Re: Possible bug: Empty magic word list in pathspec is handled differently in short vs. long form

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 19, 2025, 17:11 UTC
Message-ID: <xmqqr03tg8q1.fsf@gitster.g>
In-Reply-To: <216a7288-b599-4333-ba62-10665d6a94d8@anselmschueler.com>

Anselm Schüler <mail@anselmschueler.com> writes:

> If you run git diff for a pathspec with an empty magic word/symbol
> list in short form (prefixed by ::) and in long form (prefixed by
> :():), you get different results.

The short form is prefixed by a ":" and optionally ends by a ":", but the optional termination may not be required when there is no ambiguity (e.g. ":/!path" is "from the top, not matching "path", as "p" cannot be a magic signature; ":/:!path" is "from the top, matching "!path", as the set of magic signatures ends with the second disambiguating colon).

The long form is prefixed by a ":(" and ends by a ")".

Show 25 quoted lines

> Here’s an example use of git that illustrates this:
>
> ~☭ mkdir gittest
> ~☭ y gittest/
> ~/gittest☭ git init
> Initialized empty Git repository in /home/anselmschueler/gittest/.git/
> ~/gittest (b0)☭ uuidgen >file
> ~/gittest (b0)☭ git add file && git commit -m "$(read)"
> read> initial commit
> [b0 (root-commit) cd3bd43] initial commit
>  1 file changed, 1 insertion(+)
>  create mode 100644 file
> ~/gittest (b0)☭ uuidgen >file
> ~/gittest (b0)☭ git diff -- "::file"
>
> file
> ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
>
> ───┐
> 1: │
> ───┘
> 66d18ffa-1128-42a5-8d4e-f9d75eb86b92
> 9acea2b5-50a6-4f87-ae1a-64019a93e55e
> ~/gittest (b0)☭ git diff -- ":():file"
> ~/gittest (b0)☭

Doesn't ":():file" ask for a match for the pattern ":file", with a leading colon?