1394019 - TypeError: this.browser is null in ExtensionPopups.jsm when extension popup is closed on load

Status: VERIFIED FIXED

(WebExtensions :: Frontend, defect, P3)

Description

[Rob Wu [:robwu]]

Attachment: synchronously.zip

STR
1. Load attached extension (extract synchronously.zip to a directory and load the extension at about:debugging).
2. Click on the extension button (it has tooltip "Close synchronously during script execution").
3. Look at the global JS console (Ctrl-Shift-J).

Expected:
- No errors

Actual:
- TypeError: this.browser is null
  at the Promise callback in unblockParser in https://searchfox.org/mozilla-central/rev/5696c3e525fc8222674eed6a562f5fcbe804c4c7/browser/components/extensions/ExtensionPopups.jsm#320

Easy fix:
- Test whether this.browser is null before using this.browser.

Comment 1

[Rob Wu [:robwu]]

Attachment: domcontentloaded.zip

Same extension, except it calls window.close() at the DOMContentLoaded event instead of while the script is initializing.

Same expectation, same actual result.

This concludes the test cases for closing the extension popup during load, there is also error spam when an extension popup mutates the DOM during unload - see bug 1394010.

Comment 2

[Trishul]

Test case -
install Cliqz extension from AMO, open browser action and click close button in the popup
Following error is observed in console:
TypeError: can't access property "ownerGlobal", browser is null in BrowserElementParent.jsm:81:21

This happens whenever window.close() is called from script within browser action popup.

Comment 3

[Rob Wu [:robwu]]

I can reproduce the error from comment 2 in Firefox 69 - 74. The error points to https://searchfox.org/mozilla-central/rev/c52d5f8025b5c9b2b4487159419ac9012762c40c/toolkit/actors/BrowserElementParent.jsm#81

In Firefox 68, the test case from the initial report does not trigger any errors. The new error is probably due to the change in bug 1533949 . If I add event.stopPropagation() at https://searchfox.org/mozilla-central/rev/c52d5f8025b5c9b2b4487159419ac9012762c40c/toolkit/components/extensions/ext-browser-content.js#161 , then the error message isn't printed any more.

There is also another error message when the popup is closed (or when the mouse pointer hovers above the extension button and then away):

[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIControllers.removeController]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: chrome://global/content/elements/browser-custom-element.js :: destroy :: line 1374" data: no]

There doesn't seem to be any bad side effects besides these errors.

Comment 4

[Trishul]

Hi Rob, so what do you suggest,
shall we go ahead and subside the error with event.stopPropagation() ?
I also can not find anything breaking

Comment 5

[Rob Wu [:robwu]]

I would suggest to either update the condition at https://searchfox.org/mozilla-central/rev/803a42f24c8714631ed81cb824ea1c1a803cb7b8/toolkit/actors/BrowserElementChild.jsm#13

or if that is not feasible, change the implementation to avoid the error at https://searchfox.org/mozilla-central/rev/803a42f24c8714631ed81cb824ea1c1a803cb7b8/toolkit/actors/BrowserElementParent.jsm#81

Comment 6

[Trishul]

Attachment: Bug 1394019: TypeError: this.browser is null

TypeError: this.browser is null

Comment 7

[Trishul]

Hi Rob, may be this would be enough to subside the error.

Comment 8

[Rob Wu [:robwu]]

Attachment: Bug 1394019 - Handle DOMWindowClose of extension popup in parent

Starting from bug 1394019, the DOMWindowClose event is forwarded to the
<browser> element, so there is no need for a custom
"Extension:DOMWindowClose" message any more.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c7d802a739c6
Handle DOMWindowClose of extension popup in parent r=zombie

Comment 10

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/c7d802a739c6

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/251268cf2381
Port bug 1394019 - Handle DOMWindowClose of extension popup in parent. rs=bustage-fix

Comment 12

[Miruna Curtean]

Verified fixed on Windows pro 10 64-bit and MacOS Catalina 10.15 on FF Nightly 75.0a1 (20200213035745) using extensions from description, comment 1 and comment 2. TypeError: browser is null error is no longer received in browser console.