test-lib-functions: use test-tool for [de]packetize()

The shell+perl "[de]packetize()" helper functions were added in
4414a15002 (t/lib-git-daemon: add network-protocol helpers,
2018-01-24), and around the same time we added the "pkt-line" helper
in 74e7002961 (test-pkt-line: introduce a packet-line test helper,
2018-03-14).

For some reason it seems we've mostly used the shell+perl version
instead of the helper since then. There were discussions around
88124ab263 (test-lib-functions: make packetize() more efficient,
2020-03-27) and cacae4329f (test-lib-functions: simplify packetize()
stdin code, 2020-03-29) to improve them and make them more efficient.

There was one good reason to do so, we needed an equivalent of
"test-tool pkt-line pack", but that command wasn't capable of handling
input with "\n" (a feature) or "\0" (just because it happens to be
printf-based under the hood).

Let's add a "pkt-line-raw" helper for that, and expose is at a
packetize_raw() to go with the existing packetize() on the shell
level, this gives us the smallest amount of change to the tests
themselves.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/helper/test-pkt-line.c

@@ -26,6 +26,16 @@ static void pack(int argc, const char **argv)
 	}
 }
 
+static void pack_raw_stdin(void)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	if (strbuf_read(&sb, 0, 0) < 0)
+		die_errno("failed to read from stdin");
+	packet_write(1, sb.buf, sb.len);
+	strbuf_release(&sb);
+}
+
 static void unpack(void)
 {
 	struct packet_reader reader;
@@ -110,6 +120,8 @@ int cmd__pkt_line(int argc, const char **argv)
 
 	if (!strcmp(argv[1], "pack"))
 		pack(argc - 2, argv + 2);
+	else if (!strcmp(argv[1], "pack-raw-stdin"))
+		pack_raw_stdin();
 	else if (!strcmp(argv[1], "unpack"))
 		unpack();
 	else if (!strcmp(argv[1], "unpack-sideband"))

t/t5411/once-0010-report-status-v1.sh

@@ -28,10 +28,10 @@ test_expect_success "proc-receive: report status v1" '
 		if test -z "$GIT_DEFAULT_HASH" || test "$GIT_DEFAULT_HASH" = "sha1"
 		then
 			printf "%s %s refs/heads/main\0report-status\n" \
-				$A $B | packetize
+				$A $B | packetize_raw
 		else
 			printf "%s %s refs/heads/main\0report-status object-format=$GIT_DEFAULT_HASH\n" \
-				$A $B | packetize
+				$A $B | packetize_raw
 		fi &&
 		printf "%s %s refs/for/main/topic1\n" \
 			$ZERO_OID $A | packetize &&

t/t5562-http-backend-content-length.sh

@@ -63,7 +63,7 @@ test_expect_success 'setup' '
 	hash_next=$(git commit-tree -p HEAD -m next HEAD^{tree}) &&
 	{
 		printf "%s %s refs/heads/newbranch\\0report-status object-format=%s\\n" \
-			"$ZERO_OID" "$hash_next" "$(test_oid algo)" | packetize &&
+			"$ZERO_OID" "$hash_next" "$(test_oid algo)" | packetize_raw
 		printf 0000 &&
 		echo "$hash_next" | git pack-objects --stdout
 	} >push_body &&

t/t5570-git-daemon.sh

@@ -194,7 +194,7 @@ test_expect_success 'hostname cannot break out of directory' '
 
 test_expect_success FAKENC 'hostname interpolation works after LF-stripping' '
 	{
-		printf "git-upload-pack /interp.git\n\0host=localhost" | packetize
+		printf "git-upload-pack /interp.git\n\0host=localhost" | packetize_raw
 		printf "0000"
 	} >input &&
 	fake_nc "$GIT_DAEMON_HOST_PORT" <input >output &&

t/test-lib-functions.sh

@@ -1437,46 +1437,24 @@ nongit () {
 	)
 } 7>&2 2>&4
 
-# convert function arguments or stdin (if not arguments given) to pktline
-# representation. If multiple arguments are given, they are separated by
-# whitespace and put in a single packet. Note that data containing NULs must be
-# given on stdin, and that empty input becomes an empty packet, not a flush
-# packet (for that you can just print 0000 yourself).
+# These functions are historical wrappers around "test-tool pkt-line"
+# for older tests. Use "test-tool pkt-line" itself in new tests.
 packetize () {
 	if test $# -gt 0
 	then
 		packet="$*"
 		printf '%04x%s' "$((4 + ${#packet}))" "$packet"
 	else
-		perl -e '
-			my $packet = do { local $/; <STDIN> };
-			printf "%04x%s", 4 + length($packet), $packet;
-		'
+		test-tool pkt-line pack
 	fi
 }
 
-# Parse the input as a series of pktlines, writing the result to stdout.
-# Sideband markers are removed automatically, and the output is routed to
-# stderr if appropriate.
-#
-# NUL bytes are converted to "\\0" for ease of parsing with text tools.
+packetize_raw () {
+	test-tool pkt-line pack-raw-stdin
+}
+
 depacketize () {
-	perl -e '
-		while (read(STDIN, $len, 4) == 4) {
-			if ($len eq "0000") {
-				print "FLUSH\n";
-			} else {
-				read(STDIN, $buf, hex($len) - 4);
-				$buf =~ s/\0/\\0/g;
-				if ($buf =~ s/^[\x2\x3]//) {
-					print STDERR $buf;
-				} else {
-					$buf =~ s/^\x1//;
-					print $buf;
-				}
-			}
-		}
-	'
+	test-tool pkt-line unpack
 }
 
 # Converts base-16 data into base-8. The output is given as a sequence of