2069995 - Intermittent toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | single tracking bug

Status: RESOLVED FIXED

(Firefox :: PDF Viewer, defect, P1)

Description

[Treeherder Bug Filer]

Filed by: asilaghi [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer?job_id=590891703&repo=autoland&task=YSKjYf9SRayn_74D0WC87w.0
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/YSKjYf9SRayn_74D0WC87w/runs/0/artifacts/public/logs/live_backing.log
Reftest URL: https://hg.mozilla.org/mozilla-central/raw-file/default/layout/tools/reftest/reftest-analyzer.xhtml#logurl=https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/YSKjYf9SRayn_74D0WC87w/runs/0/artifacts/public/logs/live_backing.log&only_show_unexpected=1

---

[task 2026-09-07T16:55:00.859+00:00] 16:55:00     INFO - TEST-PASS | toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | test_only_frames_embedded_in_pages_are_opened - The PDF is in an object
[task 2026-09-07T16:55:00.860+00:00] 16:55:00     INFO - TEST-PASS | toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | test_only_frames_embedded_in_pages_are_opened - The PDF embedded with an object must be loaded
[task 2026-09-07T16:55:00.860+00:00] 16:55:00     INFO - Leaving test test_only_frames_embedded_in_pages_are_opened
[task 2026-09-07T16:55:00.860+00:00] 16:55:00     INFO - Entering test test_fallback_hidden_when_embed_is_too_short
[task 2026-09-07T16:55:00.860+00:00] 16:55:00     INFO - TEST-PASS | toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | test_fallback_hidden_when_embed_is_too_short - The embed element must have a browsing context
[task 2026-09-07T16:55:00.860+00:00] 16:55:00     INFO - Buffered messages finished
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - TEST-UNEXPECTED-FAIL | toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | test_fallback_hidden_when_embed_is_too_short - The fallback must be hidden when its complete UI cannot be shown - "flex" == "none" - got "flex", expected "none" (operator ==)
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - is@resource://testing-common/SpecialPowersSandbox.sys.mjs:88:21
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - @chrome://mochitests/content/browser/toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js:596:7
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - execute@resource://testing-common/SpecialPowersSandbox.sys.mjs:139:12
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - _spawnTask@resource://testing-common/SpecialPowersChild.sys.mjs:1625:15
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - receiveMessage@resource://testing-common/SpecialPowersChild.sys.mjs:254:21
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - JSActor query*receiveMessage@resource://testing-common/SpecialPowersParent.sys.mjs:1377:14
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - JSActor query*spawn@resource://testing-common/SpecialPowersChild.sys.mjs:1552:17
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - test_fallback_hidden_when_embed_is_too_short@chrome://mochitests/content/browser/toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js:593:23
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - async*handleTask@chrome://mochikit/content/browser-test.js:1526:26
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - _runTaskBasedTest@chrome://mochikit/content/browser-test.js:1616:18
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - async*Tester_execTest@chrome://mochikit/content/browser-test.js:1769:14
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - nextTest/<@chrome://mochikit/content/browser-test.js:1500:14
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - SimpleTest.waitForFocus/<@chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:1060:13
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - promise callback*SimpleTest.waitForFocus@chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:1059:53
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - nextTest@chrome://mochikit/content/browser-test.js:1405:21
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - async*testScope/test_finish/<@chrome://mochikit/content/browser-test.js:2256:25
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - run@chrome://mochikit/content/browser-test.js:2179:9
[task 2026-09-07T16:55:00.861+00:00] 16:55:00     INFO - Leaving test test_fallback_hidden_when_embed_is_too_short
[task 2026-09-07T16:55:00.862+00:00] 16:55:00     INFO - Entering test test_open_pdf_preserves_referrer
[task 2026-09-07T16:55:00.862+00:00] 16:55:00     INFO - TEST-PASS | toolkit/components/pdfjs/test/browser_pdfjs_embed_fallback.js | test_open_pdf_preserves_referrer - The embed element must have a browsing context

Comment 1

[BugBot [:suhaib / :marco]]

:calixte, since you are the author of the regressor, bug 2049760, could you take a look?

For more information, please visit BugBot documentation.

Comment 2

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 2049760

Comment 3

[Calixte Denizet (:calixte)]

Attachment: Bug 2069995 - Wait until the short embedded PDF fallback is hidden. r?marco

The fallback load event can fire before its viewport is updated to the embed size. Wait for its computed display to become "none" rather than checking immediately.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/f7410bb9aa21
https://hg.mozilla.org/integration/autoland/rev/b305fa8cbc5c
Wait until the short embedded PDF fallback is hidden. r=marco

Comment 5

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 2049760

Comment 6

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/b305fa8cbc5c

Comment 7

[Intermittent Failures Robot]

7 failures were associated with this bug in the last 7 days.

Repository breakdown:

• autoland: 2
• mozilla-central: 5

Table

	a11y_checks+swgl	no-nv	no_variant	standalone	swgl
linux2404-x86_64/opt			1
macosx1500-aarch64/opt		4	2

For more details, see:

https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=2069995&startday=2026-09-07&endday=2026-09-13&tree=all