Re: Friendly refspecs

[Jeff King <peff@peff.net>]

On Wed, Apr 16, 2008 at 01:03:22PM -0700, Junio C Hamano wrote:

> > I was only working on making "HEAD" expand to HEAD:<current branch>. I 
> > think that the matching type is only most likely what you want, not 
> > certainly enough to just do it. I'd say that push should suggest it, but 
> > not actually do it automatically, or possibly require -f to do it without 
> > the full name.
> 
> Hmm.  `-f` means "I know there are the ones that do not fast forward but I
> want them updated", which is quite a different thing.  I'd say either we
> should just do it, or we don't, and keep `-f` orthogonal to the ref
> dwimming.

Hmm. I was kind of hoping other people would chime in with opinions on
the dwimmery, but clearly they didn't.

I agree that "-f" is a terrible idea here. Not only is it overloading
what "-f" does, but it's totally unnecessary. If we want to send a
message to the user to retry with different parameters, we can already
say: "try again with refs/heads/$foo".

The "refs/heads/" dwimmery makes sense to me, because:

  1. it changes a behavior which is currently an error condition, so
     we're not hurting anyone's existing workflow

  2. In my usage, pushing a branch to a tag (or vice versa) is the
     exception, so I don't mind favoring pushing like types to like
     types.

But I recognize that (2) is based on my own workflow, so if people
disagree, I guess it isn't so for everyone.

We should probably at least improve the message. Something like this is
perhaps a bit better, or it could even customize the suggestion based
on the source ref's type (i.e., implement the dwimmery, but don't
surprise anyone by doing it automatically).

-Peff

---
diff --git a/remote.c b/remote.c
index 06ad156..2151829 100644
--- a/remote.c
+++ b/remote.c
@@ -867,9 +867,12 @@ static int match_explicit(struct ref *src, struct ref *dst,
 		if (!memcmp(dst_value, "refs/", 5))
 			matched_dst = make_linked_ref(dst_value, dst_tail);
 		else
-			error("dst refspec %s does not match any "
-			      "existing ref on the remote and does "
-			      "not start with refs/.", dst_value);
+			error("The destination refspec does not match any "
+			      "existing ref on the remote,\n"
+			      "and it does not specify a full refname; "
+			      "did you mean one of:\n"
+			      "    refs/heads/%s\n"
+			      "    refs/tags/%s\n", dst_value, dst_value);
 		break;
 	default:
 		matched_dst = NULL;