x86_64 Cygwin 1.7.29: possible bug to trace symlink (Win7)

[Robert Bu]

-----Original Message-----
From: Robert Bu
Sent: 2014/4/21 9:59 +0800
>> On Apr 16 17:47, Corinna Vinschen wrote:
>>    > > Below is what I get:
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>uname -a
>>    > > CYGWIN_NT-6.1 RS-I9E3U8R4 1.7.29(0.272/5/3) 2014-04-07 13:46 x86_64
>> Cygwin
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>echo $CYGWIN
>>    > > winsymlinks:nativestrict
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>echo test > test.txt
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>mkdir dest
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>cd dest
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink/dest]>ln -s ../test.txt test.txt
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink/dest]>cd ../
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>mkdir src
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>cd src
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink/src]>ln -s ../dest dest
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink/src]>cd ../
>>    > > RS-I9E3U8R4:[~/tmp/test_symlink]>cat src/dest/test.txt
>>    > > cat: src/dest/test.txt: No such file or directory
>>    >
>>    > I can reproduce it now.  I made a mistake when creating the symlinks
>>    > the first time, which is, I created them with tcsh.  Tcsh tends to
>>    > change relative paths using ".." components to absolute paths on the
>>    > command line.  Using plain relative paths, I now see what's going on.
>>    >
>>    > But it'sa tricky problem.  I don't know how to fix it yet.  I'll
>>    > have to think about it, so please be patient.
>>
>> This is a very interesting problem which (again) shows the downsides of
>> the Cygwin path handling, namely the evaluation of the path from right
>> to left, contrary to what POSIX demands.  We really have to rewrite this
>> code, but that's a lot of work for long and dark winter nights and days,
>> not something we can do out of the blue.
>>
>> Therefore, I created a workaround within the constraints of the current
>> code.  Please try the today's snapshot from http://cygwin.com/snapshots/,
>> it contains my workaround.
>>
> This snapshots works as expected.
>
>> Note that in the current configuration we're having a recursion problem.
>> If your path consists of more than 15 native symlinks, all of which have
>> a ".." path component in the symlink target path, the result will be a
>> "no such file or directory" again.  This is pretty unlikely in normal
>> life, but can be easily constructed, of course.
>>
>
> There are about 10 native symlinks in the repo created git directory. So
> this workaround works for me for now.
>
> Thank you very much.
>
> Regards
> Robert
>
> .
>
Hi,

I get this problem again in 1.7.30 (x86_64) on Win7.
I think the snapshot "cygwin1-20140418-x64.dll" already fixed this problem.

Best regards.
Robert Bu



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