Re: Re* Git without morning coffee

> Junio C Hamano <gitster@pobox.com> writes:
> 
>> Junio C Hamano <gitster@pobox.com> writes:
>>
>>> Michael J Gruber <git@drmicha.warpmail.net> writes:
>>>
>>>> git merge ":/Merge branch 'jk/generation-numbers' into pu"
>>>> fatal: ':/Merge branch 'jk/generation-numbers' into pu' does not point
>>>> to a commit
>>>> # Huh?
>>>
>>> Interesting.
>>
>> This is because 1c7b76b (Build in merge, 2008-07-07) grabs the name of the
>> commit to be merged using peel_to_type(), which was defined in 8177631
>> (expose a helper function peel_to_type()., 2007-12-24) in terms of
>> get_sha1_1(). It understands $commit~$n, $commit^$n and $ref@{$nth}, but
>> does not understand :/$str, $treeish:$path, and :$stage:$path.
> 
> -- >8 --
> Subject: Allow git merge ":/<pattern>"
> 
> It probably is not such a good idea to use ":/<pattern>" to specify which
> commit to merge, as ":/<pattern>" can often hit unexpected commits, but
> somebody tried it and got a nonsense error message:
> 
> 	fatal: ':/Foo bar' does not point to a commit
> 
> So here is a for-the-sake-of-consistency update that is fairly useless
> that allows users to carefully try not shooting in the foot.

> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  builtin/merge.c |   19 ++++++++++++++-----
>  sha1_name.c     |    6 ------
>  2 files changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/builtin/merge.c b/builtin/merge.c
> index ab4077f..ee56974 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -403,6 +403,16 @@ static void finish(const unsigned char *new_head, const char *msg)
>  	strbuf_release(&reflog_message);
>  }
>  
> +static struct object *want_commit(const char *name)
> +{
> +	struct object *obj;
> +	unsigned char sha1[20];
> +	if (get_sha1(name, sha1))
> +		return NULL;
> +	obj = parse_object(sha1);
> +	return peel_to_type(name, 0, obj, OBJ_COMMIT);
> +}
> +
>  /* Get the name for the merge commit's message. */
>  static void merge_name(const char *remote, struct strbuf *msg)
>  {
> @@ -418,7 +428,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
>  	remote = bname.buf;
>  
>  	memset(branch_head, 0, sizeof(branch_head));
> -	remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
> +	remote_head = want_commit(remote);
>  	if (!remote_head)
>  		die(_("'%s' does not point to a commit"), remote);
>  
> @@ -1124,7 +1134,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
>  		if (!allow_fast_forward)
>  			die(_("Non-fast-forward commit does not make sense into "
>  			    "an empty head"));
> -		remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
> +		remote_head = want_commit(argv[0]);
>  		if (!remote_head)
>  			die(_("%s - not something we can merge"), argv[0]);
>  		read_empty(remote_head->sha1, 0);
> @@ -1170,7 +1180,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
>  		struct object *o;
>  		struct commit *commit;
>  
> -		o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
> +		o = want_commit(argv[i]);
>  		if (!o)
>  			die(_("%s - not something we can merge"), argv[i]);
>  		commit = lookup_commit(o->sha1);
> @@ -1238,8 +1248,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
>  		if (have_message)
>  			strbuf_addstr(&msg,
>  				" (no commit created; -m option ignored)");
> -		o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
> -			0, NULL, OBJ_COMMIT);
> +		o = want_commit(sha1_to_hex(remoteheads->item->object.sha1));
>  		if (!o)
>  			return 1;
>  
> diff --git a/sha1_name.c b/sha1_name.c
> index ff5992a..653b065 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -501,12 +501,6 @@ struct object *peel_to_type(const char *name, int namelen,
>  {
>  	if (name && !namelen)
>  		namelen = strlen(name);
> -	if (!o) {
> -		unsigned char sha1[20];
> -		if (get_sha1_1(name, namelen, sha1))
> -			return NULL;
> -		o = parse_object(sha1);
> -	}
>  	while (1) {
>  		if (!o || (!o->parsed && !parse_object(o->sha1)))
>  			return NULL;