From: shejialuo Date: Thu, 27 Feb 2025 16:06:40 +0000 (+0800) Subject: packed-backend: check if header starts with "# pack-refs with: " X-Git-Tag: v2.50.0-rc0~176^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=515579756c8d23ea2f3c6386a9333ecbe84d8a08;p=thirdparty%2Fgit.git packed-backend: check if header starts with "# pack-refs with: " We always write a space after "# pack-refs with:" but we don't align with this rule in the "create_snapshot" method where we would check whether header starts with "# pack-refs with:". It might seem that we should undoubtedly tighten this rule, however, we don't have any technical documentation about this and there is a possibility that we would break the compatibility for other third-party libraries. By investigating influential third-party libraries, we could conclude how these libraries handle the header of "packed-refs" file: 1. libgit2 is fine and always writes the space. It also expects the whitespace to exist. 2. JGit does not expect th header to have a trailing space, but expects the "peeled" capability to have a leading space, which is mostly equivalent because that capability is typically the first one we write. It always writes the space. 3. gitoxide expects the space t exist and writes it. 4. go-git doesn't create the header by default. As many third-party libraries expect a single space after "# pack-refs with:", if we forget to write the space after the colon, "create_snapshot" won't catch this. And we would break other re-implementations. So, we'd better tighten the rule by checking whether the header starts with "# pack-refs with: ". Mentored-by: Patrick Steinhardt Mentored-by: Karthik Nayak Signed-off-by: shejialuo Signed-off-by: Junio C Hamano --- diff --git a/refs/packed-backend.c b/refs/packed-backend.c index 1fba804a2a..eaa8746f3e 100644 --- a/refs/packed-backend.c +++ b/refs/packed-backend.c @@ -694,7 +694,7 @@ static struct snapshot *create_snapshot(struct packed_ref_store *refs) tmp = xmemdupz(snapshot->buf, eol - snapshot->buf); - if (!skip_prefix(tmp, "# pack-refs with:", (const char **)&p)) + if (!skip_prefix(tmp, "# pack-refs with: ", (const char **)&p)) die_invalid_line(refs->path, snapshot->buf, snapshot->eof - snapshot->buf);