Make sure get_sha1 does not accept ambiguous sha1 prefix (again).

The earlier fix incorrectly dropped the code the original had to
ensure the found SHA1 is at least unique within the same pack.
Restore the check.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/sha1_name.c b/sha1_name.c
index 8920de1c45ce0a094fbc0b5ea2ca744ef27c6393..f64755fbceea617c424b9b83999eeaa91bf76af1 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -91,14 +91,23 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
                        last = mid;
                }
                if (first < num) {
-                       unsigned char now[20];
+                       unsigned char now[20], next[20];
                        nth_packed_object_sha1(p, first, now);
                        if (match_sha(len, match, now)) {
-                               if (!found) {
-                                       memcpy(found_sha1, now, 20);
-                                       found++;
+                               if (nth_packed_object_sha1(p, first+1, next) ||
+                                   !match_sha(len, match, next)) {
+                                       /* unique within this pack */
+                                       if (!found) {
+                                               memcpy(found_sha1, now, 20);
+                                               found++;
+                                       }
+                                       else if (memcmp(found_sha1, now, 20)) {
+                                               found = 2;
+                                               break;
+                                       }
                                }
-                               else if (memcmp(found_sha1, now, 20)) {
+                               else {
+                                       /* not even unique within this pack */
                                        found = 2;
                                        break;
                                }
@@ -121,7 +130,7 @@ static int find_unique_short_object(int len, char *canonical,
        if (!has_unpacked && !has_packed)
                return -1;
        if (1 < has_unpacked || 1 < has_packed)
-               return -1;
+               return error("short SHA1 %.*s is ambiguous.", len, canonical);
        if (has_unpacked != has_packed) {
                memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
                return 0;