832614 - Extremely slow to open and close Error Console. And Extremely slow loading web page while Error Console is opened. Browser almost hang up.

Status: RESOLVED DUPLICATE of bug 831020

(Toolkit Graveyard :: Error Console, defect)

Description

[Alice0775 White]

Build Identifier:
http://hg.mozilla.org/mozilla-central/rev/b52c02f77cf5
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130118 Firefox/21.0 ID:20130118030915

Steps to reproduce:
1. Start Firefox with clean profile
2. Open any page which has CSS error/warning (Ex. https://www.google.co.jp/search?q=css3+3d&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-nightly )
   And Wait to completion to load the page
3. Open Error Console (Ctrl+Shift+J)
   --- observe the slow to open the Error Console
4. Reload the page
  --- observe slow loading the page
5. Close the Error Console
  --- observe the slow to close the Error Console


Actual results:
Extremely slow to open and close Error Console.
And Extremely slow loading web page while Error Console is opened.
Browser is almost hang up.

Expected results:
It should not do become so slow

Regression window(m-c)
Good:
http://hg.mozilla.org/mozilla-central/rev/1761f4a9081c
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130112 Firefox/21.0 ID:20130112030947
Bad:
http://hg.mozilla.org/mozilla-central/rev/d8599591d07c
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130112 Firefox/21.0 ID:20130112122707
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1761f4a9081c&tochange=d8599591d07c


Regression window(m-i)
Good:
http://hg.mozilla.org/integration/mozilla-inbound/rev/89b72b0cda19
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130111 Firefox/21.0 ID:20130111091111
Bad:
http://hg.mozilla.org/integration/mozilla-inbound/rev/028ce4b36b4e
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130111 Firefox/21.0 ID:20130111092811
Pushlog:
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=2bfc7fb79f78&tochange=ef384134776b

Triggered by:
028ce4b36b4e	Zack Weinberg — Bug 413958: report the text of the offending line in CSS error messages. r=dbaron

Comment 1

[Alice0775 White]

At least , a preference should be provided to disable the feature added by Bug 413958.

Comment 2

[Zack Weinberg (:zwol)]

I do not find the browser to be *extremely* slow under these conditions, but there definitely does seem to be a performance problem.  I think it is a consequence of minified CSS often being all on one line; the error console truncates very long lines after the first few hundred characters, but it *doesn't* truncate the ASCII-art pointer that it draws to the offending token, so those take a long time to create and render (see https://mxr.mozilla.org/mozilla-central/source/toolkit/components/console/content/consoleBindings.xml#193 )

I think this is formally a bug in the error console itself -- for very long lines, it should show a window of say 40 characters each way around the offending token -- but I'm willing to add a preference to disable error-text reporting to the CSS parser if we can't get the error console fixed.

Comment 3

[Zack Weinberg (:zwol)]

Actually, it looks like Jared Wein is already on this in bug 831020.