From 477673d6f39b4829baa98ad88d6b65b35b79fd0f Mon Sep 17 00:00:00 2001 From: Jonathan Tan Date: Tue, 4 May 2021 14:16:02 -0700 Subject: [PATCH] send-pack: support push negotiation Teach Git the push.negotiate config variable. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano --- Documentation/config/push.txt | 7 ++++ send-pack.c | 61 ++++++++++++++++++++++++++++++++--- t/t5516-fetch-push.sh | 35 ++++++++++++++++++++ 3 files changed, 99 insertions(+), 4 deletions(-) diff --git a/Documentation/config/push.txt b/Documentation/config/push.txt index 21b256e0a4..f2667b2689 100644 --- a/Documentation/config/push.txt +++ b/Documentation/config/push.txt @@ -120,3 +120,10 @@ push.useForceIfIncludes:: `--force-if-includes` as an option to linkgit:git-push[1] in the command line. Adding `--no-force-if-includes` at the time of push overrides this configuration setting. + +push.negotiate:: + If set to "true", attempt to reduce the size of the packfile + sent by rounds of negotiation in which the client and the + server attempt to find commits in common. If "false", Git will + rely solely on the server's ref advertisement to find commits + in common. diff --git a/send-pack.c b/send-pack.c index 5f215b13c7..9cb9f71650 100644 --- a/send-pack.c +++ b/send-pack.c @@ -56,7 +56,9 @@ static void feed_object(const struct object_id *oid, FILE *fh, int negative) /* * Make a pack stream and spit it out into file descriptor fd */ -static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struct send_pack_args *args) +static int pack_objects(int fd, struct ref *refs, struct oid_array *advertised, + struct oid_array *negotiated, + struct send_pack_args *args) { /* * The child becomes pack-objects --revs; we feed @@ -94,8 +96,10 @@ static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struc * parameters by writing to the pipe. */ po_in = xfdopen(po.in, "w"); - for (i = 0; i < extra->nr; i++) - feed_object(&extra->oid[i], po_in, 1); + for (i = 0; i < advertised->nr; i++) + feed_object(&advertised->oid[i], po_in, 1); + for (i = 0; i < negotiated->nr; i++) + feed_object(&negotiated->oid[i], po_in, 1); while (refs) { if (!is_null_oid(&refs->old_oid)) @@ -409,11 +413,55 @@ static void reject_invalid_nonce(const char *nonce, int len) } } +static void get_commons_through_negotiation(const char *url, + const struct ref *remote_refs, + struct oid_array *commons) +{ + struct child_process child = CHILD_PROCESS_INIT; + const struct ref *ref; + int len = the_hash_algo->hexsz + 1; /* hash + NL */ + + child.git_cmd = 1; + child.no_stdin = 1; + child.out = -1; + strvec_pushl(&child.args, "fetch", "--negotiate-only", NULL); + for (ref = remote_refs; ref; ref = ref->next) + strvec_pushf(&child.args, "--negotiation-tip=%s", oid_to_hex(&ref->new_oid)); + strvec_push(&child.args, url); + + if (start_command(&child)) + die(_("send-pack: unable to fork off fetch subprocess")); + + do { + char hex_hash[GIT_MAX_HEXSZ + 1]; + int read_len = read_in_full(child.out, hex_hash, len); + struct object_id oid; + const char *end; + + if (!read_len) + break; + if (read_len != len) + die("invalid length read %d", read_len); + if (parse_oid_hex(hex_hash, &oid, &end) || *end != '\n') + die("invalid hash"); + oid_array_append(commons, &oid); + } while (1); + + if (finish_command(&child)) { + /* + * The information that push negotiation provides is useful but + * not mandatory. + */ + warning(_("push negotiation failed; proceeding anyway with push")); + } +} + int send_pack(struct send_pack_args *args, int fd[], struct child_process *conn, struct ref *remote_refs, struct oid_array *extra_have) { + struct oid_array commons = OID_ARRAY_INIT; int in = fd[0]; int out = fd[1]; struct strbuf req_buf = STRBUF_INIT; @@ -426,6 +474,7 @@ int send_pack(struct send_pack_args *args, int quiet_supported = 0; int agent_supported = 0; int advertise_sid = 0; + int push_negotiate = 0; int use_atomic = 0; int atomic_supported = 0; int use_push_options = 0; @@ -437,6 +486,10 @@ int send_pack(struct send_pack_args *args, const char *push_cert_nonce = NULL; struct packet_reader reader; + git_config_get_bool("push.negotiate", &push_negotiate); + if (push_negotiate) + get_commons_through_negotiation(args->url, remote_refs, &commons); + git_config_get_bool("transfer.advertisesid", &advertise_sid); /* Does the other end support the reporting? */ @@ -625,7 +678,7 @@ int send_pack(struct send_pack_args *args, PACKET_READ_DIE_ON_ERR_PACKET); if (need_pack_data && cmds_sent) { - if (pack_objects(out, remote_refs, extra_have, args) < 0) { + if (pack_objects(out, remote_refs, extra_have, &commons, args) < 0) { if (args->stateless_rpc) close(out); if (git_connection_is_socket(conn)) diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh index f11742ed59..0916f76302 100755 --- a/t/t5516-fetch-push.sh +++ b/t/t5516-fetch-push.sh @@ -191,6 +191,41 @@ test_expect_success 'fetch with pushInsteadOf (should not rewrite)' ' ) ' +grep_wrote () { + object_count=$1 + file_name=$2 + grep 'write_pack_file/wrote.*"value":"'$1'"' $2 +} + +test_expect_success 'push with negotiation' ' + # Without negotiation + mk_empty testrepo && + git push testrepo $the_first_commit:refs/remotes/origin/first_commit && + git -C testrepo config receive.hideRefs refs/remotes/origin/first_commit && + echo now pushing without negotiation && + GIT_TRACE2_EVENT="$(pwd)/event" git -c protocol.version=2 push testrepo refs/heads/main:refs/remotes/origin/main && + grep_wrote 5 event && # 2 commits, 2 trees, 1 blob + + # Same commands, but with negotiation + rm event && + mk_empty testrepo && + git push testrepo $the_first_commit:refs/remotes/origin/first_commit && + git -C testrepo config receive.hideRefs refs/remotes/origin/first_commit && + GIT_TRACE2_EVENT="$(pwd)/event" git -c protocol.version=2 -c push.negotiate=1 push testrepo refs/heads/main:refs/remotes/origin/main && + grep_wrote 2 event # 1 commit, 1 tree +' + +test_expect_success 'push with negotiation proceeds anyway even if negotiation fails' ' + rm event && + mk_empty testrepo && + git push testrepo $the_first_commit:refs/remotes/origin/first_commit && + git -C testrepo config receive.hideRefs refs/remotes/origin/first_commit && + GIT_TEST_PROTOCOL_VERSION=0 GIT_TRACE2_EVENT="$(pwd)/event" \ + git -c push.negotiate=1 push testrepo refs/heads/main:refs/remotes/origin/main 2>err && + grep_wrote 5 event && # 2 commits, 2 trees, 1 blob + test_i18ngrep "push negotiation failed" err +' + test_expect_success 'push without wildcard' ' mk_empty testrepo &&