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From: Junio C Hamano <gitster@pobox.com>
To: Stefan Beller <sbeller@google.com>
Cc: Johannes.Schindelin@gmx.de, git@vger.kernel.org,
	jacob.keller@gmail.com, me@ikke.info, philipoakley@iee.org
Subject: Re: [PATCH] builtin/describe.c: describe a blob
Date: Mon, 13 Nov 2017 10:33:59 +0900	[thread overview]
Message-ID: <xmqqtvxzarnc.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20171110224425.15299-2-sbeller@google.com> (Stefan Beller's message of "Fri, 10 Nov 2017 14:44:25 -0800")

Stefan Beller <sbeller@google.com> writes:

> Sometimes users are given a hash of an object and they want to
> identify it further (ex.: Use verify-pack to find the largest blobs,
> but what are these? or [1])

Thanks for finishing the topic you started.

> @@ -11,6 +11,7 @@ SYNOPSIS
>  [verse]
>  'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] [<commit-ish>...]
>  'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>]
> +'git describe' <blob>

OK.

> diff --git a/builtin/describe.c b/builtin/describe.c
> index 9e9a5ed5d4..acfd853a30 100644
> --- a/builtin/describe.c
> +++ b/builtin/describe.c
> ...
>  static void describe(const char *arg, int last_one)
>  {
> ...
> @@ -445,11 +497,18 @@ static void describe(const char *arg, int last_one)
> ...
> +	cmit = lookup_commit_reference_gently(&oid, 1);
> +
> +	if (cmit)
> +		describe_commit(&oid, &sb);
> +	else if (lookup_blob(&oid)) {
> +		if (all || tags || longformat || first_parent ||
> +		    patterns.nr || exclude_patterns.nr ||
> +		    always || dirty || broken)
> +			die(_("options not available for describing blobs"));
> +		describe_blob(oid, &sb);

I am not sure if I agree with some of them.

> +	} else
> +		die(_("%s is neither a commit nor blob"), arg);

This side I would agree with, though.

The caller of the describe() function is either

 * 'git describe<RETURN>' makes a single call to it with "HEAD" and
   exits; or
 * 'git describe A B C...' makes one call to it for each of these
   command line arguments.

And 'git describe <blob>' code is most likely trigger from the latter,
as it is not likely for HEAD to be pointing at a blob.

    $ blob=$(git rev-parse master:Makefile)
    $ git describe --always master $blob

and trigger the above check.  Is the check against "always" useful,
or is it better to simply ignore it while describing $blob, but
still keeping it in effect while describing 'master'?

The 'dirty' and 'broken' check is redundant because we would have
already errored out if either of them is set before calling describe()
on user-supplied object names.

If I understand the way "describe <blob>" works correctly, it
traverses the history with objects, doing a moral equivalent of
"rev-list --objects", stops when it finds the blob object with the
given name, and when it stops, it knows the commit object that
contains the blob and path in that commit to the blob.  Then the
commit is described to be a human-readable string, so that the path
can be concatenated after it.

Aren't these options that affect how a commit object is described in
effect and useful when you do the "internal" describe of the commit
you found the blob object in?  IOW, wouldn't this

    $ git describe --exclude='*-wip' $blob

make sure that in its output $commit:$path, $commit is not described
in terms of any "wip" refs?


  reply	other threads:[~2017-11-13  1:34 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-28  0:44 [RFC PATCH 0/3] git-describe <blob> ? Stefan Beller
2017-10-28  0:45 ` [PATCH 1/3] list-objects.c: factor out traverse_trees_and_blobs Stefan Beller
2017-10-28  0:45   ` [PATCH 2/3] revision.h: introduce blob/tree walking in order of the commits Stefan Beller
2017-10-28 17:20     ` Johannes Schindelin
2017-10-29  3:22       ` Stefan Beller
2017-10-29  3:23         ` Stefan Beller
2017-10-29  3:43           ` Junio C Hamano
2017-10-28  0:45   ` [PATCH 3/3] builtin/describe: describe blobs Stefan Beller
2017-10-28 17:32     ` Johannes Schindelin
2017-10-28 22:47       ` Jacob Keller
2017-10-29  3:28       ` Stefan Beller
2017-10-29 12:02         ` Kevin Daudt
2017-10-29 12:07         ` Johannes Schindelin
2017-10-28 17:15   ` [PATCH 1/3] list-objects.c: factor out traverse_trees_and_blobs Johannes Schindelin
2017-10-29  3:13     ` Stefan Beller
2017-10-28 16:04 ` [RFC PATCH 0/3] git-describe <blob> ? Johannes Schindelin
2017-10-31  0:33 ` [PATCH 0/7] git-describe <blob> Stefan Beller
2017-10-31  0:33   ` [PATCH 1/7] list-objects.c: factor out traverse_trees_and_blobs Stefan Beller
2017-10-31  6:07     ` Junio C Hamano
2017-10-31  0:33   ` [PATCH 2/7] revision.h: introduce blob/tree walking in order of the commits Stefan Beller
2017-10-31  6:57     ` Junio C Hamano
2017-10-31 18:12       ` Stefan Beller
2017-10-31  0:33   ` [PATCH 3/7] builtin/describe.c: rename `oid` to avoid variable shadowing Stefan Beller
2017-10-31  8:15     ` Jacob Keller
2017-10-31  0:33   ` [PATCH 4/7] builtin/describe.c: print debug statements earlier Stefan Beller
2017-10-31  7:03     ` Junio C Hamano
2017-10-31 19:05       ` Stefan Beller
2017-10-31  0:33   ` [PATCH 5/7] builtin/describe.c: factor out describe_commit Stefan Beller
2017-10-31  0:33   ` [PATCH 6/7] builtin/describe.c: describe a blob Stefan Beller
2017-10-31  6:25     ` Junio C Hamano
2017-10-31 19:16       ` Stefan Beller
2017-11-01  3:34         ` Junio C Hamano
2017-11-01 20:58           ` Stefan Beller
2017-11-02  1:53             ` Junio C Hamano
2017-11-02  4:23               ` Junio C Hamano
2017-11-04 21:15                 ` Philip Oakley
2017-11-05  6:28                   ` Junio C Hamano
2017-11-06 23:50                     ` Philip Oakley
2017-11-09 20:30                       ` Stefan Beller
2017-11-10  0:25                         ` Philip Oakley
2017-11-10  1:24                           ` Junio C Hamano
2017-11-10 22:44                             ` [PATCH 0/1] describe a blob: with better docs Stefan Beller
2017-11-10 22:44                               ` [PATCH] builtin/describe.c: describe a blob Stefan Beller
2017-11-13  1:33                                 ` Junio C Hamano [this message]
2017-11-14 23:37                                   ` Stefan Beller
2017-11-20 15:22                             ` [PATCH 6/7] " Philip Oakley
2017-11-20 18:18                               ` Philip Oakley
2017-11-01  3:44         ` Junio C Hamano
2017-10-31  0:33   ` [PATCH 7/7] t6120: fix typo in test name Stefan Beller
2017-11-01  1:21     ` Junio C Hamano
2017-11-01 18:13       ` Stefan Beller
2017-11-02  1:36       ` Junio C Hamano
2017-10-31 21:18   ` [PATCHv2 0/7] git describe blob Stefan Beller
2017-10-31 21:18     ` [PATCHv2 1/7] list-objects.c: factor out traverse_trees_and_blobs Stefan Beller
2017-11-01  3:46       ` Junio C Hamano
2017-10-31 21:18     ` [PATCHv2 2/7] revision.h: introduce blob/tree walking in order of the commits Stefan Beller
2017-11-01  3:50       ` Junio C Hamano
2017-11-01 12:26         ` Johannes Schindelin
2017-11-01 12:37           ` Junio C Hamano
2017-11-01 19:37             ` Stefan Beller
2017-11-01 22:08               ` Johannes Schindelin
2017-11-01 22:19                 ` Stefan Beller
2017-11-01 22:39                   ` Johannes Schindelin
2017-11-01 22:46                     ` Stefan Beller
2017-11-01 21:36             ` Johannes Schindelin
2017-11-01 21:39               ` Jeff King
2017-11-01 22:33                 ` Johannes Schindelin
2017-11-02  1:20                   ` Junio C Hamano
2017-10-31 21:18     ` [PATCHv2 3/7] builtin/describe.c: rename `oid` to avoid variable shadowing Stefan Beller
2017-10-31 21:18     ` [PATCHv2 4/7] builtin/describe.c: print debug statements earlier Stefan Beller
2017-10-31 21:31       ` Eric Sunshine
2017-10-31 21:18     ` [PATCHv2 5/7] builtin/describe.c: factor out describe_commit Stefan Beller
2017-10-31 21:18     ` [PATCHv2 6/7] builtin/describe.c: describe a blob Stefan Beller
2017-10-31 21:49       ` Eric Sunshine
2017-11-01 19:51         ` Stefan Beller
2017-11-01  4:11       ` Junio C Hamano
2017-11-01 12:32         ` Johannes Schindelin
2017-11-01 17:59           ` Stefan Beller
2017-11-01 21:05             ` Jacob Keller
2017-11-01 22:12               ` Johannes Schindelin
2017-11-01 22:21                 ` Stefan Beller
2017-11-01 22:41                   ` Johannes Schindelin
2017-11-01 22:53                     ` Stefan Beller
2017-11-02  6:05                     ` Jacob Keller
2017-11-03  5:18                       ` Junio C Hamano
2017-11-03  6:55                         ` Jacob Keller
2017-11-03 15:02                           ` Junio C Hamano
2017-11-02  7:23                     ` Andreas Schwab
2017-11-02 18:18                       ` Stefan Beller
2017-11-03 12:05                         ` Johannes Schindelin
2017-11-01 21:28         ` Stefan Beller
2017-10-31 21:18     ` [PATCHv2 7/7] t6120: fix typo in test name Stefan Beller
2017-11-01  5:14     ` [PATCHv2 0/7] git describe blob Junio C Hamano
2017-11-02 19:41     ` [PATCHv3 " Stefan Beller
2017-11-02 19:41       ` [PATCHv3 1/7] t6120: fix typo in test name Stefan Beller
2017-11-02 19:41       ` [PATCHv3 2/7] list-objects.c: factor out traverse_trees_and_blobs Stefan Beller
2017-11-02 19:41       ` [PATCHv3 3/7] revision.h: introduce blob/tree walking in order of the commits Stefan Beller
2017-11-14 19:52         ` Jonathan Tan
2017-11-02 19:41       ` [PATCHv3 4/7] builtin/describe.c: rename `oid` to avoid variable shadowing Stefan Beller
2017-11-02 19:41       ` [PATCHv3 5/7] builtin/describe.c: print debug statements earlier Stefan Beller
2017-11-14 19:55         ` Jonathan Tan
2017-11-14 20:00           ` Stefan Beller
2017-11-02 19:41       ` [PATCHv3 6/7] builtin/describe.c: factor out describe_commit Stefan Beller
2017-11-02 19:41       ` [PATCHv3 7/7] builtin/describe.c: describe a blob Stefan Beller
2017-11-14 20:02         ` Jonathan Tan
2017-11-14 20:40           ` Stefan Beller
2017-11-14 21:17             ` Jonathan Tan
2017-11-03  0:23       ` [PATCHv3 0/7] git describe blob Jacob Keller
2017-11-03  1:46         ` Junio C Hamano
2017-11-03  2:29           ` Stefan Beller

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