[PATCH] Adjust fsck-cache to packed GIT and alternate object pool.

The fsck-cache complains if objects referred to by files in .git/refs/
or objects stored in files under .git/objects/??/ are not found as
stand-alone SHA1 files (i.e.  found in alternate object pools
GIT_ALTERNATE_OBJECT_DIRECTORIES or packed archives stored under
.git/objects/pack).

Although this is a good semantics to maintain consistency of a single
.git/objects directory as a self contained set of objects, it sometimes
is useful to consider it is OK as long as these "outside" objects are
available.

This commit introduces a new flag, --standalone, to git-fsck-cache.
When it is not specified, connectivity checks and .git/refs pointer
checks are taught that it is OK when expected objects do not exist under
.git/objects/?? hierarchy but are available from an packed archive or in
an alternate object pool.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fsck-cache.c

@@ -12,6 +12,7 @@
 static int show_root = 0;
 static int show_tags = 0;
 static int show_unreachable = 0;
+static int standalone = 0;
 static int keep_cache_objects = 0; 
 static unsigned char head_sha1[20];
 
@@ -25,13 +26,17 @@ static void check_connectivity(void)
 		struct object_list *refs;
 
 		if (!obj->parsed) {
-			printf("missing %s %s\n",
-			       obj->type, sha1_to_hex(obj->sha1));
+			if (!standalone && has_sha1_file(obj->sha1))
+				; /* it is in pack */
+			else
+				printf("missing %s %s\n",
+				       obj->type, sha1_to_hex(obj->sha1));
 			continue;
 		}
 
 		for (refs = obj->refs; refs; refs = refs->next) {
-			if (refs->item->parsed)
+			if (refs->item->parsed ||
+			    (!standalone && has_sha1_file(refs->item->sha1)))
 				continue;
 			printf("broken link from %7s %s\n",
 			       obj->type, sha1_to_hex(obj->sha1));
@@ -315,8 +320,11 @@ static int read_sha1_reference(const char *path)
 		return -1;
 
 	obj = lookup_object(sha1);
-	if (!obj)
+	if (!obj) {
+		if (!standalone && has_sha1_file(sha1))
+			return 0; /* it is in pack */
 		return error("%s: invalid sha1 pointer %.40s", path, hexname);
+	}
 
 	obj->used = 1;
 	mark_reachable(obj, REACHABLE);
@@ -390,6 +398,10 @@ int main(int argc, char **argv)
 			keep_cache_objects = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--standalone")) {
+			standalone = 1;
+			continue;
+		}
 		if (*arg == '-')
 			usage("git-fsck-cache [--tags] [[--unreachable] [--cache] <head-sha1>*]");
 	}