Merge branch 'nd/http-fetch-shallow-fix'

Attempting to deepen a shallow repository by fetching over smart
HTTP transport failed in the protocol exchange, when no-done
extension was used.  The fetching side waited for the list of
shallow boundary commits after the sending end stopped talking to
it.

* nd/http-fetch-shallow-fix:
  t5537: move http tests out to t5539
  fetch-pack: fix deepen shallow over smart http with no-done cap
  protocol-capabilities.txt: document no-done
  protocol-capabilities.txt: refer multi_ack_detailed back to pack-protocol.txt
  pack-protocol.txt: clarify 'obj-id' in the last ACK after 'done'
  test: rename http fetch and push test files

Documentation/technical/pack-protocol.txt

@@ -338,7 +338,8 @@ during a prior round.  This helps to ensure that at least one common
 ancestor is found before we give up entirely.
 
 Once the 'done' line is read from the client, the server will either
-send a final 'ACK obj-id' or it will send a 'NAK'. The server only sends
+send a final 'ACK obj-id' or it will send a 'NAK'. 'obj-id' is the object
+name of the last commit determined to be common. The server only sends
 ACK after 'done' if there is at least one common base and multi_ack or
 multi_ack_detailed is enabled. The server always sends NAK after 'done'
 if there is no common base found.

Documentation/technical/protocol-capabilities.txt

@@ -69,6 +69,24 @@ ends.
 Without multi_ack the client would have sent that c-b-a chain anyway,
 interleaved with S-R-Q.
 
+multi_ack_detailed
+------------------
+This is an extension of multi_ack that permits client to better
+understand the server's in-memory state. See pack-protocol.txt,
+section "Packfile Negotiation" for more information.
+
+no-done
+-------
+This capability should only be used with the smart HTTP protocol. If
+multi_ack_detailed and no-done are both present, then the sender is
+free to immediately send a pack following its first "ACK obj-id ready"
+message.
+
+Without no-done in the smart HTTP protocol, the server session would
+end and the client has to make another trip to send "done" before
+the server can send the pack. no-done removes the last round and
+thus slightly reduces latency.
+
 thin-pack
 ---------
 

fetch-pack.c

@@ -439,7 +439,8 @@ static int find_common(struct fetch_pack_args *args,
 	}
 	strbuf_release(&req_buf);
 
-	consume_shallow_list(args, fd[0]);
+	if (!got_ready || !no_done)
+		consume_shallow_list(args, fd[0]);
 	while (flushes || multi_ack) {
 		int ack = get_ack(fd[0], result_sha1);
 		if (ack) {

t/t5537-fetch-shallow.sh

@@ -173,31 +173,4 @@ EOF
 	)
 '
 
-if test -n "$NO_CURL" -o -z "$GIT_TEST_HTTPD"; then
-	say 'skipping remaining tests, git built without http support'
-	test_done
-fi
-
-. "$TEST_DIRECTORY"/lib-httpd.sh
-start_httpd
-
-test_expect_success 'clone http repository' '
-	git clone --bare --no-local shallow "$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 &&
-7
-6
-5
-4
-3
-EOF
-	test_cmp expect actual
-	)
-'
-
-stop_httpd
 test_done

t/t5539-fetch-http-shallow.sh

@@ -0,0 +1,82 @@
+#!/bin/sh
+
+test_description='fetch/clone from a shallow clone over http'
+
+. ./test-lib.sh
+
+if test -n "$NO_CURL"; then
+	skip_all='skipping test, git built without http support'
+	test_done
+fi
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+commit() {
+	echo "$1" >tracked &&
+	git add tracked &&
+	git commit -m "$1"
+}
+
+test_expect_success 'setup shallow clone' '
+	commit 1 &&
+	commit 2 &&
+	commit 3 &&
+	commit 4 &&
+	commit 5 &&
+	commit 6 &&
+	commit 7 &&
+	git clone --no-local --depth=5 .git shallow &&
+	git config --global transfer.fsckObjects true
+'
+
+test_expect_success 'clone http repository' '
+	git clone --bare --no-local shallow "$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 &&
+7
+6
+5
+4
+3
+EOF
+	test_cmp expect actual
+	)
+'
+
+# This test is tricky. We need large enough "have"s that fetch-pack
+# will put pkt-flush in between. Then we need a "have" the server
+# does not have, it'll send "ACK %s ready"
+test_expect_success 'no shallow lines after receiving ACK ready' '
+	(
+		cd shallow &&
+		for i in $(test_seq 15)
+		do
+			git checkout --orphan unrelated$i &&
+			test_commit unrelated$i &&
+			git push -q "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
+				refs/heads/unrelated$i:refs/heads/unrelated$i &&
+			git push -q ../clone/.git \
+				refs/heads/unrelated$i:refs/heads/unrelated$i ||
+			exit 1
+		done &&
+		git checkout master &&
+		test_commit new &&
+		git push  "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" master
+	) &&
+	(
+		cd clone &&
+		git checkout --orphan newnew &&
+		test_commit new-too &&
+		GIT_TRACE_PACKET="$TRASH_DIRECTORY/trace" git fetch --depth=2 &&
+		grep "fetch-pack< ACK .* ready" ../trace &&
+		! grep "fetch-pack> done" ../trace
+	)
+'
+
+stop_httpd
+test_done