merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 38 insertions, 9 deletions

diff --git a/third_party/git/serve.c b/third_party/git/serve.c
index 317256c1a4..f6341206c4 100644
--- a/third_party/git/serve.c
+++ b/third_party/git/serve.c
@@ -3,7 +3,7 @@
 #include "config.h"
 #include "pkt-line.h"
 #include "version.h"
-#include "argv-array.h"
+#include "strvec.h"
 #include "ls-refs.h"
 #include "serve.h"
 #include "upload-pack.h"
@@ -22,6 +22,14 @@ static int agent_advertise(struct repository *r,
 	return 1;
 }
 
+static int object_format_advertise(struct repository *r,
+				   struct strbuf *value)
+{
+	if (value)
+		strbuf_addstr(value, r->hash_algo->name);
+	return 1;
+}
+
 struct protocol_capability {
 	/*
 	 * The name of the capability.  The server uses this name when
@@ -48,7 +56,7 @@ struct protocol_capability {
 	 * This field should be NULL for capabilities which are not commands.
 	 */
 	int (*command)(struct repository *r,
-		       struct argv_array *keys,
+		       struct strvec *keys,
 		       struct packet_reader *request);
 };
 
@@ -57,6 +65,7 @@ static struct protocol_capability capabilities[] = {
 	{ "ls-refs", always_advertise, ls_refs },
 	{ "fetch", upload_pack_advertise, upload_pack_v2 },
 	{ "server-option", always_advertise, NULL },
+	{ "object-format", object_format_advertise, NULL },
 };
 
 static void advertise_capabilities(void)
@@ -133,13 +142,13 @@ static int is_command(const char *key, struct protocol_capability **command)
 	return 0;
 }
 
-int has_capability(const struct argv_array *keys, const char *capability,
+int has_capability(const struct strvec *keys, const char *capability,
 		   const char **value)
 {
 	int i;
-	for (i = 0; i < keys->argc; i++) {
+	for (i = 0; i < keys->nr; i++) {
 		const char *out;
-		if (skip_prefix(keys->argv[i], capability, &out) &&
+		if (skip_prefix(keys->v[i], capability, &out) &&
 		    (!*out || *out == '=')) {
 			if (value) {
 				if (*out == '=')
@@ -153,6 +162,22 @@ int has_capability(const struct argv_array *keys, const char *capability,
 	return 0;
 }
 
+static void check_algorithm(struct repository *r, struct strvec *keys)
+{
+	int client = GIT_HASH_SHA1, server = hash_algo_by_ptr(r->hash_algo);
+	const char *algo_name;
+
+	if (has_capability(keys, "object-format", &algo_name)) {
+		client = hash_algo_by_name(algo_name);
+		if (client == GIT_HASH_UNKNOWN)
+			die("unknown object format '%s'", algo_name);
+	}
+
+	if (client != server)
+		die("mismatched object format: server %s; client %s\n",
+		    r->hash_algo->name, hash_algos[client].name);
+}
+
 enum request_state {
 	PROCESS_REQUEST_KEYS,
 	PROCESS_REQUEST_DONE,
@@ -162,7 +187,7 @@ static int process_request(void)
 {
 	enum request_state state = PROCESS_REQUEST_KEYS;
 	struct packet_reader reader;
-	struct argv_array keys = ARGV_ARRAY_INIT;
+	struct strvec keys = STRVEC_INIT;
 	struct protocol_capability *command = NULL;
 
 	packet_reader_init(&reader, 0, NULL, 0,
@@ -186,7 +211,7 @@ static int process_request(void)
 			/* collect request; a sequence of keys and values */
 			if (is_command(reader.line, &command) ||
 			    is_valid_capability(reader.line))
-				argv_array_push(&keys, reader.line);
+				strvec_push(&keys, reader.line);
 			else
 				die("unknown capability '%s'", reader.line);
 
@@ -198,7 +223,7 @@ static int process_request(void)
 			 * If no command and no keys were given then the client
 			 * wanted to terminate the connection.
 			 */
-			if (!keys.argc)
+			if (!keys.nr)
 				return 1;
 
 			/*
@@ -217,15 +242,19 @@ static int process_request(void)
 
 			state = PROCESS_REQUEST_DONE;
 			break;
+		case PACKET_READ_RESPONSE_END:
+			BUG("unexpected stateless separator packet");
 		}
 	}
 
 	if (!command)
 		die("no command requested");
 
+	check_algorithm(the_repository, &keys);
+
 	command->command(the_repository, &keys, &reader);
 
-	argv_array_clear(&keys);
+	strvec_clear(&keys);
 	return 0;
 }