Re: [PATCH v1] worktree: set worktree environment in post-checkout hook

[Eric Sunshine]

On Fri, Feb 9, 2018 at 8:01 PM,   wrote:
> In ade546be47 (worktree: invoke post-checkout hook (unless
> --no-checkout), 2017-12-07) we taught Git to run the post-checkout hook
> in worktrees. Unfortunately, the environment of the hook was not made
> aware of the worktree. Consequently, a 'git rev-parse --show-toplevel'
> call in the post-checkout hook would return a wrong result.
>
> Fix this by setting the 'GIT_WORK_TREE' environment variable to make
> Git calls within the post-checkout hook aware of the worktree.
>
> Signed-off-by: Lars Schneider 
> ---
> I think this is a bug in Git 2.16. We noticed it because it caused a
> problem in Git LFS [1]. The modified test case fails with Git 2.16 and
> succeeds with this patch.

Thanks for reporting and diagnosing the problem.

I have some concerns about this patch's fix of setting GIT_WORK_TREE
unconditionally. In particular, such unconditional setting of
GIT_WORK_TREE might cause unforeseen problems. Although the
circumstances may not be quite the same, but the tale told by
86d26f240f (setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE
when .., 2015-12-20) makes me cautious.

More significantly, though, setting GIT_WORK_TREE seems too
specialized a solution. While it may "fix" Git commands invoked by the
hook, it does nothing for other commands ('cp', 'mv', etc.) which the
hook may employ.

As a review comment, I was going to suggest that you chdir() to the
new worktree directory instead of messing with GIT_WORK_TREE, but when
I tested it myself before making the suggestion, I discovered that the
issue is a bit more involved. The result is that I ended up posting a
patch series[1] to replace this one, with what I believe is a more
correct fix.

[1]: 
https://public-inbox.org/git/20180212031526.40039-1-sunsh...@sunshineco.com/

Re: [PATCH v1] worktree: set worktree environment in post-checkout hook

[Lars Schneider]

> On 10 Feb 2018, at 02:01, lars.schnei...@autodesk.com wrote:
> 
> From: Lars Schneider 
> 
> In ade546be47 (worktree: invoke post-checkout hook (unless
> --no-checkout), 2017-12-07) we taught Git to run the post-checkout hook
> in worktrees. Unfortunately, the environment of the hook was not made
> aware of the worktree. Consequently, a 'git rev-parse --show-toplevel'
> call in the post-checkout hook would return a wrong result.
> 
> Fix this by setting the 'GIT_WORK_TREE' environment variable to make
> Git calls within the post-checkout hook aware of the worktree.
> 
> Signed-off-by: Lars Schneider 
> ---
> 
> Hi,
> 
> I think this is a bug in Git 2.16. We noticed it because it caused a
> problem in Git LFS [1]. The modified test case fails with Git 2.16 and
> succeeds with this patch.
> 
> Cheers,
> Lars
> 
> 
> [1] https://github.com/git-lfs/git-lfs/issues/2848
> 
> 
> Notes:
>Base Ref: v2.16.1
>Web-Diff: https://github.com/larsxschneider/git/commit/214e9342e7
>Checkout: git fetch https://github.com/larsxschneider/git 
> fix-worktree-add-v1 && git checkout 214e9342e7
> 
> builtin/worktree.c  |  7 +--
> t/t2025-worktree-add.sh | 11 +--
> 2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/builtin/worktree.c b/builtin/worktree.c
> index 7cef5b120b..032f9b86bf 100644
> --- a/builtin/worktree.c
> +++ b/builtin/worktree.c
> @@ -345,9 +345,12 @@ static int add_worktree(const char *path, const char 
> *refname,
>* Hook failure does not warrant worktree deletion, so run hook after
>* is_junk is cleared, but do return appropriate code when hook fails.
>*/
> - if (!ret && opts->checkout)
> - ret = run_hook_le(NULL, "post-checkout", oid_to_hex(_oid),
> + if (!ret && opts->checkout) {
> + struct argv_array env = ARGV_ARRAY_INIT;
> + argv_array_pushf(, "GIT_WORK_TREE=%s", absolute_path(path));
> + ret = run_hook_le(env.argv, "post-checkout", 
> oid_to_hex(_oid),
> oid_to_hex(>object.oid), "1", NULL);

As I hit "send" I realized that I forgot to cleanup.
@Junio: Can you squash this in?

argv_array_clear();

Thanks,
Lars

> + }
> 
>   argv_array_clear(_env);
>   strbuf_release();
> diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
> index 2b95944973..d022ac0c26 100755
> --- a/t/t2025-worktree-add.sh
> +++ b/t/t2025-worktree-add.sh
> @@ -455,19 +455,26 @@ post_checkout_hook () {
>   mkdir -p .git/hooks &&
>   write_script .git/hooks/post-checkout <<-\EOF
>   echo $* >hook.actual
> + git rev-parse --show-toplevel >>hook.actual
>   EOF
> }
> 
> test_expect_success '"add" invokes post-checkout hook (branch)' '
>   post_checkout_hook &&
> - printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
> + cat >hook.expect <<-EOF &&
> + $_z40 $(git rev-parse HEAD) 1
> + $(pwd)/gumby
> + EOF
>   git worktree add gumby &&
>   test_cmp hook.expect hook.actual
> '
> 
> test_expect_success '"add" invokes post-checkout hook (detached)' '
>   post_checkout_hook &&
> - printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
> + cat >hook.expect <<-EOF &&
> + $_z40 $(git rev-parse HEAD) 1
> + $(pwd)/grumpy
> + EOF
>   git worktree add --detach grumpy &&
>   test_cmp hook.expect hook.actual
> '
> 
> base-commit: 8279ed033f703d4115bee620dccd32a9ec94d9aa
> --
> 2.16.1
> 

[PATCH v1] worktree: set worktree environment in post-checkout hook

[lars . schneider]

From: Lars Schneider 

In ade546be47 (worktree: invoke post-checkout hook (unless
--no-checkout), 2017-12-07) we taught Git to run the post-checkout hook
in worktrees. Unfortunately, the environment of the hook was not made
aware of the worktree. Consequently, a 'git rev-parse --show-toplevel'
call in the post-checkout hook would return a wrong result.

Fix this by setting the 'GIT_WORK_TREE' environment variable to make
Git calls within the post-checkout hook aware of the worktree.

Signed-off-by: Lars Schneider 
---

Hi,

I think this is a bug in Git 2.16. We noticed it because it caused a
problem in Git LFS [1]. The modified test case fails with Git 2.16 and
succeeds with this patch.

Cheers,
Lars


[1] https://github.com/git-lfs/git-lfs/issues/2848


Notes:
Base Ref: v2.16.1
Web-Diff: https://github.com/larsxschneider/git/commit/214e9342e7
Checkout: git fetch https://github.com/larsxschneider/git 
fix-worktree-add-v1 && git checkout 214e9342e7

 builtin/worktree.c  |  7 +--
 t/t2025-worktree-add.sh | 11 +--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index 7cef5b120b..032f9b86bf 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -345,9 +345,12 @@ static int add_worktree(const char *path, const char 
*refname,
 * Hook failure does not warrant worktree deletion, so run hook after
 * is_junk is cleared, but do return appropriate code when hook fails.
 */
-   if (!ret && opts->checkout)
-   ret = run_hook_le(NULL, "post-checkout", oid_to_hex(_oid),
+   if (!ret && opts->checkout) {
+   struct argv_array env = ARGV_ARRAY_INIT;
+   argv_array_pushf(, "GIT_WORK_TREE=%s", absolute_path(path));
+   ret = run_hook_le(env.argv, "post-checkout", 
oid_to_hex(_oid),
  oid_to_hex(>object.oid), "1", NULL);
+   }

argv_array_clear(_env);
strbuf_release();
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index 2b95944973..d022ac0c26 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -455,19 +455,26 @@ post_checkout_hook () {
mkdir -p .git/hooks &&
write_script .git/hooks/post-checkout <<-\EOF
echo $* >hook.actual
+   git rev-parse --show-toplevel >>hook.actual
EOF
 }

 test_expect_success '"add" invokes post-checkout hook (branch)' '
post_checkout_hook &&
-   printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
+   cat >hook.expect <<-EOF &&
+   $_z40 $(git rev-parse HEAD) 1
+   $(pwd)/gumby
+   EOF
git worktree add gumby &&
test_cmp hook.expect hook.actual
 '

 test_expect_success '"add" invokes post-checkout hook (detached)' '
post_checkout_hook &&
-   printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
+   cat >hook.expect <<-EOF &&
+   $_z40 $(git rev-parse HEAD) 1
+   $(pwd)/grumpy
+   EOF
git worktree add --detach grumpy &&
test_cmp hook.expect hook.actual
 '

base-commit: 8279ed033f703d4115bee620dccd32a9ec94d9aa
--
2.16.1