Git-prune-script loses blobs referenced from an uncommitted cache.

(updated from the version posted to GIT mailing list).

When a new blob is registered with update-cache, and before the cache
is written as a tree and committed, git-fsck-cache will find the blob
unreachable.  This patch adds a new flag, "--cache" to git-fsck-cache,
with which it keeps such blobs from considered "unreachable".

The git-prune-script is updated to use this new flag.  At the same time
it adds .git/refs/*/* to the set of default locations to look for heads,
which should be consistent with expectations from Cogito users.

Without this fix, "diff-cache -p --cached" after git-prune-script has
pruned the blob object will fail mysteriously and git-write-tree would
also fail.

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

1 files changed, 24 insertions, 4 deletions

diff --git a/fsck-cache.c b/fsck-cache.c
index fb0d82f33..5db07e0f6 100644
--- a/fsck-cache.c
+++ b/fsck-cache.c
@@ -12,6 +12,7 @@
 static int show_root = 0;
 static int show_tags = 0;
 static int show_unreachable = 0;
+static int keep_cache_objects = 0; 
 static unsigned char head_sha1[20];
 
 static void check_connectivity(void)
@@ -275,8 +276,12 @@ int main(int argc, char **argv)
 			show_root = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--cache")) {
+			keep_cache_objects = 1;
+			continue;
+		}
 		if (*arg == '-')
-			usage("fsck-cache [--tags] [[--unreachable] <head-sha1>*]");
+			usage("fsck-cache [--tags] [[--unreachable] [--cache] <head-sha1>*]");
 	}
 
 	sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
@@ -311,12 +316,27 @@ int main(int argc, char **argv)
 		error("expected sha1, got %s", arg);
 	}
 
-	if (!heads) {
+	if (keep_cache_objects) {
+		int i;
+		read_cache();
+		for (i = 0; i < active_nr; i++) {
+			struct blob *blob = lookup_blob(active_cache[i]->sha1);
+			struct object *obj;
+			if (!blob)
+				continue;
+			obj = &blob->object;
+			obj->used = 1;
+			mark_reachable(obj, REACHABLE);
+		}
+	}
+
+	if (!heads && !keep_cache_objects) {
 		if (show_unreachable) {
-			fprintf(stderr, "unable to do reachability without a head\n");
+			fprintf(stderr, "unable to do reachability without a head nor --cache\n");
 			show_unreachable = 0; 
 		}
-		fprintf(stderr, "expect dangling commits - potential heads - due to lack of head information\n");
+		if (!heads)
+			fprintf(stderr, "expect dangling commits - potential heads - due to lack of head information\n");
 	}
 
 	check_connectivity();