bundle: parse filter capability

The v3 bundle format has capabilities, allowing newer versions of Git to
create bundles with newer features. Older versions that do not
understand these new capabilities will fail with a helpful warning.

Create a new capability allowing Git to understand that the contained
pack-file is filtered according to some object filter. Typically, this
filter will be "blob:none" for a blobless partial clone.

This change teaches Git to parse this capability, place its value in the
bundle header, and demonstrate this understanding by adding a message to
'git bundle verify'.

Since we will use gently_parse_list_objects_filter() outside of
list-objects-filter-options.c, make it an external method and move its
API documentation to before its declaration.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/bundle.c b/bundle.c
index 7ba60a573d..41e75efab9 100644
--- a/bundle.c
+++ b/bundle.c
@@ -11,7 +11,7 @@
 #include "run-command.h"
 #include "refs.h"
 #include "strvec.h"
-
+#include "list-objects-filter-options.h"
 
 static const char v2_bundle_signature[] = "# v2 git bundle\n";
 static const char v3_bundle_signature[] = "# v3 git bundle\n";
@@ -33,6 +33,7 @@ void bundle_header_release(struct bundle_header *header)
 {
 	string_list_clear(&header->prerequisites, 1);
 	string_list_clear(&header->references, 1);
+	list_objects_filter_release(&header->filter);
 }
 
 static int parse_capability(struct bundle_header *header, const char *capability)
@@ -45,6 +46,10 @@ static int parse_capability(struct bundle_header *header, const char *capability
 		header->hash_algo = &hash_algos[algo];
 		return 0;
 	}
+	if (skip_prefix(capability, "filter=", &arg)) {
+		parse_list_objects_filter(&header->filter, arg);
+		return 0;
+	}
 	return error(_("unknown capability '%s'"), capability);
 }
 
@@ -220,6 +225,8 @@ int verify_bundle(struct repository *r,
 	req_nr = revs.pending.nr;
 	setup_revisions(2, argv, &revs, NULL);
 
+	list_objects_filter_copy(&revs.filter, &header->filter);
+
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
 
@@ -259,6 +266,12 @@ int verify_bundle(struct repository *r,
 			     r->nr),
 			  r->nr);
 		list_refs(r, 0, NULL);
+
+		if (header->filter.choice) {
+			printf_ln("The bundle uses this filter: %s",
+				  list_objects_filter_spec(&header->filter));
+		}
+
 		r = &header->prerequisites;
 		if (!r->nr) {
 			printf_ln(_("The bundle records a complete history."));