2043993 - discord not working after refresh

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect, P3)

Description

[mix5003]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:153.0) Gecko/20100101 Firefox/153.0

Steps to reproduce:

1. go to some channel in discord
2. refresh

Actual results:

it loading forever

Expected results:

it should load discord correctly.

Video for my problem: https://youtu.be/ZmmMqSRYZRE
in video i show 2 think that can solve issue.

1. use dev tool then tick "disable cache" then refresh
2. set dom.script_loader.experimental.navigation_cache to false (for confirm mozregression bug)
   and another way but i can not show in video is close tab then re-open again

Mozregression

2026-06-01T16:11:06.309000: DEBUG : Found commit message:
Bug 2027803 - Enable stencil navigation cache on nightly. r=nbp

Differential Revision: https://phabricator.services.mozilla.com/D291097


2026-06-01T16:11:06.312000: DEBUG : Did not find a branch, checking all integration branches
2026-06-01T16:11:06.313000: INFO : The bisection is done.
2026-06-01T16:11:06.459000: INFO : Stopped

Nightly profiler: https://share.firefox.dev/4o0J0cE

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Gecko Profiler' component, but is not confident enough to move the bug to that component.

Comment 2

[Matthew Gaudet (he/him) [:mgaudet]]

Nicolas could you take a look?

Comment 3

[BugBot [:suhaib / :marco]]

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.

Comment 4

[Bryan Thrall [:bthrall]]

Applying the "after" patch from bug 1999884 comment 1 reliably fixes this issue on my workstation, but insight.min.js doesn't seem to be involved like it is in bug 2042605.

I've experimented with only delaying one script at a time, but haven't found the script that fixes the issue when it is delayed.

Unassigning myself because I'm going on PTO. :arai, can you take a look?

Comment 5

[Tooru Fujisawa [:arai]]

The issue seems to be caused by the discord's loader functionality, which reuses script elements across multiple loads, and also uses onload event handler.

Discord loads 600+ script files, and each of them adds an element to this.webpackChunkdiscord_app array.
In the working case, it has 665 elements, but in the broken case, it has only 604 elements,
which means the load stops at some point.

https://discord.com/assets/web.c15e47a2f6e8fddd.js

A.l = function (e, t, n, i) {
  if (u[e]) return void u[e].push(t);
  if (void 0 !== n) for (
    var r,
    s,
    a = document.getElementsByTagName('script'),
    o = 0;
    o < a.length;
    o++
  ) {
    var l = a[o];
    if (
      l.getAttribute('src') == e ||
      l.getAttribute('data-rspack') == 'discord_app:' + n
    ) {
      r = l;
      break
    }
  }
  r ||
  (
    s = !0,
    (r = document.createElement('script')).timeout = 120,
    A.nc &&
    r.setAttribute('nonce', A.nc),
    r.setAttribute('data-rspack', 'discord_app:' + n),
    r.src = e
  ),
  u[e] = [
    t
  ];
  var c = function (t, n) {
    r.onerror = r.onload = null,
    clearTimeout(d);
    var i = u[e];
    if (
      delete u[e],
      r.parentNode &&
      r.parentNode.removeChild(r),
      i &&
      i.forEach(function (e) {
        return e(n)
      }),
      t
    ) return t(n)
  },
  d = setTimeout(c.bind(null, void 0, {
    type: 'timeout',
    target: r
  }), 120000);
  r.onerror = c.bind(null, r.onerror),
  r.onload = c.bind(null, r.onload),
  s &&
  document.head.appendChild(r)
}

For me, applying a delay only to https://discord.com/assets/03f84c299966cd36.js solves the issue,
but this is a localization file specific to Japanese, so it will be different for each user.

Anyway, bug 2042605 and also this bug proves that synchronously processing the script can cause issues,
and this situation happens only for in-memory cache, which doesn't require any IPC or network communication.
Thus, it should be reasonable to introduce one tick delay before processing the script, so that nothing is processed synchronously
after inserting the script element.

Comment 6

[Tooru Fujisawa [:arai]]

Attachment: Bug 2043993 - Delay the cached script processing by one tick to avoid processing too early. r?bthrall!

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/0ae205d1de26
https://hg.mozilla.org/integration/autoland/rev/11e216481ceb
Delay the cached script processing by one tick to avoid processing too early. r=bthrall

Comment 8

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/11e216481ceb

Comment 9

[Tooru Fujisawa [:arai]]

Attachment: Bug 2043993 - Delay the cached script processing by one tick to avoid processing too early.

Original Revision: https://phabricator.services.mozilla.com/D306434

Comment 10

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/ca66520493f8
https://hg.mozilla.org/releases/mozilla-beta/rev/e0a8fb70962a