smart-http: support shallow fetch/clone

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/gitremote-helpers.txt

@@ -437,6 +437,13 @@ set by Git if the remote helper has the 'option' capability.
 'option check-connectivity' \{'true'|'false'\}::
 	Request the helper to check connectivity of a clone.
 
+'option cloning \{'true'|'false'\}::
+	Notify the helper this is a clone request (i.e. the current
+	repository is guaranteed empty).
+
+'option update-shallow \{'true'|'false'\}::
+	Allow to extend .git/shallow if the new refs require it.
+
 SEE ALSO
 --------
 linkgit:git-remote[1]

builtin/fetch-pack.c

@@ -3,6 +3,7 @@
 #include "fetch-pack.h"
 #include "remote.h"
 #include "connect.h"
+#include "sha1-array.h"
 
 static const char fetch_pack_usage[] =
 "git fetch-pack [--all] [--stdin] [--quiet|-q] [--keep|-k] [--thin] "
@@ -46,6 +47,7 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 	char **pack_lockfile_ptr = NULL;
 	struct child_process *conn;
 	struct fetch_pack_args args;
+	struct sha1_array shallow = SHA1_ARRAY_INIT;
 
 	packet_trace_identity("fetch-pack");
 
@@ -113,6 +115,14 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 			args.check_self_contained_and_connected = 1;
 			continue;
 		}
+		if (!strcmp("--cloning", arg)) {
+			args.cloning = 1;
+			continue;
+		}
+		if (!strcmp("--update-shallow", arg)) {
+			args.update_shallow = 1;
+			continue;
+		}
 		usage(fetch_pack_usage);
 	}
 
@@ -157,10 +167,10 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 				   args.verbose ? CONNECT_VERBOSE : 0);
 	}
 
-	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL, NULL);
+	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL, &shallow);
 
-	ref = fetch_pack(&args, fd, conn, ref, dest,
-			 sought, nr_sought, NULL, pack_lockfile_ptr);
+	ref = fetch_pack(&args, fd, conn, ref, dest, sought, nr_sought,
+			 &shallow, pack_lockfile_ptr);
 	if (pack_lockfile) {
 		printf("lock %s\n", pack_lockfile);
 		fflush(stdout);

remote-curl.c

@@ -10,6 +10,7 @@
 #include "sideband.h"
 #include "argv-array.h"
 #include "credential.h"
+#include "sha1-array.h"
 
 static struct remote *remote;
 /* always ends with a trailing slash */
@@ -20,6 +21,8 @@ struct options {
 	unsigned long depth;
 	unsigned progress : 1,
 		check_self_contained_and_connected : 1,
+		cloning : 1,
+		update_shallow : 1,
 		followtags : 1,
 		dry_run : 1,
 		thin : 1;
@@ -87,8 +90,23 @@ static int set_option(const char *name, const char *value)
 		string_list_append(&cas_options, val.buf);
 		strbuf_release(&val);
 		return 0;
-	}
-	else {
+	} else if (!strcmp(name, "cloning")) {
+		if (!strcmp(value, "true"))
+			options.cloning = 1;
+		else if (!strcmp(value, "false"))
+			options.cloning = 0;
+		else
+			return -1;
+		return 0;
+	} else if (!strcmp(name, "update-shallow")) {
+		if (!strcmp(value, "true"))
+			options.update_shallow = 1;
+		else if (!strcmp(value, "false"))
+			options.update_shallow = 0;
+		else
+			return -1;
+		return 0;
+	} else {
 		return 1 /* unsupported */;
 	}
 }
@@ -99,6 +117,7 @@ struct discovery {
 	char *buf;
 	size_t len;
 	struct ref *refs;
+	struct sha1_array shallow;
 	unsigned proto_git : 1;
 };
 static struct discovery *last_discovery;
@@ -107,7 +126,7 @@ static struct ref *parse_git_refs(struct discovery *heads, int for_push)
 {
 	struct ref *list = NULL;
 	get_remote_heads(-1, heads->buf, heads->len, &list,
-			 for_push ? REF_NORMAL : 0, NULL, NULL);
+			 for_push ? REF_NORMAL : 0, NULL, &heads->shallow);
 	return list;
 }
 
@@ -168,6 +187,7 @@ static void free_discovery(struct discovery *d)
 	if (d) {
 		if (d == last_discovery)
 			last_discovery = NULL;
+		free(d->shallow.sha1);
 		free(d->buf_alloc);
 		free_refs(d->refs);
 		free(d);
@@ -688,7 +708,7 @@ static int fetch_git(struct discovery *heads,
 	struct strbuf preamble = STRBUF_INIT;
 	char *depth_arg = NULL;
 	int argc = 0, i, err;
-	const char *argv[16];
+	const char *argv[17];
 
 	argv[argc++] = "fetch-pack";
 	argv[argc++] = "--stateless-rpc";
@@ -704,6 +724,10 @@ static int fetch_git(struct discovery *heads,
 	}
 	if (options.check_self_contained_and_connected)
 		argv[argc++] = "--check-self-contained-and-connected";
+	if (options.cloning)
+		argv[argc++] = "--cloning";
+	if (options.update_shallow)
+		argv[argc++] = "--update-shallow";
 	if (!options.progress)
 		argv[argc++] = "--no-progress";
 	if (options.depth) {

t/t5537-fetch-shallow.sh

@@ -173,4 +173,31 @@ EOF
 	)
 '
 
+if test -n "$NO_CURL" -o -z "$GIT_TEST_HTTPD"; then
+	say 'skipping remaining tests, git built without http support'
+	test_done
+fi
+
+LIB_HTTPD_PORT=${LIB_HTTPD_PORT-'5536'}
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'clone http repository' '
+	git clone --bare --no-local shallow "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+	git clone $HTTPD_URL/smart/repo.git clone &&
+	(
+	cd clone &&
+	git fsck &&
+	git log --format=%s origin/master >actual &&
+	cat <<EOF >expect &&
+6
+5
+4
+3
+EOF
+	test_cmp expect actual
+	)
+'
+
+stop_httpd
 test_done

transport-helper.c

@@ -360,6 +360,12 @@ static int fetch_with_fetch(struct transport *transport,
 	    data->transport_options.check_self_contained_and_connected)
 		set_helper_option(transport, "check-connectivity", "true");
 
+	if (transport->cloning)
+		set_helper_option(transport, "cloning", "true");
+
+	if (data->transport_options.update_shallow)
+		set_helper_option(transport, "update-shallow", "true");
+
 	for (i = 0; i < nr_heads; i++) {
 		const struct ref *posn = to_fetch[i];
 		if (posn->status & REF_STATUS_UPTODATE)

upload-pack.c

@@ -836,8 +836,6 @@ int main(int argc, char **argv)
 
 	if (!enter_repo(dir, strict))
 		die("'%s' does not appear to be a git repository", dir);
-	if (is_repository_shallow() && stateless_rpc)
-		die("attempt to push into a shallow repository");
 
 	git_config(upload_pack_config, NULL);
 	upload_pack();