[v3,15/44] builtin/receive-pack: detect when the server doesn't support our hash

Commit Message

brian m. carlson June 19, 2020, 5:55 p.m. UTC

Detect when the server doesn't support our hash algorithm and abort.

Signed-off-by: brian m. carlson <[e-mail]>
---
 builtin/receive-pack.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 4ffa501dce..d43663bb0a 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1625,6 +1625,8 @@  static struct command *read_head_info(struct packet_reader *reader,
 		linelen = strlen(reader->line);
 		if (linelen < reader->pktlen) {
 			const char *feature_list = reader->line + linelen + 1;
+			const char *hash = NULL;
+			int len = 0;
 			if (parse_feature_request(feature_list, "report-status"))
 				report_status = 1;
 			if (parse_feature_request(feature_list, "side-band-64k"))
@@ -1637,6 +1639,13 @@  static struct command *read_head_info(struct packet_reader *reader,
 			if (advertise_push_options
 			    && parse_feature_request(feature_list, "push-options"))
 				use_push_options = 1;
+			hash = parse_feature_value(feature_list, "object-format", &len, NULL);
+			if (!hash) {
+				hash = hash_algos[GIT_HASH_SHA1].name;
+				len = strlen(hash);
+			}
+			if (xstrncmpz(the_hash_algo->name, hash, len))
+				die("error: unsupported object format '%s'", hash);
 		}
 
 		if (!strcmp(reader->line, "push-cert")) {