threads / bug / 61570

[bug report] git diff --relative not doing well with worktree in hooks

Subject: [bug report] git diff --relative not doing well with worktree in hooks

## tl;dr

5 messages between May 31, 2024 and Jun 3, 2024.

replies: 4people: 3as markdown or json

Antoine Bolvy· May 31, 2024, 11:38 UTC · lore
Hello,

I noticed a weird behavior when using git diff --relative with worktrees and hooks. When called from a pre-commit hook from a worktree, the relative option has no effect.

Here is how to reproduce the issue:

```bash mkdir hook-repro && cd hook-repro git init test && cd test mkdir folder && touch folder/.gitkeep && git add folder git commit -m 'init' cat <<EOF > .git/hooks/pre-commit #!/bin/bash

cd folder || exit
pwd # display the current working directory

git diff --cached --relative --name-only EOF chmod +x .git/hooks/pre-commit ```

```bash echo "foo" > folder/bar git add folder git commit -m "test" ```

Displays ``` /home/arch/git/awfus/hook-repro/test/folder bar ```

Now creating a worktree:

```bash git worktree add ../worktree && cd ../worktree echo "bar" > folder/foo git add folder git commit -m "worktree" ```

Displays ``` /home/arch/git/awfus/hook-repro/worktree/folder folder/foo ```

The path is no longer show relative. This causes issues with more complex scripts.

Git version: 2.45.0 (x86_64) on Arch Linux, shell is zsh (bash for the hook script)

Let me know if you need any more information :)
Eric Sunshine· May 31, 2024, 21:42 UTC · re: Antoine Bolvy · lore

Re: [bug report] git diff --relative not doing well with worktree in hooks

On Fri, May 31, 2024 at 7:38 AM Antoine Bolvy <antoine.bolvy@gmail.com> wrote:
Show 16 quoted lines
> I noticed a weird behavior when using git diff --relative with worktrees and
> hooks. When called from a pre-commit hook from a worktree, the relative option
> has no effect.
>
> [main tree] Displays
> ```
> /home/arch/git/awfus/hook-repro/test/folder
> bar
> ```
> [in worktree] Displays
> ```
> /home/arch/git/awfus/hook-repro/worktree/folder
> folder/foo
> ```
> The path is no longer show relative. This causes issues with more complex
> scripts.

I'm not sure there's a satisfactory resolution here. Your hook is running afoul of the environment variables Git sets up when the hook is run outside of the "main" worktree.

If you change your hook from:
    #!/bin/bash
    cd folder || exit
    pwd # display the current working directory
    git diff --cached --relative --name-only
to:
    #!/bin/bash
    cd folder || exit
    pwd # display the current working directory
    unset $(git rev-parse --local-env-vars)
    git diff --cached --relative --name-only
then it works as expected.
The relevant portion from the "githooks" manual page is:
    Environment variables, such as GIT_DIR, GIT_WORK_TREE, etc., are
    exported so that Git commands run by the hook can correctly locate
    the repository. If your hook needs to invoke Git commands in a
    foreign repository or in a different working tree of the same
    repository, then it should clear these environment variables so
    they do not interfere with Git operations at the foreign
    location. For example:
        local_desc=$(git describe)
        foreign_desc=$(unset $(git rev-parse --local-env-vars); git -C
../foreign-repo describe)
Antoine Bolvy· Jun 3, 2024, 08:38 UTC · re: Eric Sunshine · lore

Re: [bug report] git diff --relative not doing well with worktree in hooks

Show 16 quoted lines
> If you change your hook from:
>
>    #!/bin/bash
>    cd folder || exit
>    pwd # display the current working directory
>    git diff --cached --relative --name-only
>
>to:
>
>    #!/bin/bash
>    cd folder || exit
>    pwd # display the current working directory
>    unset $(git rev-parse --local-env-vars)
>    git diff --cached --relative --name-only
>
>then it works as expected.
It seems that unsetting GIT_DIR only is enough to make it work:
    #!/bin/bash
    cd folder || exit
    pwd # display the current working directory
    unset GIT_DIR
    git diff --cached --relative --name-only
Thanks for the help and pointing me to the right documentation!

Antoine BOLVY +33(0)675455349 • https://saveman71.com

On Fri, May 31, 2024 at 11:42 PM Eric Sunshine <sunshine@sunshineco.com> wrote:
Show 53 quoted lines
>
> On Fri, May 31, 2024 at 7:38 AM Antoine Bolvy <antoine.bolvy@gmail.com> wrote:
> > I noticed a weird behavior when using git diff --relative with worktrees and
> > hooks. When called from a pre-commit hook from a worktree, the relative option
> > has no effect.
> >
> > [main tree] Displays
> > ```
> > /home/arch/git/awfus/hook-repro/test/folder
> > bar
> > ```
> > [in worktree] Displays
> > ```
> > /home/arch/git/awfus/hook-repro/worktree/folder
> > folder/foo
> > ```
> > The path is no longer show relative. This causes issues with more complex
> > scripts.
>
> I'm not sure there's a satisfactory resolution here. Your hook is
> running afoul of the environment variables Git sets up when the hook
> is run outside of the "main" worktree.
>
> If you change your hook from:
>
>     #!/bin/bash
>     cd folder || exit
>     pwd # display the current working directory
>     git diff --cached --relative --name-only
>
> to:
>
>     #!/bin/bash
>     cd folder || exit
>     pwd # display the current working directory
>     unset $(git rev-parse --local-env-vars)
>     git diff --cached --relative --name-only
>
> then it works as expected.
>
> The relevant portion from the "githooks" manual page is:
>
>     Environment variables, such as GIT_DIR, GIT_WORK_TREE, etc., are
>     exported so that Git commands run by the hook can correctly locate
>     the repository. If your hook needs to invoke Git commands in a
>     foreign repository or in a different working tree of the same
>     repository, then it should clear these environment variables so
>     they do not interfere with Git operations at the foreign
>     location. For example:
>
>         local_desc=$(git describe)
>         foreign_desc=$(unset $(git rev-parse --local-env-vars); git -C
> ../foreign-repo describe)
Phillip Wood· Jun 3, 2024, 09:29 UTC · re: Eric Sunshine · lore

Re: [bug report] git diff --relative not doing well with worktree in hooks

Hi Eric
On 31/05/2024 22:42, Eric Sunshine wrote:
Show 17 quoted lines
> On Fri, May 31, 2024 at 7:38 AM Antoine Bolvy <antoine.bolvy@gmail.com> wrote:
>> The path is no longer show relative. This causes issues with more complex
>> scripts.
> 
> I'm not sure there's a satisfactory resolution here. Your hook is
> running afoul of the environment variables Git sets up when the hook
> is run outside of the "main" worktree.
> [...] 
> The relevant portion from the "githooks" manual page is:
> 
>      Environment variables, such as GIT_DIR, GIT_WORK_TREE, etc., are
>      exported so that Git commands run by the hook can correctly locate
>      the repository. If your hook needs to invoke Git commands in a
>      foreign repository or in a different working tree of the same
>      repository, then it should clear these environment variables so
>      they do not interfere with Git operations at the foreign
>      location. For example:

Maybe I'm missing something but in Antonine's example the hook is being run in the same worktree as the "git commit" - we're changing into a subdirectory of the worktree, not changing to a different worktree so why doesn't it work?

Best Wishes
Phillip
Eric Sunshine· Jun 3, 2024, 21:59 UTC · re: Phillip Wood · lore

Re: [bug report] git diff --relative not doing well with worktree in hooks

On Mon, Jun 3, 2024 at 5:30 AM Phillip Wood <phillip.wood123@gmail.com> wrote:
Show 19 quoted lines
> On 31/05/2024 22:42, Eric Sunshine wrote:
> > I'm not sure there's a satisfactory resolution here. Your hook is
> > running afoul of the environment variables Git sets up when the hook
> > is run outside of the "main" worktree.
> > [...]
> > The relevant portion from the "githooks" manual page is:
> >
> >      Environment variables, such as GIT_DIR, GIT_WORK_TREE, etc., are
> >      exported so that Git commands run by the hook can correctly locate
> >      the repository. If your hook needs to invoke Git commands in a
> >      foreign repository or in a different working tree of the same
> >      repository, then it should clear these environment variables so
> >      they do not interfere with Git operations at the foreign
> >      location. For example:
>
> Maybe I'm missing something but in Antonine's example the hook is being
> run in the same worktree as the "git commit" - we're changing into a
> subdirectory of the worktree, not changing to a different worktree so
> why doesn't it work?

It's been a while since I looked at the code, but my recollection is that the hook-running machinery unconditionally sets the environment variables whenever the directory in which the hook is being run is not the "main" worktree. This is the case whether his hook runs at the root of the worktree or in a subdirectory.

It's quite possible that this behavior is entirely accidental since the hook-running machinery existed long before multiple-worktree support was added, and it may be that the hook-running machinery simply wasn't revisited when worktree support was implemented. So, perhaps a "satisfactory resolution" is to "fix" the hook-running machinery itself to avoid setting those environment variables unnecessarily.

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