Subject: Re: [PATCH] log: diagnose empty HEAD more clearly

From: Junio C Hamano <[email-masked]>
Date: Fri, 05 Jun 2015 13:47:40 -0700

Jeff King <[email-masked]> writes:

> But if you are OK to eventually stop dying, I think this line of
> reasoning is OK.
>
>> diff --git a/builtin/log.c b/builtin/log.c
>> index 4c4e6be..3b568a1 100644
>> --- a/builtin/log.c
>> +++ b/builtin/log.c
>> @@ -148,6 +148,9 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
>>  		rev->diffopt.output_format |= DIFF_FORMAT_NO_OUTPUT;
>>  	argc = setup_revisions(argc, argv, rev, opt);
>>  
>> +	if (!rev->pending.nr && !opt->def)
>> +		die("you do not have a commit yet on your branch");
>
> Do we want to mention the name of the branch here? I guess it does not
> really matter. Perhaps "the current branch" would be better than "your
> branch", though. Maybe:
>
>   fatal: you do not have any commits yet on the current branch
>
> This message hopefully goes away in the long run, but we'll have it for
> a while.
>
>> +static void default_to_head_if_exists(struct setup_revision_opt *opt)
>> +{
>> +	unsigned char unused[20];
>> +
>> +	if (resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, unused, NULL))
>> +		opt->def = "HEAD";
>> +}
>
> This approach looks sane to me. Want to wrap it up with a commit
> message and a test?

There is an unmerged attempt jc/log-missing-default-HEAD in my
"broken-out" repository https://github.com/gitster/git; I do agree
that we should spend more cycles after deciding to error out to
give a more detailed diagnosis, but I didn't have enough energy
to bring myself do that, so I've tentatively merged your version
instead of this one.