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Date: Fri, 23 Nov 2012 16:32:58 +0400
From: Andrey Repin <anrdaemon AT freemail DOT ru>
Reply-To: Andrey Repin <cygwin AT cygwin DOT com>
Message-ID: <1429797465.20121123163258@mtu-net.ru>
To: Corinna Vinschen <cygwin AT cygwin DOT com>
Subject: Re: git fork failure on pull with a workaround (hopefully a clue for a fix)
In-Reply-To: <20121123114127.GO17347@calimero.vinschen.de>
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Greetings, Corinna Vinschen!

>> >>Is there a
>> >>way to debug this?
>> >
>> >The first step is to follow the problem reporting guidelines:
>> >
>> >   http://cygwin.com/problems.html
>> >
>> >Following them may reveal a conflicting cygwin.dll file or something
>> >similar in your full path which is interfering with some git subcommand
>> >loading properly.
>> 
>> Attached is the cygcheck.out.
>> 
>> >
>> >Given that a PATH of just /usr/bin works for you, try appending
>> >progressively more segments of your original path until the problem
>> >reproduces.  Once you find a PATH that reliably fails, remove the last
>> >added segment as a suspect and continue adding the remaining segments
>> >from the original PATH until you are left with a good PATH and a list of
>> >suspects.  Then go back to the PATH of /usr/bin and append each suspect
>> >individually and test again to see if the suspects are the problem alone.
>> >
>> 
>> I had done that in the past and found that it seemed to be a length
>> issue.  I could not find a specific thing that needed to be in the
>> PATH to make it break.  I just tried again, and here is what I
>> found:
>> 
>> This fails:  (length 372)
>> 
>> export PATH="/usr/bin:/cygdrive/c/Program Files (x86)/Microsoft
>> Visual Studio 9.0/Common7/IDE:/cygdrive/c/Program Files
>> (x86)/Microsoft Visual Studio 9.0/VC/BIN:/cygdrive/c/Program Files
>> (x86)/Microsoft Visual Studio
>> 9.0/Common7/Tools:/cygdrive/c/Windows/Microsoft.NET/Framework/v3.5:/cygdrive/c/Windows/Microsoft.NET/Framework/v2.0.50727:/usr/local/bin:/usr/bin:/some/bogus/path/that"
>> 
>> 
>> But this works:  (length 371)
>> 
>> export PATH="/usr/bin:/cygdrive/c/Program Files (x86)/Microsoft
>> Visual Studio 9.0/Common7/IDE:/cygdrive/c/Program Files
>> (x86)/Microsoft Visual Studio 9.0/VC/BIN:/cygdrive/c/Program Files
>> (x86)/Microsoft Visual Studio 9.0/Common7/Tools:/cygdrive/c/Windows/Microsoft.NET/Framework/v3.5:/cygdrive/c/Windows/Microsoft.NET/Framework/v2.0.50727:/usr/local/bin:/usr/bin:/some/bogus/path/tha"
>> 
>> 
>> However, it is not just length....
>> 
>> Because this one works:  (length 400)

> I *think* this is an issue between Windows and Cygwin for which there's
> no easy solution.  The memory layout created by Windows can move the
> main stack address in a child process depending on the size of the
> environment.

> I observed this myself, but didn't find a way to fix it.  Maybe it's
> related to the fact that Cygwin cleans out the Windows environment to a
> bare minimum when forking.  This obviously results in a changed env.

Would it be meaningful to instrument this cause for easier tracking?


--
WBR,
Andrey Repin (anrdaemon AT freemail DOT ru) 23.11.2012, <16:31>

Sorry for my terrible english...


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