Re: [PATCH] contrib/git-svn: fix UUID reading w/pre-1.2 svn; fetch args

[Junio C Hamano <junkio@cox.net>]

Eric Wong <normalperson@yhbt.net> writes:

> Junio: please don't apply this patch to git.git just yet.  It seems fine
> to me, but I haven't tested it heavily yet (Yann can help me, I hope :)
> I hardly slept the past few days and I may have broken something badly
> (it pasts all the tests, though).

I won't be applying it then.

I think this part is wrong.

> @@ -922,7 +930,9 @@ sub git_commit {
>  	}
>  	my @update_ref = ('git-update-ref',"refs/remotes/$GIT_SVN",$commit);
>  	if (my $primary_parent = shift @exec_parents) {
> -		push @update_ref, $primary_parent;
> +		if (!system('git-rev-parse',"refs/remotes/$GIT_SVN")){
> +			push @update_ref, $primary_parent;
> +		}

I think you are trying to see if you have .git/refs/remotes/foo,
and I think you actually have tried it to determine that is the
case.

But "git-rev-parse refs/remotes/foo" dies not because there is
no valid file .git/refs/remotes/foo that records SHA1 of an
existing commit.  If there is refs/remotes/foo file, it thinks
you have asked for it and gives it back happily.

A demonstration:

	$ cd /var/tmp/ && rm -fr junk && mkdir junk && cd junk
        $ git init-db
	defaulting to local storage area
        $ git-rev-parse refs/remotes/foo ; echo $?
        refs/remotes/foo
        fatal: 'refs/remotes/foo': No such file or directory
        128
        $ mkdir -p refs/remotes/foo
        $ ls -a
        ./  ../  .git/	refs/
        $ git-rev-parse refs/remotes/foo; echo $?
        refs/remotes/foo
        0

If you are trying to see if there is such a ref, I would do
this:

	$ git-rev-parse --verify refs/remotes/foo^0
        git-rev-parse --verify refs/remotes/foo^0
        fatal: Needed a single revision
	128

The --verify flag makes sure that the argument resolves to a
valid 40-hexadigit string (note that it does not verify if that
object actually exists), so asking for zeroth parent makes sure
you are dealing with a ref that actually points at a commit
object that exists.