GeezerVison

Before: since #692, an author check that gets no message asks git whether a commit exists before it reads ignore_authors. An author on the list costs one git command more than in 2.20.4. Git commands run by commit-check --author-name (from GIT_TRACE) when the last commit is by dependabot[bot], who is on the list:

git rev-parse --git-dir
git rev-parse --verify HEAD
git log -n 1 '--pretty=format:%an' HEAD
⊘ skipped (not validated): author-name

CodSpeed reported two author benchmarks 18% slower on #692; both ran this extra lookup.

After: the same two commands as 2.20.4.

git rev-parse --git-dir
git log -n 1 '--pretty=format:%an' HEAD
⊘ skipped (not validated): author-name

How

• AuthorValidator.validate reads ignore_authors first again and looks up whether a commit exists only when the list said no. In a repository with no commits it then asks the list a second time about the identity the first commit will carry, so what fix: check the first commit's author, name author.* in the CC017 advice #692 fixed stays fixed.
• test_get_author_value_with_email_format mocks git but ran the commit lookup against the real repository. It now passes has_head=True, so nothing is looked up. Patching the lookup instead was slower than the git call by CodSpeed's count (callgrind, per run: 1.47M instructions on main, 1.92M with the extra patch, 1.26M with has_head=True).
• No change in results. Across the whole suite these two tests are the only ones whose git command count changes (1 to 0); coverage stays at 100%.