get_sha1: teach ":$n:<path>" the same relative path logic

We taught the object name parser to take ":./<path>", ":../<path>", etc.
and understand them to be relative to the current working directory.

Given that ":<path>" is just a short-hand for ":0:<path>" (i.e. "take
stage #0 of that path"), we should allow ":$n:<path>" to interpret them
the same way.

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

2 files changed, 32 insertions, 6 deletions

diff --git a/sha1_name.c b/sha1_name.c
index f918faf5c7..207405688b 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1091,17 +1091,19 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 			return get_sha1_oneline(name + 2, sha1);
 		if (namelen < 3 ||
 		    name[2] != ':' ||
-		    name[1] < '0' || '3' < name[1]) {
+		    name[1] < '0' || '3' < name[1])
 			cp = name + 1;
-			new_path = resolve_relative_path(cp);
-			if (new_path)
-				cp = new_path;
-		}
 		else {
 			stage = name[1] - '0';
 			cp = name + 3;
 		}
-		namelen = strlen(cp);
+		new_path = resolve_relative_path(cp);
+		if (!new_path) {
+			namelen = namelen - (cp - name);
+		} else {
+			cp = new_path;
+			namelen = strlen(cp);
+		}
 
 		strncpy(oc->path, cp,
 			sizeof(oc->path));
diff --git a/t/t1506-rev-parse-diagnosis.sh b/t/t1506-rev-parse-diagnosis.sh
index 18664702b9..9f8adb1f82 100755
--- a/t/t1506-rev-parse-diagnosis.sh
+++ b/t/t1506-rev-parse-diagnosis.sh
@@ -34,6 +34,8 @@ test_expect_success 'correct file objects' '
 test_expect_success 'correct relative file objects (0)' '
 	git rev-parse :file.txt >expected &&
 	git rev-parse :./file.txt >result &&
+	test_cmp expected result &&
+	git rev-parse :0:./file.txt >result &&
 	test_cmp expected result
 '
 
@@ -68,6 +70,28 @@ test_expect_success 'correct relative file objects (4)' '
 	)
 '
 
+test_expect_success 'correct relative file objects (5)' '
+	git rev-parse :subdir/file.txt >expected &&
+	(
+		cd subdir &&
+		git rev-parse :./file.txt >result &&
+		test_cmp ../expected result &&
+		git rev-parse :0:./file.txt >result &&
+		test_cmp ../expected result
+	)
+'
+
+test_expect_success 'correct relative file objects (6)' '
+	git rev-parse :file.txt >expected &&
+	(
+		cd subdir &&
+		git rev-parse :../file.txt >result &&
+		test_cmp ../expected result &&
+		git rev-parse :0:../file.txt >result &&
+		test_cmp ../expected result
+	)
+'
+
 test_expect_success 'incorrect revision id' '
 	test_must_fail git rev-parse foobar:file.txt 2>error &&
 	grep "Invalid object name '"'"'foobar'"'"'." error &&