pack-objects: consider packs in multi-pack-index

When running 'git pack-objects --local', we want to avoid packing
objects that are in an alternate. Currently, we check for these
objects using the packed_git_mru list, which excludes the pack-files
covered by a multi-pack-index.

Add a new iteration over the multi-pack-indexes to find these
copies and mark them as unwanted.

Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

builtin/pack-objects.c

@@ -31,6 +31,7 @@
 #include "packfile.h"
 #include "object-store.h"
 #include "dir.h"
+#include "midx.h"
 
 #define IN_PACK(obj) oe_in_pack(&to_pack, obj)
 #define SIZE(obj) oe_size(&to_pack, obj)
@@ -1040,6 +1041,7 @@ static int want_object_in_pack(const struct object_id *oid,
 {
 	int want;
 	struct list_head *pos;
+	struct multi_pack_index *m;
 
 	if (!exclude && local && has_loose_object_nonlocal(oid))
 		return 0;
@@ -1054,6 +1056,32 @@ static int want_object_in_pack(const struct object_id *oid,
 		if (want != -1)
 			return want;
 	}
+
+	for (m = get_multi_pack_index(the_repository); m; m = m->next) {
+		struct pack_entry e;
+		if (fill_midx_entry(oid, &e, m)) {
+			struct packed_git *p = e.p;
+			off_t offset;
+
+			if (p == *found_pack)
+				offset = *found_offset;
+			else
+				offset = find_pack_entry_one(oid->hash, p);
+
+			if (offset) {
+				if (!*found_pack) {
+					if (!is_pack_valid(p))
+						continue;
+					*found_offset = offset;
+					*found_pack = p;
+				}
+				want = want_found_object(exclude, p);
+				if (want != -1)
+					return want;
+			}
+		}
+	}
+
 	list_for_each(pos, get_packed_git_mru(the_repository)) {
 		struct packed_git *p = list_entry(pos, struct packed_git, mru);
 		off_t offset;

t/t5319-multi-pack-index.sh

@@ -176,7 +176,13 @@ test_expect_success 'multi-pack-index and alternates' '
 compare_results_with_midx "with alternate (local midx)"
 
 test_expect_success 'multi-pack-index in an alternate' '
-	mv .git/objects/pack/* alt.git/objects/pack
+	mv .git/objects/pack/* alt.git/objects/pack &&
+	test_commit add_local_objects &&
+	git repack --local &&
+	git multi-pack-index write &&
+	midx_read_expect 1 3 4 $objdir &&
+	git reset --hard HEAD~1 &&
+	rm -f .git/objects/pack/*
 '
 
 compare_results_with_midx "with alternate (remote midx)"