git-reset: refuse to do hard reset in a bare repository

It makes no sense since there is no working tree. A soft
reset should be fine, though.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin-reset.c

@@ -244,6 +244,9 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	if (reset_type == NONE)
 		reset_type = MIXED; /* by default */
 
+	if (reset_type == HARD && is_bare_repository())
+		die("hard reset makes no sense in a bare repository");
+
 	/* Soft reset does not touch the index file nor the working tree
 	 * at all, but requires them in a good order.  Other resets reset
 	 * the index file to the tree object we are switching to. */

t/t7103-reset-bare.sh

+#!/bin/sh
+
+test_description='git-reset in a bare repository'
+. ./test-lib.sh
+
+test_expect_success 'setup non-bare' '
+	echo one >file &&
+	git add file &&
+	git commit -m one &&
+	echo two >file &&
+	git commit -a -m two
+'
+
+test_expect_success 'setup bare' '
+	git clone --bare . bare.git &&
+	cd bare.git
+'
+
+test_expect_success 'hard reset is not allowed' '
+	! git reset --hard HEAD^
+'
+
+test_expect_success 'soft reset is allowed' '
+	git reset --soft HEAD^ &&
+	test "`git show --pretty=format:%s | head -n 1`" = "one"
+'
+
+test_done