1312271 - annotate/blame fails (timeout) with content encoding error

Status: ASSIGNED

(Developer Services :: Mercurial: hg.mozilla.org, defect)

Description

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

If I try to load
https://hg.mozilla.org/releases/mozilla-aurora/annotate/96ca0ecdcfa7b14cab40e8c7a0a4d97441652a79/browser/locales/en-US/chrome/browser/downloads/downloads.dtd#l in both Firefox release (49.0.2) or Nightly (52.0a1) on Windows 8.1, the page loads until line 50, the throbber continues to spin, and later the page shows this error:

Content Encoding Error

The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression.

    Please contact the website owners to inform them of this problem.

Comment 1

[Gregory Szorc [:gps]]

I'm able to reproduce this in production but not locally. This failure is giving me bad vibes and I suspect it could lead to something bad. So marking the bug as confidential until I manage to pinpoint the failure.

Comment 2

[Gregory Szorc [:gps]]

As best I can tell, this is a performance issue in upstream Mercurial. Things are getting wonky with the browser because the WSGI server sends a partial HTTP chunked-transfer response and then something else (likely Apache) sends an HTTP 500 after N seconds of no output from WSGI. I'm pretty sure it isn't aborting the partial HTTP response correctly, leading to the browser complaining.

Comment 3

[Gregory Szorc [:gps]]

Upstream issue filed at https://bz.mercurial-scm.org/show_bug.cgi?id=5414.

Comment 4

[Gregory Szorc [:gps]]

I've submitted a patch upstream that should restore sanity: https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-November/090050.html

If accepted, that will get deployed to hg.mozilla.org ~Dec 1 when we deploy hg 4.0.