[PATCH v3] ls-remote: fall-back to default remotes when no remote specified

[Tay Ray Chuan <rctay89@gmail.com>]

Instead of breaking execution when no remote (as specified in the
variable dest) is specified when git-ls-remote is invoked, continue on
and let remote_get() handle it.

This way, we are able to use the default remotes (eg. "origin",
branch.<name>.remote), as git-fetch, git-push, and other users of
remote_get(), do.

If no suitable remote is found, exit with a message describing the
issue, instead of just the usage text, as we do previously.

Add several tests to check that git-ls-remote handles the
no-remote-specified situation.

Also add a test that "git ls-remote <pattern>" does not work; we are
unable to guess the remote in that situation, as are git-fetch and
git-push.

In that test, we are testing for messages coming from two separate
processes, but we should be OK, because the second message is triggered
by closing the fd which must happen after the first message is printed.
(analysis by Jeff King.)

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
---
 builtin/ls-remote.c  |   11 ++++++---
 t/t5512-ls-remote.sh |   58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 4 deletions(-)

diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 70f5622..6c738c9 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -4,7 +4,8 @@
 #include "remote.h"
 
 static const char ls_remote_usage[] =
-"git ls-remote [--heads] [--tags]  [-u <exec> | --upload-pack <exec>] <repository> <refs>...";
+       "git ls-remote [--heads] [--tags]  [-u <exec> | --upload-pack <exec>]\n"
+"                     [<repository> [<refs>...]]";
 
 /*
  * Is there one among the list of patterns that match the tail part
@@ -73,9 +74,6 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 		break;
 	}
 
-	if (!dest)
-		usage(ls_remote_usage);
-
 	if (argv[i]) {
 		int j;
 		pattern = xcalloc(sizeof(const char *), argc - i + 1);
@@ -87,6 +85,11 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 		}
 	}
 	remote = remote_get(dest);
+	if (!remote) {
+		if (dest)
+			die("bad repository '%s'", dest);
+		die("No remote configured to list refs from.");
+	}
 	if (!remote->url_nr)
 		die("remote %s has no configured URL", dest);
 	transport = transport_get(remote, NULL);
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index 1dd8eed..3cf1b3d 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -49,4 +49,62 @@ test_expect_success 'ls-remote self' '
 
 '
 
+test_expect_success 'dies when no remote specified and no default remotes found' '
+
+	test_must_fail git ls-remote
+
+'
+
+test_expect_success 'use "origin" when no remote specified' '
+
+	git remote add origin "$(pwd)/.git" &&
+	git ls-remote >actual &&
+	test_cmp expected.all actual
+
+'
+
+test_expect_success 'use branch.<name>.remote if possible' '
+
+	#
+	# Test that we are indeed using branch.<name>.remote, not "origin", even
+	# though the "origin" remote has been set.
+	#
+
+	# setup a new remote to differentiate from "origin"
+	git clone . other.git &&
+	(
+		cd other.git &&
+		echo "$(git rev-parse HEAD)	HEAD"
+		git show-ref	| sed -e "s/ /	/"
+	) >exp &&
+
+	git remote add other other.git &&
+	git config branch.master.remote other &&
+
+	git ls-remote >actual &&
+	test_cmp exp actual
+
+'
+
+cat >exp <<EOF
+fatal: 'refs*master' does not appear to be a git repository
+fatal: The remote end hung up unexpectedly
+EOF
+test_expect_success 'confuses pattern as remote when no remote specified' '
+	#
+	# Do not expect "git ls-remote <pattern>" to work; ls-remote, correctly,
+	# confuses <pattern> for <remote>. Although ugly, this behaviour is akin
+	# to the confusion of refspecs for remotes by git-fetch and git-push,
+	# eg:
+	#
+	#   $ git fetch branch
+	#
+
+	# We could just as easily have used "master"; the "*" emphasizes its
+	# role as a pattern.
+	test_must_fail git ls-remote refs*master >actual 2>&1 &&
+	test_cmp exp actual
+
+'
+
 test_done
-- 
1.7.0.97.g1372c