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Message-ID: <42C9B0DC.9010403@scytek.de>
Date: Mon, 04 Jul 2005 17:57:48 -0400
From: Volker Quetschke <quetschke AT scytek DOT de>
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To: cygwin AT cygwin DOT com
Subject: Re: Freeze in perl script after cygwin upgrade 1.5.17 -> 1.5.18
References: <42C96709 DOT 9030005 AT scytek DOT de> <20050704174424 DOT GA18735 AT trixie DOT casa DOT cgf DOT cx> <20050704181057 DOT GA19583 AT trixie DOT casa DOT cgf DOT cx>
In-Reply-To: <20050704181057.GA19583@trixie.casa.cgf.cx>
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>>>After upgrading cygwin yesterday I get the following reproducible hang
>>>in a perl script starting an external program.
>>>
>>>This is the perl script that works with the 1.5.17 cygwin dll and hangs
>>>with 1.5.18:
>>
>>Did you also see this with snapshots?
I didn't try. I will first try to condense the problem to a simpler testcase.
If that fails I can do a binary search backward.

> While waiting for the answer to the above rhetorical question, I thought
> I'd add an observation: Rather than go to a lot of effort running things
> and getting straces which may or may not illustrate the problem, it is
> ALWAYS a much better plan to reduce things to a simple test case which
> can be reproduced by people who may or may not use strace to debug the
> problem.
I know. I reduced the 10h build of OpenOffice.org to the 5 lines of perl
script that fails. I didn't expect an immediate solution for the problem,
but I attached the end of the strace anyway in the hope that it might
trigger an idea for someone.

> The division of labor should be like this:
> 
> The reporter more or less understands the code for which they are
> reporting problems so they should be able to reduce things, as much as
> possible, to a test case which reproduces the problem.  With a test case
> in hand, you can then hand off the problem to someone who understands
> cygwin and who will be able to use the simple test case to debug the
> problem.
Fair enough.

> Attempting to bypass the test case step and do the cygwin maintainer's
> "job" of generating strace output is not as likely to be a worthwhile
> endeavor as producing the test case itself.  You are not likely to jump
> start the debugging process by doing this.  Even if the strace output
> was useful, the debugger would have no real way of knowing if they fixed
> the problem without a test case.
Well, I could have waited reporting this problem until I have extracted
a 2 line testcase, but I wanted to post what I have so far.

> The theory here is that a bug reporter shouldn't need to spend any time
> trying to debug cygwin (via strace) unless they really are interested in
> learning about cygwin internals.  That means that the most profitable
> thing a bug reporter can do is create a test case.
Quote from the original mail:
 > * Attention! Stop reading if you're offended by unsolicited strace outputs. *

Stop wasting your precious time complaining about my useless strace. I didn't
waste much time producing it and it shows that perl is waiting for
something, not more.

Regards

      Volker

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