`commit_as` does not forward the given committer information

[bsdinis]

Current behavior 😯

When calling Repository::commit_as, the committer should be valid for changes to the reflog.
commit_as internally calls out to Repository::edit_references, which in turn calls Repository::committer, disregarding the committer given.

In particular, if no committer is configured in the repo (my use case, given I'm calling commit_as instead of commit), edit_references fails to edit the reflog due to a missing committer:

called `Result::unwrap()` on an `Err` value: ReferenceEdit(FileTransactionCommit(CreateOrUpdateRefLog(MissingCommitter)))

Why do I need this

I am using this in some integration tests.
For that reason, it's important to curtail gitoxide from looking into the local user config (otherwise, tests would be flaky/impossible to run in CI).
The best way I've found (so far) is to clear the config of the repo:

let mut repo: Repository = gix::init(directory: &workdir).unwrap();
let mut config_mut: SnapshotMut<'_> = repo.config_snapshot_mut();
*config = gix::config::File::default();
drop(config_mut);

Expected behavior 🤔

The committer passed into commit_as is forwarded to edit_references

Git behavior

not applicable

Steps to reproduce 🕹

With version 0.70.0:

fn main() {
    let dir = tempfile::Builder::new()
        .prefix("gitoxide-")
        .tempdir()
        .unwrap();
    let workdir = dir.path().join("repo");
    let mut repo = gix::init(&workdir).unwrap();
    let mut config_mut = repo.config_snapshot_mut();
    *config_mut = gix::config::File::default();
    drop(config_mut);

    let signature = gix::actor::Signature {
        name: bstr::BString::from("Someone"),
        email: bstr::BString::from("someone@example.org"),
        time: gix::date::Time::new(0, 0),
    };

    let blob_oid = repo.write_blob(b"some content").unwrap();
    let mut tree_editor = repo
        .edit_tree(gix::ObjectId::empty_tree(gix::hash::Kind::default()))
        .unwrap();
    tree_editor
        .upsert("file", gix::object::tree::EntryKind::Blob, blob_oid)
        .unwrap();
    let tree_id = tree_editor.write().unwrap().detach();
    repo.commit_as(
        &signature,
        &signature,
        "refs/heads/master",
        "commit",
        tree_id,
        None::<gix::ObjectId>,
    )
    .unwrap();
}

[Byron]

Thanks a lot for reporting!

I hope to get to making a fix soon.

[bsdinis]

Thank you!