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From: "René Scharfe" <l.s.r@web•de>
To: Jeff King <peff@peff•net>
Cc: phillip.wood@dunelm•org.uk, Cheng <prophecheng@stu•pku.edu.cn>,
	git@vger•kernel.org
Subject: Re: [PATCH 2/5] describe: error if blob not found
Date: Tue, 19 Aug 2025 20:32:03 +0200	[thread overview]
Message-ID: <efa90ac9-8190-4af5-9e63-ffbd04c3c9c1@web.de> (raw)
In-Reply-To: <20250818210125.GB1024556@coredump.intra.peff.net>

On 8/18/25 11:01 PM, Jeff King wrote:
> If describe_blob() does not find the blob in question, it returns an
> empty strbuf, and we print an empty line. This differs from
> describe_commit(), which always either returns an answer or calls die()
> itself. As the blob function was bolted onto the command afterwards, I
> think its behavior is not intentional, and it is just a bug that it does
> not report an error.
> 
> Signed-off-by: Jeff King <peff@peff•net>
> ---
> This one is perhaps the most controversial, as it is a change in
> behavior. But the current behavior just really seems like a bug to me.
> 
> Unlike what René posted earlier, I didn't record the dst strbuf's
> original size and compare against that. This is a static function with
> only one caller that passes in an empty strbuf, so being overly
> defensive didn't seem worth it

Makes sense.

> (arguably these functions should just
> return an allocated buffer anyway).

Or even print results directly.

>  builtin/describe.c  | 3 +++
>  t/t6120-describe.sh | 6 ++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/builtin/describe.c b/builtin/describe.c
> index 383d3e6b9a..06e413d937 100644
> --- a/builtin/describe.c
> +++ b/builtin/describe.c
> @@ -535,6 +535,9 @@ static void describe_blob(const struct object_id *oid, struct strbuf *dst)
>  	reset_revision_walk();
>  	release_revisions(&revs);
>  	strvec_clear(&args);
> +
> +	if (!dst->len)
> +		die(_("blob '%s' not reachable from HEAD"), oid_to_hex(oid));

I like the clarity and precision of this message. 

The rest of the patches look good to me as well.  The first is a nice
little bonus.

René

>  }
>  
>  static void describe(const char *arg, int last_one)
> diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
> index 256ccaefb7..470631d17d 100755
> --- a/t/t6120-describe.sh
> +++ b/t/t6120-describe.sh
> @@ -409,6 +409,12 @@ test_expect_success 'describe tag object' '
>  	test_grep "fatal: test-blob-1 is neither a commit nor blob" actual
>  '
>  
> +test_expect_success 'describe an unreachable blob' '
> +	blob=$(echo not-found-anywhere | git hash-object -w --stdin) &&
> +	test_must_fail git describe $blob 2>actual &&
> +	test_grep "blob .$blob. not reachable from HEAD" actual
> +'
> +
>  test_expect_success ULIMIT_STACK_SIZE 'name-rev works in a deep repo' '
>  	i=1 &&
>  	while test $i -lt 8000


  parent reply	other threads:[~2025-08-19 18:32 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-13  0:23 Potential Null Pointer Dereference detected by static analysis tool Cheng
2025-08-13 13:19 ` Phillip Wood
2025-08-14 23:26   ` Jeff King
2025-08-15 15:49     ` Phillip Wood
2025-08-17  9:27     ` René Scharfe
2025-08-18  4:48       ` Jeff King
2025-08-18  5:05         ` Jeff King
2025-08-18 19:56           ` René Scharfe
2025-08-18 20:21             ` Jeff King
2025-08-18 20:56               ` Jeff King
2025-08-18 20:58               ` [PATCH 0/5] fix segfault and other oddities describing blobs Jeff King
2025-08-18 20:59                 ` [PATCH 1/5] describe: pass oid struct by const pointer Jeff King
2025-08-18 21:05                   ` Junio C Hamano
2025-08-18 21:01                 ` [PATCH 2/5] describe: error if blob not found Jeff King
2025-08-18 21:12                   ` Junio C Hamano
2025-08-19  8:05                     ` Patrick Steinhardt
2025-08-19 18:32                   ` René Scharfe [this message]
2025-08-18 21:01                 ` [PATCH 3/5] describe: catch unborn branch in describe_blob() Jeff King
2025-08-18 21:19                   ` Junio C Hamano
2025-08-18 23:07                     ` Jeff King
2025-08-18 21:03                 ` [PATCH 4/5] describe: handle blob traversal with no commits Jeff King
2025-08-19  8:05                   ` Patrick Steinhardt
2025-08-19 16:59                     ` Jeff King
2025-08-20  4:34                       ` Patrick Steinhardt
2025-08-20  6:30                         ` [replacement PATCH " Jeff King
2025-08-18 21:04                 ` [PATCH 5/5] describe: pass commit to describe_commit() Jeff King
2025-08-19  8:05                   ` Patrick Steinhardt
2025-08-19 17:02                     ` Jeff King

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