425146 - Proxy PAC hangs on bad hostname

Status: RESOLVED DUPLICATE of bug 235853

(Core :: Networking, defect)

Description

[Thomas Rutter]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b5pre) Gecko/2008031905 Minefield/3.0b5pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b5pre) Gecko/2008031905 Minefield/3.0b5pre

When fetching any URL containing a bad hostname (for example, accidentally adding a dot), the browser interface completely freezes for a while.  This freeze seems to last up to 15 seconds, though the UI can go on stuttering for a while.

Example bad hostnames:

http://.google.com/
http://google..com/



Reproducible: Always

Steps to Reproduce:
1. Set up network access via auto-configured proxy script (proxy.pac)
2. Go to http://.google.com/
Actual Results:  
UI freeze, unable to click on anything, for a number of seconds.  Then, UI unfreezes and page starts loading.  It is a page from squid proxy "Invalid URL"

Expected Results:  
The error page from the proxy is shown immediately.
OR
Such a bad hostname should not be sent to the proxy at all.

I am accessing the internet through an auto-configured proxy script (proxy.pac).  I haven't been able to determine if the problem is this proxy configuration yet.  Normal sites load fine.

Hangs but if you avoid the temptation to kill the process it usually goes back to normal after a while.

Comment 1

[Christian :Biesinger (don't email me, ping me on IRC)]

the PAC file is the reason

Comment 2

[benc]

REOPEN:

Can you attach the pac file, please?

Comment 3

[Thomas Rutter]

Attachment: proxy.pac file

slightly modified proxy.pac file (for privacy)

The problem may be in the DNS resolution.  Maybe Firefox is/was blocking (appearing to freeze) when the DNS resolution was taking a long time.