ZSH segmentation fault while completing "git mv dir/"

ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Hi,

Since the recent update to bash completion, I often get a segmentation
fault from ZSH. This is most likely a bug in ZSH, but it would be cool
to avoid triggering it from Git.

Steps to reproduce:

moy@anie:/tmp$$ git init zsh
Initialized empty Git repository in /tmp/zsh/.git/
moy@anie:/tmp$$ cd zsh/
moy@anie:/tmp/zsh$$ mkdir foo
moy@anie:/tmp/zsh$$ touch foo/bar.txt
moy@anie:/tmp/zsh$$ git mv foo/zsh: segmentation fault  zsh
moy@anie:~$ zsh --version
zsh 4.3.10 (i686-pc-linux-gnu)

(this is ZSH packaged with Debian stable)

Any ZSH guru to look into it?

Thanks,

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: ZSH segmentation fault while completing "git mv dir/"

[Manlio Perillo]

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Hash: SHA1

Il 11/03/2013 13:30, Matthieu Moy ha scritto:
> Hi,
> 
> Since the recent update to bash completion, I often get a segmentation
> fault from ZSH. This is most likely a bug in ZSH, but it would be cool
> to avoid triggering it from Git.
> 
> [...]
> moy@anie:~$ zsh --version
> zsh 4.3.10 (i686-pc-linux-gnu)
> 
> (this is ZSH packaged with Debian stable)
> 

I have the same system, but I can't reproduce the problem.
What is the content of your .zshrc file?


Regards  Manlio Perillo
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Re: ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Manlio Perillo <manlio.perillo@gmail.com> writes:

> I have the same system, but I can't reproduce the problem.
> What is the content of your .zshrc file?

I could reproduce with ~/.zshrc containing just:

----------------------------------------------
fpath=(${HOME}/usr/etc/zsh ${fpath})

autoload -Uz compinit
compinit

eval "`dircolors`"
zstyle ':completion:*' list-colors ${(s.:.)LS_COLORS}
----------------------------------------------

${HOME}/usr/etc/zsh contains two links _git and git-completion.bash
pointing to Git's completion scripts in contrib/.

Removing any line aboves removes the segmentation fault.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: ZSH segmentation fault while completing "git mv dir/"

[Manlio Perillo]

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Il 11/03/2013 16:37, Matthieu Moy ha scritto:
> [...]
> I could reproduce with ~/.zshrc containing just:
> 
> ----------------------------------------------
> fpath=(${HOME}/usr/etc/zsh ${fpath})
> 
> autoload -Uz compinit
> compinit
> 
> eval "`dircolors`"
> zstyle ':completion:*' list-colors ${(s.:.)LS_COLORS}
> ----------------------------------------------
> 
> ${HOME}/usr/etc/zsh contains two links _git and git-completion.bash
> pointing to Git's completion scripts in contrib/.
> 

Using this configuration I still can't reproduce the problem, using
git v1.8.2-rc3-8-g0c91a6f.

But I'm not a zsh expert.



Regards   Manlio Perillo

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Re: ZSH segmentation fault while completing "git mv dir/"

[Jeff Epler]

If it's dependent on eval "`dircolors`", it suggests it might be
dependent on the size of the environment.  Maybe try with FOO=`perl -e
'print "x"x1000'` for various values of 1000...

Jeff

Re: ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Jeff Epler <jepler@unpythonic.net> writes:

> If it's dependent on eval "`dircolors`", it suggests it might be
> dependent on the size of the environment.  Maybe try with FOO=`perl -e
> 'print "x"x1000'` for various values of 1000...

It's not this, but I could reduce the problem to a slightly simpler
.zshrc:

-----------------------------------------------------------------
fpath=(${HOME}/usr/etc/zsh ${fpath})

autoload -Uz compinit
compinit

zstyle ':completion:*' list-colors 'rs=0' 'di=01;34' 'ln=01;36' \
 'mh=00' 'pi=40;33' 'so=01;35' 'do=01;35' 'bd=40;33;01' 'cd=40;33;01' \
 'or=40;31;01' 'su=37;41' 'sg=30;43' 'ca=30;41' 'tw=30;42' 'ow=34;42' \
 'st=37;44' 'ex=01;32' '*.tar=01;31' '*.tgz=01;31' '*.arj=01;31'  \
 '*.taz=01;31' '*.lzh=01;31' '*.lzma=01;31' '*.tlz=01;31' '*.txz=01;31' \
 '*.zip=01;31' '*.z=01;31' '*.Z=01;31' '*.dz=01;31' '*.gz=01;31'  \
 '*.lz=01;31' '*.xz=01;31' '*.bz2=01;31' '*.bz=01;31' '*.tbz=01;31'  \
 '*.tbz2=01;31' '*.tz=01;31' '*.deb=01;31' '*.rpm=01;31' '*.jar=01;31' \
 '*.rar=01;31' '*.ace=01;31' '*.pgm=01;35' '*.ppm=01;35'  \
 '*.tga=01;35' '*.xbm=01;35' '*.zoo=01;31' '*.cpio=01;31' '*.7z=01;31' \
 '*.rz=01;31' '*.jpg=01;35' '*.jpeg=01;35' '*.gif=01;35' \
 '*.bmp=01;35' '*.pbm=01;35'
-----------------------------------------------------------------

The problem disapears if I remove one of the arguments after list-colors
(I didn't try with each of them, but picking 5 of them randomly and
removing it worked), so it seems to be a matter of number of arguments.

On git-completion.bash's side, it's really strange. If I comment out the
"case" statement in _git_mv like this, the problem disapears:


_git_mv ()
{
	# case "$cur" in
	# --*)
	# 	__gitcomp "--dry-run"
	# 	return
	# 	;;
	# esac

	if [ $(__git_count_arguments "mv") -gt 0 ]; then
		# We need to show both cached and untracked files (including
		# empty directories) since this may not be the last argument.
		__git_complete_index_file "--cached --others --directory"
	else
		__git_complete_index_file "--cached"
	fi
}

If I add a simple 'echo "$cur" >&2' instead of the case, the problem
reappears. Somehow, the fact that I'm accessing $cur seems to create the
segfault. Actually, the minimalistic _git_mv reproducing the problem is:

_git_mv ()
{
	echo "$cur"
	[ $(__git_count_arguments "mv") = 1 ]
	__git_complete_index_file "--cached --others --directory"
}

gdb doesn't say much interesting since my ZSH isn't compile with debug:

(gdb) r
Starting program: /usr/bin/zsh 
anie$ cd /tmp/git
anie$ git mv subdir/
Program received signal SIGSEGV, Segmentation fault.
__strlen_sse2 () at ../sysdeps/i386/i686/multiarch/strlen.S:87
87	../sysdeps/i386/i686/multiarch/strlen.S: No such file or directory.
	in ../sysdeps/i386/i686/multiarch/strlen.S
Current language:  auto
The current source language is "auto; currently asm".
(gdb) where
#0  __strlen_sse2 () at ../sysdeps/i386/i686/multiarch/strlen.S:87
#1  0x080ae31d in ztrdup ()
#2  0xb7b9d287 in permmatches () from /usr/lib/zsh/4.3.10/zsh/complete.so
#3  0xb7b9a22e in ?? () from /usr/lib/zsh/4.3.10/zsh/complete.so
#4  0x08098f33 in getstrvalue ()
#5  0x08099e9d in ?? ()
#6  0x0809acd7 in getindex ()
#7  0x0809b3d9 in fetchvalue ()
#8  0x080b0f84 in ?? ()
#9  0x080b49a7 in prefork ()
#10 0x08066cb9 in ?? ()
#11 0x08067151 in ?? ()
#12 0x0806cfc0 in execlist ()
#13 0x0808984c in execif ()
#14 0x080670c6 in ?? ()
#15 0x0806cfc0 in execlist ()
#16 0x0806d69a in execode ()
#17 0x0806d785 in runshfunc ()
#18 0xb7b99a7a in ?? () from /usr/lib/zsh/4.3.10/zsh/complete.so
#19 0x0806d724 in runshfunc ()
#20 0x0806db92 in doshfunc ()
#21 0xb7ba3363 in ?? () from /usr/lib/zsh/4.3.10/zsh/complete.so
#22 0xb7ba44dc in do_completion () from /usr/lib/zsh/4.3.10/zsh/complete.so
#23 0xb7bdaf47 in ?? () from /usr/lib/zsh/4.3.10/zsh/zle.so
#24 0xb7bd5b40 in completecall () from /usr/lib/zsh/4.3.10/zsh/zle.so
#25 0xb7bc6f6e in execzlefunc () from /usr/lib/zsh/4.3.10/zsh/zle.so
#26 0xb7bc72a2 in zlecore () from /usr/lib/zsh/4.3.10/zsh/zle.so
#27 0xb7bc78d5 in zleread () from /usr/lib/zsh/4.3.10/zsh/zle.so
#28 0xb7bc96ff in ?? () from /usr/lib/zsh/4.3.10/zsh/zle.so
#29 0x0807d462 in zleentry ()
#30 0x08080a31 in ingetc ()
#31 0x0807b03c in ?? ()
#32 0x08087fb6 in zshlex ()
#33 0x080a3b4a in parse_event ()
#34 0x0807f2f1 in loop ()
#35 0x080800c6 in zsh_main ()
#36 0x08054cbb in main ()

I can't reproduce the problem with the exact same config and a freshly
compiled ZSH (so it's no use reporting the issue to the ZSH developers).

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: ZSH segmentation fault while completing "git mv dir/"

[Felipe Contreras]

On Tue, Mar 12, 2013 at 1:53 AM, Matthieu Moy
<Matthieu.Moy@grenoble-inp.fr> wrote:

> If I add a simple 'echo "$cur" >&2' instead of the case, the problem
> reappears. Somehow, the fact that I'm accessing $cur seems to create the
> segfault. Actually, the minimalistic _git_mv reproducing the problem is:
>
> _git_mv ()
> {
>         echo "$cur"
>         [ $(__git_count_arguments "mv") = 1 ]
>         __git_complete_index_file "--cached --others --directory"
> }

I managed to reproduce the issue, and to me, this is enough:

_git_mv ()
{
__gitcomp_file 'bar.txt' 'foo/'
}

And this is a workaround:

--- a/contrib/completion/git-completion.zsh
+++ b/contrib/completion/git-completion.zsh
@@ -66,7 +66,7 @@ __gitcomp_file ()

        local IFS=$'\n'
        compset -P '*[=:]'
-       compadd -Q -p "${2-}" -f -- ${=1} && _ret=0
+       compadd -Q -p "${2-}" -- ${=1} && _ret=0
 }

 _git ()

Cheers.

--
Felipe Contreras

Re: ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Felipe Contreras <felipe.contreras@gmail.com> writes:

> And this is a workaround:
>
> --- a/contrib/completion/git-completion.zsh
> +++ b/contrib/completion/git-completion.zsh
> @@ -66,7 +66,7 @@ __gitcomp_file ()
>
>         local IFS=$'\n'
>         compset -P '*[=:]'
> -       compadd -Q -p "${2-}" -f -- ${=1} && _ret=0
> +       compadd -Q -p "${2-}" -- ${=1} && _ret=0
>  }

OK, not something we want to apply to git.git, but this means a
workaround for users is to create a _git file with this content instead
instead of copying/symlinking git-completion.zsh as _git (replace
$GIT_ROOT_PATH with the appropriate value):

. $GIT_ROOT_PATH/contrib/completion/git-completion.zsh

# Work around ZSH bug on zsh 4.3.10-dev-1-cvs0720, which segfaults
# when completing "git mv subdir/<tab>" by redefining __gitcomp_file
__gitcomp_file ()
{
	emulate -L zsh

	local IFS=$'\n'
	compset -P '*[=:]'
	# The original had a -f here to indicate file completion.
	compadd -Q -p "${2-}" -- ${=1} && _ret=0
}

(Hope this helps in case someone has the same problem and finds this
thread ...)

Thanks,

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: ZSH segmentation fault while completing "git mv dir/"

[Junio C Hamano]

Matthieu Moy <Matthieu.Moy@grenoble-inp.fr> writes:

> Felipe Contreras <felipe.contreras@gmail.com> writes:
>
>> And this is a workaround:
>>
>> --- a/contrib/completion/git-completion.zsh
>> +++ b/contrib/completion/git-completion.zsh
>> @@ -66,7 +66,7 @@ __gitcomp_file ()
>>
>>         local IFS=$'\n'
>>         compset -P '*[=:]'
>> -       compadd -Q -p "${2-}" -f -- ${=1} && _ret=0
>> +       compadd -Q -p "${2-}" -- ${=1} && _ret=0
>>  }
>
> OK, not something we want to apply to git.git, but this means a
> workaround for users is to ...

Would it help users more to have that as part of the instruction at
the beginning of contrib/completion/git-completion.zsh where it
already says "here is how you use it via fpath", than leaving it
here in the list archive?

> (Hope this helps in case someone has the same problem and finds this
> thread ...)

Re: ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Junio C Hamano <gitster@pobox.com> writes:

> Would it help users more to have that as part of the instruction at
> the beginning of contrib/completion/git-completion.zsh where it
> already says "here is how you use it via fpath", than leaving it
> here in the list archive?

Juging from the answers I got, I do not think many people are hit by the
bug, and the problem will anyway disappear as people update their ZSH,
so I'm not sure it's worth the trouble.

This thread is already #1 on google with "git zsh segmentation fault" so
it's not terribly difficult to find.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/

Re: ZSH segmentation fault while completing "git mv dir/"

[Manlio Perillo]

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Hash: SHA1

Il 02/04/2013 16:32, Matthieu Moy ha scritto:
> Felipe Contreras <felipe.contreras@gmail.com> writes:
> 
>> And this is a workaround:
>>
>> --- a/contrib/completion/git-completion.zsh
>> +++ b/contrib/completion/git-completion.zsh
>> @@ -66,7 +66,7 @@ __gitcomp_file ()
>>
>>         local IFS=$'\n'
>>         compset -P '*[=:]'
>> -       compadd -Q -p "${2-}" -f -- ${=1} && _ret=0
>> +       compadd -Q -p "${2-}" -- ${=1} && _ret=0
>>  }
> 
> OK, not something we want to apply to git.git, but this means a
> workaround for users is to create a _git file with this content instead
> instead of copying/symlinking git-completion.zsh as _git (replace
> $GIT_ROOT_PATH with the appropriate value)

By the way: have you filled a bug report to Debian?


Regards  Manlio
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Re: ZSH segmentation fault while completing "git mv dir/"

[Matthieu Moy]

Manlio Perillo <manlio.perillo@gmail.com> writes:

> By the way: have you filled a bug report to Debian?

No, but this is a bug touching very few users, in Debian stable which is
reaching its end of life. I do not think the Debian folks would be
interested in fixing this non-security, non-critical bug now.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/