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authorJunio C Hamano <gitster@pobox.com>2011-11-16 22:04:03 -0800
committerJunio C Hamano <gitster@pobox.com>2011-11-16 22:06:08 -0800
commitf63c79dbc8c5670533557d311ed0e81fcfc9fe3a (patch)
tree23bbcdba48b0eb9efa8212c47ffff5bfb041f42f /builtin/pack-objects.c
parent632052641517de1a965c1f045b97d2eaa541b2e9 (diff)
downloadgit-f63c79dbc8c5670533557d311ed0e81fcfc9fe3a.tar.gz
pack-object: tolerate broken packs that have duplicated objectsjc/maint-pack-object-cycle
When --reuse-delta is in effect (which is the default), and an existing pack in the repository has the same object registered twice (e.g. one copy in a non-delta format and the other copy in a delta against some other object), an attempt to repack the repository can result in a cyclic delta dependency, causing write_one() function to infinitely recurse into itself. Detect such a case and break the loopy dependency by writing out an object that is involved in such a loop in the non-delta format. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/pack-objects.c')
-rw-r--r--builtin/pack-objects.c55
1 files changed, 43 insertions, 12 deletions
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index c6e2d8766b..5ae808b8d9 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -404,25 +404,56 @@ static unsigned long write_object(struct sha1file *f,
return hdrlen + datalen;
}
-static int write_one(struct sha1file *f,
- struct object_entry *e,
- off_t *offset)
+enum write_one_status {
+ WRITE_ONE_SKIP = -1, /* already written */
+ WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
+ WRITE_ONE_WRITTEN = 1, /* normal */
+ WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
+};
+
+static enum write_one_status write_one(struct sha1file *f,
+ struct object_entry *e,
+ off_t *offset)
{
unsigned long size;
+ int recursing;
- /* offset is non zero if object is written already. */
- if (e->idx.offset || e->preferred_base)
- return -1;
+ /*
+ * we set offset to 1 (which is an impossible value) to mark
+ * the fact that this object is involved in "write its base
+ * first before writing a deltified object" recursion.
+ */
+ recursing = (e->idx.offset == 1);
+ if (recursing) {
+ warning("recursive delta detected for object %s",
+ sha1_to_hex(e->idx.sha1));
+ return WRITE_ONE_RECURSIVE;
+ } else if (e->idx.offset || e->preferred_base) {
+ /* offset is non zero if object is written already. */
+ return WRITE_ONE_SKIP;
+ }
/* if we are deltified, write out base object first. */
- if (e->delta && !write_one(f, e->delta, offset))
- return 0;
+ if (e->delta) {
+ e->idx.offset = 1; /* now recurse */
+ switch (write_one(f, e->delta, offset)) {
+ case WRITE_ONE_RECURSIVE:
+ /* we cannot depend on this one */
+ e->delta = NULL;
+ break;
+ default:
+ break;
+ case WRITE_ONE_BREAK:
+ e->idx.offset = recursing;
+ return WRITE_ONE_BREAK;
+ }
+ }
e->idx.offset = *offset;
size = write_object(f, e, *offset);
if (!size) {
- e->idx.offset = 0;
- return 0;
+ e->idx.offset = recursing;
+ return WRITE_ONE_BREAK;
}
written_list[nr_written++] = &e->idx;
@@ -430,7 +461,7 @@ static int write_one(struct sha1file *f,
if (signed_add_overflows(*offset, size))
die("pack too large for current definition of off_t");
*offset += size;
- return 1;
+ return WRITE_ONE_WRITTEN;
}
static void write_pack_file(void)
@@ -468,7 +499,7 @@ static void write_pack_file(void)
offset = sizeof(hdr);
nr_written = 0;
for (; i < nr_objects; i++) {
- if (!write_one(f, objects + i, &offset))
+ if (write_one(f, objects + i, &offset) == WRITE_ONE_BREAK)
break;
display_progress(progress_state, written);
}