[PATCH 2/2] fetch-pack: in protocol v2, reset in_vain upon ACK

From

JTJonathan Tan <jonathantanmy@google.com>

Date

Apr 25, 2020, 00:56 UTC

Message-ID

<8499d5268e49b6b823b0b9312d77e41e311d9a75.1587775989.git.jonathantanmy@google.com>

In-Reply-To

<cover.1587775989.git.jonathantanmy@google.com>

Therefore, reset the in_vain counter upon every ACK.

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 fetch-pack.c          |  1 +
 t/t5500-fetch-pack.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/fetch-pack.c b/fetch-pack.c
index 7d15c7af81..8551c07ed9 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1287,6 +1287,7 @@ static int process_acks(struct fetch_negotiator *negotiator,
 
 		if (skip_prefix(reader->line, "ACK ", &arg)) {
 			struct object_id oid;
+			received_ack = 1;
 			if (!get_oid_hex(arg, &oid)) {
 				struct commit *commit;
 				oidset_insert(common, &oid);
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index fcc5cc8ab0..98e1442cbf 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -404,6 +404,36 @@ test_expect_success 'in_vain not triggered before first ACK' '
 	test_i18ngrep "Total 3 " trace
 '
 
+test_expect_success 'in_vain resetted upon ACK' '
+	rm -rf myserver myclient trace &&
+	git init myserver &&
+
+	# Linked list of commits on master. The first is common; the rest are
+	# not.
+	test_commit -C myserver first_master_commit &&
+	git clone "file://$(pwd)/myserver" myclient &&
+	test_commit_bulk -C myclient 255 &&
+
+	# Another linked list of commits on anotherbranch with no connection to
+	# master. The first is common; the rest are not.
+	git -C myserver checkout --orphan anotherbranch &&
+	test_commit -C myserver first_anotherbranch_commit &&
+	git -C myclient fetch origin anotherbranch:refs/heads/anotherbranch &&
+	git -C myclient checkout anotherbranch &&
+	test_commit_bulk -C myclient 255 &&
+
+	# The new commit that the client wants to fetch.
+	git -C myserver checkout master &&
+	test_commit -C myserver to_fetch &&
+
+	# The client will send (as "have"s) all 256 commits in anotherbranch
+	# first. The 256th commit is common between the client and the server,
+	# and should reset in_vain. This allows negotiation to continue until
+	# the client reports that first_anotherbranch_commit is common.
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C myclient fetch --progress origin master &&
+	test_i18ngrep "Total 3 " trace
+'
+
 test_expect_success 'fetch in shallow repo unreachable shallow objects' '
 	(
 		git clone --bare --branch B --single-branch "file://$(pwd)/." no-reflog &&

-- 
2.26.2.303.gf8c07b1a785-goog