request-pull: really favor a matching tag

After tagging the tip of "dev" branch with a "for-linus" tag and
pushing both out, running

	$ git request-pull $url $last_release dev

would produce an output asking the 'dev' branch of $url to be
pulled, because that is what the user asked the message to say.

We already detect this situation locally and include the contents of
the tag in the output; if the $url has that tag, favor that tag
(i.e. "for-linus") in the generated message over the branch name the
user gave us (i.e. "dev") from the command line, to make the output
look more consistent.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-request-pull.sh

@@ -57,9 +57,13 @@ headrev=$(git rev-parse --verify "$head"^0) || exit
 merge_base=$(git merge-base $baserev $headrev) ||
 die "fatal: No commits in common between $base and $head"
 
-# $head is the token given from the command line. If a ref with that
-# name exists at the remote and their values match, we should use it.
-# Otherwise find a ref that matches $headrev.
+# $head is the token given from the command line, and $tag_name, if
+# exists, is the tag we are going to show the commit information for.
+# If that tag exists at the remote and it points at the commit, use it.
+# Otherwise, if a branch with the same name as $head exists at the remote
+# and their values match, use that instead.
+#
+# Otherwise find a random ref that matches $headrev.
 find_matching_ref='
 	sub abbr {
 		my $ref = shift;
@@ -70,24 +74,29 @@ find_matching_ref='
 		}
 	}
 
-	my ($exact, $found);
+	my ($tagged, $branch, $found);
 	while (<STDIN>) {
 		my ($sha1, $ref, $deref) = /^(\S+)\s+(\S+?)(\^\{\})?$/;
 		next unless ($sha1 eq $ARGV[1]);
 		$found = abbr($ref);
+		if ($deref && $ref eq "tags/$ARGV[2]") {
+			$tagged = $found;
+			last;
+		}
 		if ($ref =~ m|/\Q$ARGV[0]\E$|) {
 			$exact = $found;
-			last;
 		}
 	}
-	if ($exact) {
+	if ($tagged) {
+		print "$tagged\n";
+	} elsif ($exact) {
 		print "$exact\n";
 	} elsif ($found) {
 		print "$found\n";
 	}
 '
 
-ref=$(git ls-remote "$url" | perl -e "$find_matching_ref" "$head" "$headrev")
+ref=$(git ls-remote "$url" | perl -e "$find_matching_ref" "$head" "$headrev" "$tag_name")
 
 url=$(git ls-remote --get-url "$url")
 
@@ -114,6 +123,12 @@ fi &&
 
 if test -n "$tag_name"
 then
+	if test -z "$ref" || test "$ref" != "tags/$tag_name"
+	then
+		echo >&2 "warn: You locally have $tag_name but it does not (yet)"
+		echo >&2 "warn: appear to be at $url"
+		echo >&2 "warn: Do you want to push it there, perhaps?"
+	fi
 	git cat-file tag "$tag_name" |
 	sed -n -e '1,/^$/d' -e '/^-----BEGIN PGP /q' -e p
 	echo