[PATCH 08/11] bundle: parse filter capability

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <derrickstolee@github.com>

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'.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 bundle.c                      | 17 ++++++++++++++++-
 bundle.h                      |  3 +++
 list-objects-filter-options.c |  2 +-
 list-objects-filter-options.h |  5 +++++
 4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/bundle.c b/bundle.c
index dc56db9a50a..2afced4d991 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 +33,8 @@ 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);
+	free(header->filter);
 }
 
 static int parse_capability(struct bundle_header *header, const char *capability)
@@ -45,6 +47,11 @@ 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)) {
+		CALLOC_ARRAY(header->filter, 1);
+		parse_list_objects_filter(header->filter, arg);
+		return 0;
+	}
 	return error(_("unknown capability '%s'"), capability);
 }
 
@@ -220,6 +227,8 @@ int verify_bundle(struct repository *r,
 	req_nr = revs.pending.nr;
 	setup_revisions(2, argv, &revs, NULL);
 
+	revs.filter = header->filter;
+
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
 
@@ -259,6 +268,12 @@ int verify_bundle(struct repository *r,
 			     r->nr),
 			  r->nr);
 		list_refs(r, 0, NULL);
+
+		if (header->filter) {
+			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."));
diff --git a/bundle.h b/bundle.h
index 06009fe6b1f..eb026153d56 100644
--- a/bundle.h
+++ b/bundle.h
@@ -5,11 +5,14 @@
 #include "cache.h"
 #include "string-list.h"
 
+struct list_objects_filter_options;
+
 struct bundle_header {
 	unsigned version;
 	struct string_list prerequisites;
 	struct string_list references;
 	const struct git_hash_algo *hash_algo;
+	struct list_objects_filter_options *filter;
 };
 
 #define BUNDLE_HEADER_INIT \
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index fd8d59f653a..b9d10770e4f 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -55,7 +55,7 @@ const char *list_object_filter_config_name(enum list_objects_filter_choice c)
  * expand_list_objects_filter_spec() first).  We also "intern" the arg for the
  * convenience of the current command.
  */
-static int gently_parse_list_objects_filter(
+int gently_parse_list_objects_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf)
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index da5b6737e27..347a99c28cf 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -72,6 +72,11 @@ struct list_objects_filter_options {
 /* Normalized command line arguments */
 #define CL_ARG__FILTER "filter"
 
+int gently_parse_list_objects_filter(
+	struct list_objects_filter_options *filter_options,
+	const char *arg,
+	struct strbuf *errbuf);
+
 void list_objects_filter_die_if_populated(
 	struct list_objects_filter_options *filter_options);
 
-- 
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