1666670 - beforeunload doesn't prevent closing a tab (or window, or quitting Firefox)

Status: VERIFIED FIXED

(Core :: DOM: Navigation, defect, P2)

Description

[Adam Gashlin (he/him) [:agashlin] (ex-moco)]

Attachment: unloadtest.html

STR:

1. Navigate to the attached page (just sets up a beforeunload listener with preventDefault)
2. Click somewhere in the client area to allow it to prevent nagivation
3. Close the tab

Expected:

"This page is asking you to confirm..." dialog appears, preventing the tab from closing.

Actual:

Dialog appears, but before any interaction (~1 sec) the tab closes anyway.

Seen on Windows 10 64 bit, with a clean profile.

Regression range from mozregression:

Last good revision: c0db57c7f9f0d7df1fcb3e7afcd823256c9bbe6b
First bad revision: 091a4043d78af274fd5639829f17e4195d262e4a
Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c0db57c7f9f0d7df1fcb3e7afcd823256c9bbe6b&tochange=091a4043d78af274fd5639829f17e4195d262e4a

This seems to point to bug 1655866, which involves beforeunload.

(apologies if I've misunderstood and this is now intended)

Comment 1

[:Gijs (he/him)]

[Tracking Requested - why for this release]:
This also affects quitting or closing the entire window, and some of our users' web apps will be relying on these prompts to prevent user dataloss. We shouldn't ship with this.

Comment 2

[Kris Maglione [:kmag]]

Attachment: Bug 1666670: Fix beforeunload timeout handling to ignore prompt. r=mconley

Comment 3

[Neha Kochar [:neha]]

Not a Fission-only issue.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6cf959e2de7b
Fix beforeunload timeout handling to ignore prompt. r=mconley

Comment 6

[Narcis Beleuzu [:NarcisB]]

Backed out for wpt failures on scroll-behavior-smooth.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/ffb52170db5c5cdbe24093c0c39e05becd23c130
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=317238320&repo=autoland&lineNumber=1930

Comment 7

[Kris Maglione [:kmag]]

There's no plausible way that WPT failure was caused by my patch.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/290e7f47eed9
Fix beforeunload timeout handling to ignore prompt. r=mconley

Comment 10

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/290e7f47eed9

Comment 11

[Alin Ilea, Desktop Test Engineering [pto until 01.09]]

Reproduced the initial issue in Nightly 83.0a1 (build id: 20200922094538) using Windows 10.
Verified - Fixed in latest Nightly 84.0a1 (2020-10-22) and Beta 83.0b3 (build id: 20201022171613) on Windows 10 and Ubuntu 18.04.