Bug 1530402 introduced support for the browser/page action extension APIs. They have mostly been hooked up. One of the methods, the openPopup method has not correctly been hooked up in A-C, despite the method being supported in GeckoView (unit test: ExtensionActionTest.kt), and supported in TestRunnerActivity (source) and GVE (source).

This report shows the STR and provides guidance on supporting the functionality in A-C / Fenix.

Steps to reproduce

This can manually be confirmed on current Firefox for Android builds:

1. Install uBlock Origin (that has a browserAction popup).
2. Attach a debugger (enabling ADB debugging, enabling remote debugging in the Firefox app and then via about:debugging on desktop)
3. Open any tab (e.g. example.com) to launch the Gecko process.
4. Ensure that we can call browser.browserAction.openPopup. This currently requires a user gesture (until bug 1799344 removes that requirement). There are three ways to meet this requirement:

• Set the extensions.openPopupWithoutUserGesture.enabled preference to true,
  • via the instructions at https://firefox-source-docs.mozilla.org/mobile/android/geckoview/consumer/automation.html
  • or by inspecting the main process via about:debugging (from step 2) and running Services.prefs.setBoolPref("extensions.openPopupWithoutUserGesture.enabled", true) (if this is your main profile, revert this when you're done by running Services.prefs.clearUserPref("extensions.openPopupWithoutUserGesture.enabled")
• Or by opening an extension page, registering a click event listener and call the openPopup method from the click handler,
• Inspect the extension and call browser.tabs.create({ url: browser.runtime.getURL("manifest.json") }) to open a new extension tab.
• Inspect that tab in the devtools, and register the listener: document.body.onclick = () => { browser.browserAction.openPopup(); };.
• Interact with the browser manually by tapping in the content area of the tab.

5. Once you have enabled the openPopup API (step 4), open the popup by calling browser.browserAction.openPopup(); (e.g. via the devtools).

Expected behavior

• The extension popup opens.

Actual behavior

• Nothing happens.

Implementation details

To support it on Fenix:

• A-C: Add an onOpenPopup override at https://github.com/mozilla-mobile/firefox-android/blob/9de5ab8cc098674aad5190ce8b00ae6be65e9bd0/android-components/components/browser/engine-gecko/src/main/java/mozilla/components/browser/engine/gecko/webextension/GeckoWebExtension.kt#L177-L204
  • The implementation should show the popup if it was not visible, and be no-op if it was visible (or reject the call with an error; in this case GeckoView would need to be updated to handle the error).
  • Along with the changes in A-C, whatever that's needed to actually hook it up in Fenix.
• Add a unit test at https://github.com/mozilla-mobile/firefox-android/blob/9de5ab8cc098674aad5190ce8b00ae6be65e9bd0/android-components/components/browser/engine-gecko/src/test/java/mozilla/components/browser/engine/gecko/webextension/GeckoWebExtensionTest.kt#L259

Additional notes:

• It would be really nice to be able to open the popup for arbitrary "windows" (tabs / GeckoSession), and not to assume it to be whatever the currently active tab is. That should be fixed along with bug 1817772 (see also: https://bugzilla.mozilla.org/show_bug.cgi?id=1795956#c1 ).
• Not a must-have, but if possible, it would be nice to notify GeckoView/Gecko when the popup has finally been opened (to support bug 1811071).

This would be a good-first-bug for WebExtension engineers who are looking to contribute to Android-Components / Fenix.

Not a must-have, but if possible, it would be nice to notify GeckoView/Gecko when the popup has finally been opened (to support bug 1811071).