Re: Confusing git pull error message

[Jeff King <peff@peff.net>]

On Sat, Sep 12, 2009 at 11:01:45PM +0300, John Tapsell wrote:

>   So anyway, I tried to do a "git pull" and it gives me the misleading error:
> 
> You asked me to pull without telling me which branch you
> want to merge with, and 'branch.master.merge' in
> your configuration file does not tell me either.  Please
> name which branch you want to merge on the command line and
> try again (e.g. 'git pull <repository> <refspec>').
> See git-pull(1) for details on the refspec.
>
> [...]
>
> But the actual problem is that "master" doesn't exist on origin.  So
> basically I _have_ told it what branch.master.remote and
> branch.master.merge etc is, it's just that they don't appear to exist.

Ugh. That is horrible. It's an artifact of the (IMHO) brain-dead way
that pull and fetch interact.

Pull doesn't actually look at the configuration at all. It just calls
fetch, and then fetch writes out a file containing the refs it pulled,
some of which may be marked with a magic "not-for-merge" flag. So we see
that nothing is available for merging and guess that it must not have
been configured. Which is of course wrong in your case; it just didn't
exist.

I think it is enough for git-pull to just check whether the config
exists, and if so, guess that the ref was simply not fetched. IOW,
this:

-- >8 --
Subject: [PATCH] pull: make "nothing to merge" error message more accurate

When pull sees that no branches are available for merge and
that we have a current branch, it assumes the problem is
that we had no branch.*.merge configuration. But it may also
be the case that we simply didn't pull the configured ref
(probably because it doesn't exist). Let's distinguish those
two cases.

Signed-off-by: Jeff King <peff@peff.net>
---
 git-pull.sh |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/git-pull.sh b/git-pull.sh
index 0bbd5bf..4ddd537 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -89,6 +89,9 @@ error_on_no_merge_candidates () {
 	done
 
 	curr_branch=${curr_branch#refs/heads/}
+	upstream=`git config "branch.$curr_branch.merge" ||
+		  git config "branch.$curr_branch.rebase"`
+	upstream_short=`echo "$upstream" | sed "s|refs/heads/||"`
 
 	if [ -z "$curr_branch" ]; then
 		echo "You are not currently on a branch, so I cannot use any"
@@ -96,7 +99,7 @@ error_on_no_merge_candidates () {
 		echo "Please specify which branch you want to merge on the command"
 		echo "line and try again (e.g. 'git pull <repository> <refspec>')."
 		echo "See git-pull(1) for details."
-	else
+	elif [ -z "$upstream" ]; then
 		echo "You asked me to pull without telling me which branch you"
 		echo "want to merge with, and 'branch.${curr_branch}.merge' in"
 		echo "your configuration file does not tell me either.	Please"
@@ -114,6 +117,10 @@ error_on_no_merge_candidates () {
 		echo "    remote.<nickname>.fetch = <refspec>"
 		echo
 		echo "See git-config(1) for details."
+	else
+		echo "Your configuration specified for us to pull the ref"
+		echo "'$upstream_short', but we were unable to fetch it from"
+		echo "the remote."
 	fi
 	exit 1
 }
-- 
1.6.5.rc0.201.g76b4d.dirty