+++ This bug was initially created as a clone of Bug #1359021 +++

It only happens when open popup from file: protocol.

alternative steps to reproduce:
0. Save https://bugzilla.mozilla.org/attachment.cgi?id=8860901 to local file system

1. Make sure e10s enabled
2. Open the saved html with file:// protocol
3. Click [open popup] button
4. Repeat step.3

Actual Results:
Popup windows are opened in duplicate

Expected Results:
Pop-up windows should be reused if same target name.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=b0e84820d231a3b5a47f2ea72c384828d91f4c49&tochange=b158903288bb2968dff9e587a3a8ca67f7435e37

[Tracking Requested - why for this release]:
Rather bad regression for anyone using file:// urls.

The priority flag is not set for this bug.
:farre, could you have a look please?

For more information, please visit auto_nag documentation.

Hi Paul, are you still planning to resolve this one for 77?

The patches in Bug 1634779 fix the problem. I'm writing a regression test now to make sure this doesn't happen again.

Reproduced the issue on Firefox 77.0a1 (20200419091145) on Windows 10 and Ubuntu 18.04.4.
Verified fixed on Firefox 77.0b9 (20200521224544). This is also Verified fixed on Firefox 78.0a1 (20200521093657) .

Depends on D76096

Backed out for failures on browser_multiselect_tabs_move_to_another_window_drag.js

backout: https://hg.mozilla.org/integration/autoland/rev/9c1b2859111c0b84b8a1112dd3b36bd5910376e1

push: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&searchStr=browser-chrome&revision=f7663b8964e9a0fb52e2e4fdd0ac84772e6c97e7&selectedTaskRun=E3o9jYqbQn6Eq4v3ZRL5mw-0

failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=304679021&repo=autoland&lineNumber=9457

[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - TEST-PASS | browser/base/content/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js | Tab3 and tab5 are duplicated succesfully -
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - Leaving test bound test
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - Buffered messages finished
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js | A promise chain failed to handle a rejection: (Unable to convert rejection reason to string.) - stack: observe@resource://testing-common/BrowserTestUtils.jsm:798:19
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - asyncreplaceTabWithWindow@chrome://browser/content/tabbrowser.js:4353:21
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - replaceTabsWithWindow@chrome://browser/content/tabbrowser.js:4399:22
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - test@chrome://mochitests/content/browser/browser/base/content/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js:23:28
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - AsyncTester_execTest/<@chrome://mochikit/content/browser-test.js:1064:34
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - Tester_execTest@chrome://mochikit/content/browser-test.js:1104:11
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - nextTest/<@chrome://mochikit/content/browser-test.js:927:14
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - SimpleTest.waitForFocus/waitForFocusInner/focusedOrLoaded/<@chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:918:23
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - Rejection date: Tue Jun 02 2020 05:01:23 GMT+0000 (Greenwich Mean Time) - false == true - JS frame :: resource://testing-common/PromiseTestUtils.jsm :: assertNoUncaughtRejections :: line 265
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - Stack trace:
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - resource://testing-common/PromiseTestUtils.jsm:assertNoUncaughtRejections:265
[task 2020-06-02T05:01:23.361Z] 05:01:23 INFO - chrome://mochikit/content/browser-test.js:nextTest:610
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - chrome://mochikit/content/browser-test.js:testScope/test_finish/<:1464
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - chrome://mochikit/content/browser-test.js:run:1379
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - GECKO(4456) | JavaScript error: resource://testing-common/BrowserTestUtils.jsm, line 798: uncaught exception: undefined
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - Console message: [JavaScript Error: "uncaught exception: undefined" {file: "resource://testing-common/BrowserTestUtils.jsm" line: 798}]
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - GECKO(4456) | MEMORY STAT | vsize 2104431MB | vsizeMaxContiguous 65850462MB | residentFast 389MB | heapAllocated 145MB
[task 2020-06-02T05:01:23.362Z] 05:01:23 INFO - TEST-OK | browser/base/content/test/tabs/browser_multiselect_tabs_move_to_another_window_drag.js | took 4606ms

Really? I get the same failure on central.

Hi Paul,

I took a look on central on the browser-chrome failures but I didn't manage to spot any just like the one mentioned in the backout https://treeherder.mozilla.org/#/jobs?repo=mozilla-central&group_state=expanded&searchStr=browser-chrome . Could you pin-point me to one of them as an example?

Thank you.

No worries Natalia, I found the problem. I didn't know that a problem in my test could affect other tests in this way. Sorry to bother you with this.

https://hg.mozilla.org/mozilla-central/rev/cf0703e56c9f

The patch landed in nightly and beta is affected.
:pbone, is this bug important enough to require an uplift?
If not please set status_beta to wontfix.

For more information, please visit auto_nag documentation.

The fix already landed in beta, this patch includes a test only.

Thanks.