () {})), // eslint-disable-line mozilla/no-task
                   /Cannot resolve a promise with an async function/);
     return Promise.resolve();
   }));

tools/lint/eslint/eslint-plugin-mozilla/lib/index.js

@@ -46,6 +46,7 @@ module.exports = {
     "no-single-arg-cu-import": require("../lib/rules/no-single-arg-cu-import"),
     "no-import-into-var-and-global":
       require("../lib/rules/no-import-into-var-and-global.js"),
+    "no-task": require("../lib/rules/no-task"),
     "no-useless-parameters": require("../lib/rules/no-useless-parameters"),
     "no-useless-removeEventListener":
       require("../lib/rules/no-useless-removeEventListener"),
@@ -70,6 +71,7 @@ module.exports = {
     "no-cpows-in-tests": "off",
     "no-single-arg-cu-import": "off",
     "no-import-into-var-and-global": "off",
+    "no-task": "off",
     "no-useless-parameters": "off",
     "no-useless-removeEventListener": "off",
     "reject-importGlobalProperties": "off",

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-task.js

@@ -0,0 +1,31 @@
+/**
+ * @fileoverview Reject common XPCOM methods called with useless optional
+ *               parameters, or non-existent parameters.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  return {
+    "CallExpression": function(node) {
+      let callee = node.callee;
+      if (callee.type === "MemberExpression" &&
+          callee.object.type === "Identifier" &&
+          callee.object.name === "Task") {
+        context.report({node, message: "Task.jsm is deprecated."});
+      }
+    }
+  };
+};