2005471 - Going back from a Reddit image preview skips 1 page with Navigation API enabled

Status: VERIFIED FIXED

(Core :: DOM: Navigation, defect)

Description

[Fanolian]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:148.0) Gecko/20100101 Firefox/148.0
Build ID: 20251210095635

Steps to reproduce

1. Enable Navigation API on Nightly.
2. Go to any page to create a dummy tab history. E.g. https://www.firefox.com/en-US/.
3. In the same tab, go to any Reddit page with an image that can be clicked to preview. E.g. https://www.reddit.com/r/aww/hot/ (P.S. not old.reddit.com version)
4. Left-click an image to pop up a preview lightbox.
5. With the preview still opened, go back 1 page.
6. [Optional] Go forward 1 page.

Actual result

The tab goes back to https://www.firefox.com/en-US/, not https://www.reddit.com/r/aww/hot/.
Navigating forward at step 6 brings me back to https://www.reddit.com/r/aww/hot/.

Expected result

The tab should go back to https://www.reddit.com/r/aww/hot/ at step 5.

Additional notes

Clicking the cross button on the top right corner of the lightbox brings me back to https://www.reddit.com/r/aww/hot/ as expected.

If there is no previous histories on the tab, i.e. open a new tab -> go to reddit to click on an image -> click back, the tab goes back to https://www.reddit.com/r/aww/hot/ as expected.

Workaround

Set dom.navigation.webidl.enabled to false.

Regression

Last good Nightly: 2025-10-31
First bad Nightly: 2025-11-01
pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=90470f1361431a99abb4526828c12b7adc2296cb&tochange=3befa2ffc228fd4d071c8b696872a760954392fc

Bisecting autoland builds:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=90470f1361431a99abb4526828c12b7adc2296cb&tochange=86a3463c7d95316b2905a2d45caa3a14d843a5a5

This is regressed by bug 1979288.

Comment 1

[Fanolian]

If there is no previous histories on the tab, i.e. open a new tab -> go to reddit to click on an image -> click back, the tab goes back to https://www.reddit.com/r/aww/hot/ as expected.

Please disregard this part. The bug still exhibits with the steps above. I forgot to turn Navigation API back on.

Comment 2

[Ryan VanderMeulen (PTO, back 6-April)]

Hi Fanolian, is this still reproducing for you with current Nightly builds? We've landed some fixes that were supposed to address Reddit navigation issues.

Comment 3

[Jan Jaeschke [:jjaschke]]

Not this one though. We have a patch, :farre will post it tomorrow.

Comment 4

[Andreas Farre [:farre]]

Attachment: Bug 2005471 - Abort history traversal to identical entry. r=smaug!

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/ff7376054bcd
https://hg.mozilla.org/integration/autoland/rev/6f12f1dfb0a6
Abort history traversal to identical entry. r=smaug

Comment 6

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/56813 for changes under testing/web-platform/tests

Comment 7

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/6f12f1dfb0a6

Comment 8

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 9

[Ryan VanderMeulen (PTO, back 6-April)]

Please nominate this Beta uplift when you get a chance.

Comment 10

[Andreas Farre [:farre]]

Attachment: Bug 2005471 - Abort history traversal to identical entry.

Original Revision: https://phabricator.services.mozilla.com/D276815

Comment 11

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined: Reddit #lightbox (image preview) is broken
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: * Go to reddit.com/aww/hot

• Click an image to get the preview
• Press back (in UI)
• Verify that we return to reddit.com/aww/hot

• Risk associated with taking this patch: low
• Explanation of risk level: Small and contained change
• String changes made/needed: None
• Is Android affected?: yes

Comment 12

[Andreas Farre [:farre]]

(In reply to Ryan VanderMeulen [:RyanVM] from comment #9)

Please nominate this Beta uplift when you get a chance.

Done, thanks for the poke. Wanted it to simmer at least a full day on central.

Comment 13

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/dc31eaa8eb9b
https://hg.mozilla.org/releases/mozilla-beta/rev/922085d12de1

Comment 14

[Ciprian Georgiu, Desktop QA]

I reproduced this issue on Win 11 using an affected Nightly build (2025-12-11) following the STR from comment 0.

The issue is verified as fixed on latest Beta 147.0b7 (build downloaded from treeherder) and Nightly 148.0a1 under Win 11, macOS 26.1 and Ubuntu 24.