Use environment variables when creating signatures #6706

u-quark · 2023-12-21T21:58:58Z

When creating an action signature (e.g. for a commit author and committer) read the following environment variables that can override the configuration options:

GIT_AUTHOR_NAME is the human-readable name in the "author" field.
GIT_AUTHOR_EMAIL is the email for the "author" field.
GIT_AUTHOR_DATE is the timestamp used for the "author" field.
GIT_COMMITTER_NAME sets the human name for the "committer" field.
GIT_COMMITTER_EMAIL is the email address for the "committer" field.
GIT_COMMITTER_DATE is used for the timestamp in the "committer" field.
EMAIL is the fallback email address in case the user.email configuration value isn't set. If this isn't set, Git falls back to the system user and host names.

This is taken from the git documentation chapter "10.8 Environment Variables":

https://git-scm.com/book/en/v2/Git-Internals-Environment-Variables

This PR adds support for reading these environment variables by adding two new functions git_signature_default_author and git_signature_default_committer and deprecates the git_signature_default function.

Fixes: #3751

Prior work:

ethomson · 2023-12-22T10:20:20Z

Thank you for the PR - I agree that we need this functionality. I took a quick first pass on the changes and overall, this is an excellent PR. I will take a closer look 🔜 — thanks again.

u-quark · 2023-12-24T10:05:56Z

Hi, thanks for looking into this!

I am also keen on getting this functionality merged! Please let me know if you want a different approach of some specific implementation on this PR, I don't mind changing it.

I am not sure I recreated 100% the CI build environment but I managed to compile with clang with similar features enabled on cmake so hopefully this time CI will pass.

Cheers.

src/libgit2/signature.h

src/libgit2/signature.c

src/util/date.c

tests/libgit2/commit/signature.c

ethomson · 2023-12-22T09:38:15Z

include/git2/signature.h

@@ -56,11 +102,13 @@ GIT_EXTERN(int) git_signature_now(git_signature **out, const char *name, const c
 * based on that information.  It will return GIT_ENOTFOUND if either the
 * user.name or user.email are not set.
 *
+ * @deprecated use git_signature_default_author or git_signature_default_committer instead


Let's not deprecate it per se - at least not yet - typically, we would compile that out of builds when DEPRECATE_HARD is defined. It's usually the thing that we do before its eventual removal. Instead, let's adjust the documentation to suggest that git_signature_default_author are probably what people actually want. We can deprecate in a future release if we think that's wise.

And it may be - but I think that there are likely a lot of people who are using this API at the moment. So let's give them some time to adjust.

ethomson · 2024-01-14T00:43:54Z

A few minor tweaks requested - thanks for putting this together, I think that this is a really useful improvement. 🙏

When creating an action signature (e.g. for a commit author and committer) read the following environment variables that can override the configuration options: * `GIT_AUTHOR_NAME` is the human-readable name in the "author" field. * `GIT_AUTHOR_EMAIL` is the email for the "author" field. * `GIT_AUTHOR_DATE` is the timestamp used for the "author" field. * `GIT_COMMITTER_NAME` sets the human name for the "committer" field. * `GIT_COMMITTER_EMAIL` is the email address for the "committer" field. * `GIT_COMMITTER_DATE` is used for the timestamp in the "committer" field. * `EMAIL` is the fallback email address in case the user.email configuration value isn't set. If this isn't set, Git falls back to the system user and host names. This is taken from the git documentation chapter "10.8 Environment Variables": https://git-scm.com/book/en/v2/Git-Internals-Environment-Variables This PR adds support for reading these environment variables by adding two new functions `git_signature_default_author` and `git_signature_default_committer` and deprecates the `git_signature_default` function. Fixes: libgit2#3751 Prior work: * libgit2#4409 * libgit2#5479 * libgit2#6290

Also fix some comment formatting.

u-quark · 2024-01-14T12:28:14Z

Thanks of the review @ethomson!

csware · 2024-02-24T14:35:55Z

The usage of environment variables should always be opt-in in libgit2

Making the various pieces that create commits automatically (eg, rebase) start paying attention to the environment variables is a Big Change. For now, this is a big change in defaults; we should treat it as breaking. We don't move to this by default; we may add `from_env` or `honor_env` type of API surface in the future.

People who are doing a commit expect a unified timestamp between author and committer information when we're using the current timestamp. Provide a single function that returns both author and committer information so that they can have an identical timestamp when none is specified in the environment.

ethomson · 2024-06-14T13:16:09Z

Sorry, I've been slow to look at this. One of the things that I've found is that if you want to emulate git commit (for example), then you really want to a) look at the environment variables, but b) fall back to the same time for both author and committer if you're using the current timestamp. I think that this needs to be a single API to get both instead of individual APIs.

Per @csware 's comment, I also think that switching all the behavior of the things that produce commits internally to look at the environment variables is a Big Change that would be unexpected in a small release. I would suggest that we keep the current behavior (wherein it does not honor the GIT_AUTHOR_ and GIT_COMMITTER_ environment variables for now. We can potentially make this opt-in (you can imagine a rebase option that says that it should honor the environment variable). We could also change the behavior of libgit2 to start paying attention to environment variables by default in a future release, with an explicit opt-out. But for now, I think that it needs to remain opt-in.

I'm going to push up a commit to this based on this to adjust...

u-quark · 2024-06-17T22:17:49Z

Thanks for looking at this @ethomson, I've also been busy and didn't chase this.

I understand your points and they make sense! Both changes LGTM. I will have a closer look later this week and we should be able to merge this.

ethomson · 2024-06-18T19:48:14Z

Thanks - sorry to bring the chaotic energy and just push a commit on top of your branch. I appreciate you opening this PR and apologize again for the delay.

ethomson · 2024-07-10T07:31:12Z

Thanks again for the PR!

With libgit2/libgit2#6706 merged in we can now use libgit2 from master. Small changes were needed. This is needed in order to have stable hashes for e2e tests. Previously we needed to use a patched version from: https://github.com/u-quark/libgit2/commits/gg

u-quark · 2024-07-24T12:52:16Z

I just had some time to look into this. This is great! Works for me like a charm!

Thanks for merging this and sorry again for the late response.

ethomson requested changes Jan 14, 2024

View reviewed changes

u-quark added 4 commits January 14, 2024 11:07

Guard deprecated function definition - fix CI

47ec74b

Fix clang tests: uninitialized variable

94125fb

Address review comments

0802483

Also fix some comment formatting.

u-quark force-pushed the signature-use-env-vars branch from 42ae9fc to 0802483 Compare January 14, 2024 12:17

Remove deprecated annotation

48cb38a

ethomson added 2 commits June 14, 2024 12:49

ethomson added the feature label Jun 14, 2024

ZhangLyndon added a commit to ZhangLyndon/libgit2 that referenced this pull request Jul 7, 2024

Merge pull request libgit2#6706 from u-quark/signature-use-env-vars

1f57a89

ethomson merged commit f3518ee into libgit2:main Jul 10, 2024

ethomson mentioned this pull request Aug 27, 2024

commit: add support to take ENV variables for commit info #6290

Closed

ethomson mentioned this pull request Oct 19, 2024

Add create-signature-from-env functions, per #3751 #5479

Closed

BrewTestBot mentioned this pull request Dec 28, 2024

libgit2 1.9.0 Homebrew/homebrew-core#202651

Merged

petski mentioned this pull request Feb 10, 2025

Consider GIT_AUTHOR_EMAIL/GIT_COMMITTER_EMAIL as current author/committer tummychow/git-absorb#72

Open

tummychow mentioned this pull request Feb 17, 2025

Expose upstream git_signature_default_from_env rust-lang/git2-rs#1126

Open

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Use environment variables when creating signatures #6706

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