pack-objects: allow --shallow and --path-walk

There does not appear to be anything particularly incompatible about the
--shallow and --path-walk options of 'git pack-objects'. If shallow
commits are to be handled differently, then it is by the revision walk
that defines the commit set and which are interesting or uninteresting.

However, before the previous change, a trivial removal of the warning
would cause a failure in t5500-fetch-pack.sh when
GIT_TEST_PACK_PATH_WALK is enabled. The shallow fetch would provide more
objects than we desired, due to some incorrect behavior of the path-walk
API, especially around walking uninteresting objects.

The recently-added tests in t5538-push-shallow.sh help to confirm this
behavior is working with the --path-walk option if
GIT_TEST_PACK_PATH_WALK is enabled. These tests passed previously due to
the --path-walk feature being disabled in the presence of a shallow
clone.

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

Author: derrickstolee

builtin/pack-objects.c

@@ -209,6 +209,7 @@ static int keep_unreachable, unpack_unreachable, include_tag;
 static timestamp_t unpack_unreachable_expiration;
 static int pack_loose_unreachable;
 static int cruft;
+static int shallow = 0;
 static timestamp_t cruft_expiration;
 static int local;
 static int have_non_local_packs;
@@ -4486,6 +4487,7 @@ static void get_object_list_path_walk(struct rev_info *revs)
 	 * base objects.
 	 */
 	info.prune_all_uninteresting = sparse;
+	info.edge_aggressive = shallow;
 
 	if (walk_objects_by_path(&info))
 		die(_("failed to pack objects via path-walk"));
@@ -4687,7 +4689,6 @@ int cmd_pack_objects(int argc,
 		     struct repository *repo UNUSED)
 {
 	int use_internal_rev_list = 0;
-	int shallow = 0;
 	int all_progress_implied = 0;
 	struct strvec rp = STRVEC_INIT;
 	int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
@@ -4875,10 +4876,6 @@ int cmd_pack_objects(int argc,
 		warning(_("cannot use delta islands with --path-walk"));
 		path_walk = 0;
 	}
-	if (path_walk && shallow) {
-		warning(_("cannot use --shallow with --path-walk"));
-		path_walk = 0;
-	}
 	if (path_walk) {
 		strvec_push(&rp, "--boundary");
 		 /*