builtin/fetch-pack: add --refetch option

Add a refetch option to fetch-pack to force a full fetch. Use when
applying a new partial clone filter to refetch all matching objects.

Signed-off-by: Robert Coup <robert@coup.net.nz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-fetch-pack.txt

@@ -101,6 +101,10 @@ be in a separate packet, and the list must end with a flush packet.
 	current shallow boundary instead of from the tip of each
 	remote branch history.
 
+--refetch::
+	Skips negotiating commits with the server in order to fetch all matching
+	objects. Use to reapply a new partial clone blob/tree filter.
+
 --no-progress::
 	Do not show the progress.
 

builtin/fetch-pack.c

@@ -153,6 +153,10 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 			args.from_promisor = 1;
 			continue;
 		}
+		if (!strcmp("--refetch", arg)) {
+			args.refetch = 1;
+			continue;
+		}
 		if (skip_prefix(arg, ("--" CL_ARG__FILTER "="), &arg)) {
 			parse_list_objects_filter(&args.filter_options, arg);
 			continue;

remote-curl.c

@@ -43,6 +43,7 @@ struct options {
 		/* see documentation of corresponding flag in fetch-pack.h */
 		from_promisor : 1,
 
+		refetch : 1,
 		atomic : 1,
 		object_format : 1,
 		force_if_includes : 1;
@@ -198,6 +199,9 @@ static int set_option(const char *name, const char *value)
 	} else if (!strcmp(name, "from-promisor")) {
 		options.from_promisor = 1;
 		return 0;
+	} else if (!strcmp(name, "refetch")) {
+		options.refetch = 1;
+		return 0;
 	} else if (!strcmp(name, "filter")) {
 		options.filter = xstrdup(value);
 		return 0;
@@ -1182,6 +1186,8 @@ static int fetch_git(struct discovery *heads,
 		strvec_push(&args, "--deepen-relative");
 	if (options.from_promisor)
 		strvec_push(&args, "--from-promisor");
+	if (options.refetch)
+		strvec_push(&args, "--refetch");
 	if (options.filter)
 		strvec_pushf(&args, "--filter=%s", options.filter);
 	strvec_push(&args, url.buf);