| Message ID | pull.1457.v2.git.1673293508399.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 772f8ff826fcb15cba94bfd8f23eb0917f3e9edc |
| Headers | show |
| Series | [v2] githooks: discuss Git operations in foreign repositories | expand |
On Mon, Jan 9, 2023 at 1:45 PM Eric Sunshine via GitGitGadget <gitgitgadget@gmail.com> wrote: > Documentation/githooks.txt | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt > index a16e62bc8c8..62908602e7b 100644 > --- a/Documentation/githooks.txt > +++ b/Documentation/githooks.txt > @@ -27,6 +27,18 @@ repository. An exception are hooks triggered during a push ('pre-receive', > 'update', 'post-receive', 'post-update', 'push-to-checkout') which are always > executed in $GIT_DIR. > > +Environment variables, such as `GIT_DIR`, `GIT_WORK_TREE`, etc., are exported > +so that Git commands run by the hook can correctly locate the repository. If > +your hook needs to invoke Git commands in a foreign repository or in a > +different working tree of the same repository, then it should clear these > +environment variables so they do not interfere with Git operations at the > +foreign location. For example: > + > +------------ > +local_desc=$(git describe) > +foreign_desc=$(unset $(git rev-parse --local-env-vars); git -C ../foreign-repo describe) > +------------ This looks good to me! Thank you! (And I'm sorry about top-posting *again*! I think I have the hang of it now.)
On Mon, Jan 09, 2023 at 07:45:08PM +0000, Eric Sunshine via GitGitGadget wrote: > Recommended best-practice[1,2,3,4,5,6] for avoiding this problem is for > the hook to ensure that Git variables are unset before invoking Git > commands in foreign repositories or other worktrees: > > unset $(git rev-parse --local-env-vars) > > However, this advice is not documented anywhere. Rectify this > shortcoming by mentioning it in githooks.txt documentation. > > [1]: https://lore.kernel.org/git/YFuHd1MMlJAvtdzb@coredump.intra.peff.net/ > [2]: https://lore.kernel.org/git/20200228190218.GC1408759@coredump.intra.peff.net/ > [3]: https://lore.kernel.org/git/20190516221702.GA11784@sigill.intra.peff.net/ > [4]: https://lore.kernel.org/git/20190422162127.GC9680@sigill.intra.peff.net/ > [5]: https://lore.kernel.org/git/20180716183942.GB22298@sigill.intra.peff.net/ > [6]: https://lore.kernel.org/git/20150203163235.GA9325@peff.net/ Boy, I'm like a broken record. The patch here looks good to me. The problem is wider than just hooks, but it seems like that's going to be a common place for people to get caught by it. So certainly this is going in the right direction. The other place I've run into it is writing a script meant to be run as an external command. E.g., running this: git --git-dir=/some/path my-external-command means that "my-external-command" is going to have $GIT_DIR set. If it wants to operate on another repository it needs to take care to clear that from the environment. -Peff
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index a16e62bc8c8..62908602e7b 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -27,6 +27,18 @@ repository. An exception are hooks triggered during a push ('pre-receive', 'update', 'post-receive', 'post-update', 'push-to-checkout') which are always executed in $GIT_DIR. +Environment variables, such as `GIT_DIR`, `GIT_WORK_TREE`, etc., are exported +so that Git commands run by the hook can correctly locate the repository. If +your hook needs to invoke Git commands in a foreign repository or in a +different working tree of the same repository, then it should clear these +environment variables so they do not interfere with Git operations at the +foreign location. For example: + +------------ +local_desc=$(git describe) +foreign_desc=$(unset $(git rev-parse --local-env-vars); git -C ../foreign-repo describe) +------------ + Hooks can get their arguments via the environment, command-line arguments, and stdin. See the documentation for each hook below for details.