Re: [PATCH] attr: attr.allowInvalidSource config to allow invalid revision

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 20, 2023, 16:06 UTC
Message-ID: <xmqqfs38akx5.fsf@gitster.g>
In-Reply-To: <pull.1577.git.git.1695218431033.gitgitgadget@gmail.com>

"John Cai via GitGitGadget" <gitgitgadget@gmail.com> writes:

Show 7 quoted lines

> From: John Cai <johncai86@gmail.com>
>
> 44451a2e5e (attr: teach "--attr-source=<tree>" global option to "git",
> 2023-05-06) provided the ability to pass in a treeish as the attr
> source. When a revision does not resolve to a valid tree is passed, Git
> will die. GitLab keeps bare repositories and always reads attributes
> from the default branch, so we pass in HEAD to --attr-source.

Makes sense.

> With empty repositories however, HEAD does not point to a valid treeish,
> causing Git to die. This means we would need to check for a valid
> treeish each time.

Naturally.

> To avoid this, let's add a configuration that allows
> Git to simply ignore --attr-source if it does not resolve to a valid
> tree.

Not convincing at all as to the reason why we want to do anything "to avoid this". "git log" in a repository whose HEAD does not point to a valid treeish. "git blame" dies with "no such ref: HEAD". An empty repository (more precisely, an unborn history) needs special casing if you want to present it if you do not want to spew underlying error messages to the end users *anyway*. It is unclear why seeing what commit the HEAD pointer points at (or which branch it points at for that matter) is *an* *extra* and *otherwise* *unnecessary* overhead that need to be avoided.