bug with .git file and aliases

bug with .git file and aliases

[Geoffrey Irving]

git 1.6.3.3 has a bug related to .git file support and aliases.
Specifically, if you make an alias for status and call it from a
subdirectory, git status chdirs into the true .git dir but then
chdir's back to the wrong place in order to run the lstats for status.
 The result is that git status thinks all files have disappeared.

Here's a self-contained test script:

    #!/bin/bash
    set -x

    # make a simple repository
    mkdir repo
    cd repo
    git init
    mkdir a
    echo content > a/b
    git add a/b
    git commit -m "a commit"

    # replace the gitdir with a gitfile
    mv .git ../repo.git
    echo gitdir: `pwd`.git > .git

    # normal git status works
    cd a
    git status

    # an alias for git status fails
    git config alias.st status
    git st

which produces output

top:tmp% ./bug
++ mkdir repo
++ cd repo
++ git init
Initialized empty Git repository in /Users/irving/tmp/tmp/repo/.git/
++ mkdir a
++ echo content
++ git add a/b
++ git commit -m 'a commit'
[master (root-commit) 6b07ec4] a commit
 1 files changed, 1 insertions(+), 0 deletions(-)
 create mode 100644 a/b
++ mv .git ../repo.git
+++ pwd
++ echo gitdir: /Users/irving/tmp/tmp/repo.git
++ cd a
++ git status
# On branch master
nothing to commit (working directory clean)
++ git config alias.st status
++ git st
# On branch master
# Changed but not updated:
#   (use "git add/rm <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	deleted:    a/b
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	b
no changes added to commit (use "git add" and/or "git commit -a")

.git file support also doesn't work on a repository with no commits
(which is why the test script makes a commit normally before switching
to a gitfile).  However, I care about this second problem much less,
and didn't notice it until I made the test script.

Finally, huge thanks to Lars for implementing this.  I'm storing git
working directories inside vesta, and symlink support is currently
disabled.  It's very pleasant to grep through the source and find that
someone already fixed exactly my problem. :)

Geoffrey

Re: bug with .git file and aliases

[Santi Béjar]

2009/7/20 Geoffrey Irving <irving@naml.us>:
> git 1.6.3.3 has a bug related to .git file support and aliases.
> Specifically, if you make an alias for status and call it from a
> subdirectory, git status chdirs into the true .git dir but then
> chdir's back to the wrong place in order to run the lstats for status.
>  The result is that git status thinks all files have disappeared.
>
> Here's a self-contained test script:
>
>    #!/bin/bash
>    set -x
>
>    # make a simple repository
>    mkdir repo
>    cd repo
>    git init
>    mkdir a
>    echo content > a/b
>    git add a/b
>    git commit -m "a commit"
>
>    # replace the gitdir with a gitfile
>    mv .git ../repo.git
>    echo gitdir: `pwd`.git > .git
>
>    # normal git status works
>    cd a
>    git status
>
>    # an alias for git status fails
>    git config alias.st status
>    git st

I suspect that the $GIR_DIR and .git file works equally in this
aspect, so you should specify where is the workdir in .git/config with
respect the repository:

git config core.workdir `pwd`

HTH,
Santi

Re: bug with .git file and aliases

[Geoffrey Irving]

On Mon, Jul 20, 2009 at 10:04 AM, Santi Béjar<santi@agolina.net> wrote:
> I suspect that the $GIR_DIR and .git file works equally in this
> aspect, so you should specify where is the workdir in .git/config with
> respect the repository:
>
> git config core.workdir `pwd`

Nope, that has no effect.

By the way, I can work around this problem by using

    git config alias.st "!git status"

but unfortunately that has slightly different behavior (it ignores pwd).

Geoffrey

Re: bug with .git file and aliases

[Santi Béjar]

2009/7/20 Geoffrey Irving <irving@naml.us>:
> On Mon, Jul 20, 2009 at 10:04 AM, Santi Béjar<santi@agolina.net> wrote:
>> I suspect that the $GIR_DIR and .git file works equally in this
>> aspect, so you should specify where is the workdir in .git/config with
>> respect the repository:
>>
>> git config core.workdir `pwd`
>
> Nope, that has no effect.

Here it has the desired effect. From where did you run the above
command? What is the output of:

git config core.workdir

?

It should output the path of the repo, not of the "a" subdirectory.

HTH,
Santi

Re: bug with .git file and aliases

[Jeff King]

On Mon, Jul 20, 2009 at 09:54:12AM -0400, Geoffrey Irving wrote:

> git 1.6.3.3 has a bug related to .git file support and aliases.
> Specifically, if you make an alias for status and call it from a
> subdirectory, git status chdirs into the true .git dir but then
> chdir's back to the wrong place in order to run the lstats for status.
>  The result is that git status thinks all files have disappeared.

Yeah, this is a known problem. The problem is that the 'git' wrapper
sets up the environment only partially when running aliases, and then
the resulting command ends up confused about where the worktree is. I
really don't remember the specifics, but you can probably find some
discussion in the list archives.  Fixing it, IIRC, required some
refactoring of the setup code (which I had hoped to get to at some
point, but I am way behind on my git todo list).

Hmm. Poking around a bit, this seems related, but I don't know why I
never followed up:

  http://article.gmane.org/gmane.comp.version-control.git/72792

-Peff

Re: bug with .git file and aliases

[Geoffrey Irving]

On Mon, Jul 20, 2009 at 11:18 AM, Santi Béjar<santi@agolina.net> wrote:
> 2009/7/20 Geoffrey Irving <irving@naml.us>:
>> On Mon, Jul 20, 2009 at 10:04 AM, Santi Béjar<santi@agolina.net> wrote:
>>> I suspect that the $GIR_DIR and .git file works equally in this
>>> aspect, so you should specify where is the workdir in .git/config with
>>> respect the repository:
>>>
>>> git config core.workdir `pwd`
>>
>> Nope, that has no effect.
>
> Here it has the desired effect. From where did you run the above
> command? What is the output of:
>
> git config core.workdir

top:a% git config core.workdir
/Users/irving/tmp/tmp/repo
top:a% git st
# On branch master
# Changed but not updated:
#   (use "git add/rm <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	deleted:    a/b
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	b

It doesn't matter, though, since setting workdir should not be necessary.

Geoffrey

Re: bug with .git file and aliases

[Geoffrey Irving]

[-- Attachment #1: Type: text/plain, Size: 1121 bytes --]

On Mon, Jul 20, 2009 at 11:21 AM, Jeff King<peff@peff.net> wrote:
> On Mon, Jul 20, 2009 at 09:54:12AM -0400, Geoffrey Irving wrote:
>
>> git 1.6.3.3 has a bug related to .git file support and aliases.
>> Specifically, if you make an alias for status and call it from a
>> subdirectory, git status chdirs into the true .git dir but then
>> chdir's back to the wrong place in order to run the lstats for status.
>>  The result is that git status thinks all files have disappeared.
>
> Yeah, this is a known problem. The problem is that the 'git' wrapper
> sets up the environment only partially when running aliases, and then
> the resulting command ends up confused about where the worktree is. I
> really don't remember the specifics, but you can probably find some
> discussion in the list archives.  Fixing it, IIRC, required some
> refactoring of the setup code (which I had hoped to get to at some
> point, but I am way behind on my git todo list).

The attached patch fixes the bug for me.  I'll leave it to others to
determine whether this is a good way to fix the problem.

Thanks,
Geoffrey

[-- Attachment #2: 0001-setup.c-fix-work-tree-setup-for-.git-files-and-alias.patch --]
[-- Type: text/x-patch, Size: 1797 bytes --]

From ec47aa09e5bc8d9a8c07cca9f8ef17a9898819c1 Mon Sep 17 00:00:00 2001
From: Geoffrey Irving <irving@naml.us>
Date: Mon, 10 Aug 2009 15:59:21 -0400
Subject: [PATCH] setup.c: fix work tree setup for .git-files and aliases

When .git-files and aliases are used together, the setup machinery
gets confused and ends up with the wrong work_tree.  Specifically,
git_work_tree_cfg is set to the correct value first, but set_work_tree
resets git_work_tree_cfg to the current directory, which (at least in
this case) is incorrect.

set_work_tree now detects this case by checking to see if
git_work_tree_cfg is already set.  If so, it leaves git_work_tree_cfg
unchanged and instead uses the current directory to compute and return
the correct prefix (where we are relative to the work tree).

Signed-off-by: Geoffrey Irving <irving@naml.us>
---
 setup.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/setup.c b/setup.c
index e3781b6..97f7eb1 100644
--- a/setup.c
+++ b/setup.c
@@ -198,13 +198,24 @@ int is_inside_work_tree(void)
 static const char *set_work_tree(const char *dir)
 {
 	char buffer[PATH_MAX + 1];
+	size_t offset;
 
 	if (!getcwd(buffer, sizeof(buffer)))
 		die ("Could not get the current working directory");
-	git_work_tree_cfg = xstrdup(buffer);
 	inside_work_tree = 1;
 
-	return NULL;
+	if (!git_work_tree_cfg) {
+		git_work_tree_cfg = xstrdup(buffer);
+		return NULL;
+	} else {
+		offset = strlen(git_work_tree_cfg);
+		if (memcmp(git_work_tree_cfg, buffer, offset)
+			|| (buffer[offset] && buffer[offset] != '/'))
+			die ("fatal: not inside work tree (should not happen)");
+		if (!buffer[offset] || !buffer[offset+1])
+			return NULL;
+		return xstrdup(strcat(buffer + offset + 1, "/"));
+	}
 }
 
 void setup_work_tree(void)
-- 
1.6.3.3

Re: bug with .git file and aliases

[Johannes Schindelin]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1933 bytes --]

Hi,

On Mon, 10 Aug 2009, Geoffrey Irving wrote:

> On Mon, Jul 20, 2009 at 11:21 AM, Jeff King<peff@peff.net> wrote:
> > On Mon, Jul 20, 2009 at 09:54:12AM -0400, Geoffrey Irving wrote:
> >
> >> git 1.6.3.3 has a bug related to .git file support and aliases.
> >> Specifically, if you make an alias for status and call it from a
> >> subdirectory, git status chdirs into the true .git dir but then
> >> chdir's back to the wrong place in order to run the lstats for status.
> >>  The result is that git status thinks all files have disappeared.
> >
> > Yeah, this is a known problem. The problem is that the 'git' wrapper
> > sets up the environment only partially when running aliases, and then
> > the resulting command ends up confused about where the worktree is. I
> > really don't remember the specifics, but you can probably find some
> > discussion in the list archives.  Fixing it, IIRC, required some
> > refactoring of the setup code (which I had hoped to get to at some
> > point, but I am way behind on my git todo list).
> 
> The attached patch fixes the bug for me.  I'll leave it to others to
> determine whether this is a good way to fix the problem.

Note that you made it particularly hard to comment on your patch by not 
granting us the wish stated in Documentation/SubmittingPatches, namely to 
inline your patch.

I'll just forego inlining it myself, as I am way past my bed-time and 
cannot be bothered.

However, I think that it is necessary to comment on your patch.

There is a few style issues, such as declaring offset outside of the 
block that is the only user, and there is the issue that you go out of 
your way to append a slash if you're resetting the work tree, but not when 
not resetting it.

But the bigger issue is that you now broke overriding the work tree via 
the command line.

The proper fix, of course, is to avoid calling the function with the wrong 
path to begin with.

Ciao,
Dscho

Re: bug with .git file and aliases

[Geoffrey Irving]

On Mon, Aug 10, 2009 at 7:05 PM, Johannes
Schindelin<Johannes.Schindelin@gmx.de> wrote:
> Hi,
>
> On Mon, 10 Aug 2009, Geoffrey Irving wrote:
>
>> On Mon, Jul 20, 2009 at 11:21 AM, Jeff King<peff@peff.net> wrote:
>> > On Mon, Jul 20, 2009 at 09:54:12AM -0400, Geoffrey Irving wrote:
>> >
>> >> git 1.6.3.3 has a bug related to .git file support and aliases.
>> >> Specifically, if you make an alias for status and call it from a
>> >> subdirectory, git status chdirs into the true .git dir but then
>> >> chdir's back to the wrong place in order to run the lstats for status.
>> >>  The result is that git status thinks all files have disappeared.
>> >
>> > Yeah, this is a known problem. The problem is that the 'git' wrapper
>> > sets up the environment only partially when running aliases, and then
>> > the resulting command ends up confused about where the worktree is. I
>> > really don't remember the specifics, but you can probably find some
>> > discussion in the list archives.  Fixing it, IIRC, required some
>> > refactoring of the setup code (which I had hoped to get to at some
>> > point, but I am way behind on my git todo list).
>>
>> The attached patch fixes the bug for me.  I'll leave it to others to
>> determine whether this is a good way to fix the problem.
>
> Note that you made it particularly hard to comment on your patch by not
> granting us the wish stated in Documentation/SubmittingPatches, namely to
> inline your patch.
>
> I'll just forego inlining it myself, as I am way past my bed-time and
> cannot be bothered.

Oops.  Here's the inlined patch with offset fixed, for others:

From ec47aa09e5bc8d9a8c07cca9f8ef17a9898819c1 Mon Sep 17 00:00:00 2001
From: Geoffrey Irving <irving@naml.us>
Date: Mon, 10 Aug 2009 15:59:21 -0400
Subject: [PATCH] setup.c: fix work tree setup for .git-files and aliases

When .git-files and aliases are used together, the setup machinery
gets confused and ends up with the wrong work_tree.  Specifically,
git_work_tree_cfg is set to the correct value first, but set_work_tree
resets git_work_tree_cfg to the current directory, which (at least in
this case) is incorrect.

set_work_tree now detects this case by checking to see if
git_work_tree_cfg is already set.  If so, it leaves git_work_tree_cfg
unchanged and instead uses the current directory to compute and return
the correct prefix (where we are relative to the work tree).

Signed-off-by: Geoffrey Irving <irving@naml.us>
---
 setup.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/setup.c b/setup.c
index e3781b6..97f7eb1 100644
--- a/setup.c
+++ b/setup.c
@@ -198,13 +198,24 @@ int is_inside_work_tree(void)
 static const char *set_work_tree(const char *dir)
 {
 	char buffer[PATH_MAX + 1];

 	if (!getcwd(buffer, sizeof(buffer)))
 		die ("Could not get the current working directory");
-	git_work_tree_cfg = xstrdup(buffer);
 	inside_work_tree = 1;

-	return NULL;
+	if (!git_work_tree_cfg) {
+		git_work_tree_cfg = xstrdup(buffer);
+		return NULL;
+	} else {
+		size_t offset = strlen(git_work_tree_cfg);
+		if (memcmp(git_work_tree_cfg, buffer, offset)
+			|| (buffer[offset] && buffer[offset] != '/'))
+			die ("fatal: not inside work tree (should not happen)");
+		if (!buffer[offset] || !buffer[offset+1])
+			return NULL;
+		return xstrdup(strcat(buffer + offset + 1, "/"));
+	}
 }

 void setup_work_tree(void)
-- 
1.6.3.3

> However, I think that it is necessary to comment on your patch.
>
> There is a few style issues, such as declaring offset outside of the
> block that is the only user, and there is the issue that you go out of
> your way to append a slash if you're resetting the work tree, but not when
> not resetting it.
>
> But the bigger issue is that you now broke overriding the work tree via
> the command line.
>
> The proper fix, of course, is to avoid calling the function with the wrong
> path to begin with.

I'm happy that the correct fix is obvious, and apologize for missing it.

Geoffrey

Re: bug with .git file and aliases

[Johannes Schindelin]

Hi,

On Mon, 10 Aug 2009, Geoffrey Irving wrote:

> On Mon, Aug 10, 2009 at 7:05 PM, Johannes
> Schindelin<Johannes.Schindelin@gmx.de> wrote:
>
> > The proper fix, of course, is to avoid calling the function with the 
> > wrong path to begin with.
> 
> I'm happy that the correct fix is obvious, and apologize for missing it.

No, no, I said that it is obvious what should be fixed (you do not want 
to break perfectly valid workflows such as having a worktree set in the 
config, but overriding it via git's --work-tree option).  The fix is not 
obvious, unfortunately.

See also http://thread.gmane.org/gmane.comp.version-control.git/102269 for 
some discussion on the same topic.

Ciao,
Dscho

Re: bug with .git file and aliases

[Michael J Gruber]

Jeff King venit, vidit, dixit 20.07.2009 17:21:
> On Mon, Jul 20, 2009 at 09:54:12AM -0400, Geoffrey Irving wrote:
> 
>> git 1.6.3.3 has a bug related to .git file support and aliases.
>> Specifically, if you make an alias for status and call it from a
>> subdirectory, git status chdirs into the true .git dir but then
>> chdir's back to the wrong place in order to run the lstats for status.
>>  The result is that git status thinks all files have disappeared.
> 
> Yeah, this is a known problem. The problem is that the 'git' wrapper
> sets up the environment only partially when running aliases, and then
> the resulting command ends up confused about where the worktree is. I
> really don't remember the specifics, but you can probably find some
> discussion in the list archives.  Fixing it, IIRC, required some
> refactoring of the setup code (which I had hoped to get to at some
> point, but I am way behind on my git todo list).
> 
> Hmm. Poking around a bit, this seems related, but I don't know why I
> never followed up:
> 
>   http://article.gmane.org/gmane.comp.version-control.git/72792
> 
> -Peff

...because it was up to the brave git-on-win folks to decide whether
setenv() on win would be rewritten to not use putenv() when the value is
"". J&J, has anything happened on the front or is it likely to? (I'm
sorry I can't offer help, only moral support...)

Jeff's patch from Feb. 08 still applies more or less cleanly (with
obvious adjustments) and makes the relevant tests pass (on Linux).

Michael

Re: bug with .git file and aliases

[Johannes Sixt]

Michael J Gruber schrieb:
> ...because it was up to the brave git-on-win folks to decide whether
> setenv() on win would be rewritten to not use putenv() when the value is
> "". J&J, has anything happened on the front or is it likely to? (I'm
> sorry I can't offer help, only moral support...)

Nothing has changed since. Nothing is likely to happen until there is a
need to touch compat/setenv.c, like, for example, a test in the test suite
that fails only on Windows...

-- Hannes

Re: bug with .git file and aliases

[Michael J Gruber]

Johannes Sixt venit, vidit, dixit 11.08.2009 12:26:
> Michael J Gruber schrieb:
>> ...because it was up to the brave git-on-win folks to decide whether
>> setenv() on win would be rewritten to not use putenv() when the value is
>> "". J&J, has anything happened on the front or is it likely to? (I'm
>> sorry I can't offer help, only moral support...)
> 
> Nothing has changed since. Nothing is likely to happen until there is a
> need to touch compat/setenv.c, like, for example, a test in the test suite
> that fails only on Windows...

...well, that can be taken care of quickly. Go, Jeff, go :)

Michael