Bug 1869896 - Put automatic restart behind Nimbus experiment r=nalexander,application-update-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D196483

.eslintignore

@@ -188,6 +188,8 @@ mobile/android/locales/
 modules/libpref/greprefs.js
 modules/libpref/init/all.js
 modules/libpref/test/unit/*data/
+toolkit/components/backgroundtasks/defaults/backgroundtasks.js
+toolkit/components/backgroundtasks/defaults/backgroundtasks_browser.js
 
 # Only contains non-standard test files.
 python/

.prettierignore

@@ -1161,6 +1161,8 @@ mobile/android/locales/
 modules/libpref/greprefs.js
 modules/libpref/init/all.js
 modules/libpref/test/unit/*data/
+toolkit/components/backgroundtasks/defaults/backgroundtasks.js
+toolkit/components/backgroundtasks/defaults/backgroundtasks_browser.js
 
 # Only contains non-standard test files.
 python/

toolkit/components/backgroundtasks/defaults/backgroundtasks.js

@@ -2,6 +2,8 @@
  * 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/. */
 
+#filter substitution;
+
 // These preferences override Gecko preferences in `greprefs.js`.  Use
 // `backgroundtasks_browser.js` to override browser/-specific preferences in
 // `firefox.js`.
@@ -45,3 +47,10 @@ pref("security.nocertdb", true);
 
 // Prevent asynchronous preference writes.
 pref("preferences.allow.omt-write", false);
+
+// Enable automatic restarts during background updates for Nightly builds.
+#ifdef NIGHTLY_BUILD
+pref("app.update.background.automaticRestartEnabled", true);
+#else
+pref("app.update.background.automaticRestartEnabled", false);
+#endif

toolkit/components/backgroundtasks/defaults/backgroundtasks_browser.js

@@ -2,6 +2,8 @@
  * 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/. */
 
+#filter substitution;
+
 // These preferences override override browser/-specific preferences in
 // `firefox.js`.  Use `backgroundtasks.js` to override general Gecko preferences
 // in `greprefs.js`.

toolkit/components/backgroundtasks/moz.build

@@ -91,11 +91,11 @@ if CONFIG["MOZ_BUILD_APP"] == "browser":
         "tests/BackgroundTask_targeting.sys.mjs",
     ]
 
-    FINAL_TARGET_FILES.browser.defaults.backgroundtasks += [
+    FINAL_TARGET_PP_FILES.browser.defaults.backgroundtasks += [
         "defaults/backgroundtasks_browser.js",
     ]
 
-FINAL_TARGET_FILES.defaults.backgroundtasks += [
+FINAL_TARGET_PP_FILES.defaults.backgroundtasks += [
     "defaults/backgroundtasks.js",
 ]
 

toolkit/components/nimbus/FeatureManifest.yaml

@@ -1172,6 +1172,23 @@ backgroundTaskMessage:
     path: "browser/components/newtab/content-src/asrouter/schemas/BackgroundTaskMessagingExperiment.schema.json"
   variables: {}
 
+backgroundUpdateAutomaticRestart:
+  description: "Whether to automatically restart when the background update task could make more progress."
+  owner: nalexander@mozilla.com
+  applications:
+    - firefox-desktop-background-task
+  hasExposure: false
+  isEarlyStartup: false
+  variables:
+    enabled:
+      type: boolean
+      fallbackPref: app.update.background.automaticRestartEnabled
+      description: >-
+        When true, make the background update task restart when the final update state is `READY_FOR_RESTART`.
+        Generally, this will finish applying a staged update, completing the update earlier than it
+        otherwise would have been completed.
+
+
 pictureinpicture:
   description: Message for first time Picture-in-Picture users
   owner: nbaumgardner@mozilla.com

toolkit/mozapps/update/BackgroundTask_backgroundupdate.sys.mjs

@@ -17,6 +17,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
   AppUpdater: "resource://gre/modules/AppUpdater.sys.mjs",
   BackgroundTasksUtils: "resource://gre/modules/BackgroundTasksUtils.sys.mjs",
   ExtensionUtils: "resource://gre/modules/ExtensionUtils.sys.mjs",
+  NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
   UpdateUtils: "resource://gre/modules/UpdateUtils.sys.mjs",
 });
 
@@ -436,6 +437,9 @@ export async function runBackgroundTask(commandLine) {
   );
   // If a restart loop is occurring then automaticRestartFound will be true.
   if (
+    lazy.NimbusFeatures.backgroundUpdateAutomaticRestart.getVariable(
+      "enabled"
+    ) &&
     updateStatus === lazy.AppUpdater.STATUS.READY_FOR_RESTART &&
     !automaticRestartFound
   ) {