transfer.unpackLimit: fetch/receive.unpackLimit takes precedence

The transfer.unpackLimit configuration variable is documented to be
used only as a fallback value when the more operation-specific
fetch.unpackLimit and receive.unpackLimit variables are not set, but
the implementation had the precedence reversed.  Apparently this was
broken since the transfer.unpackLimit was introduced in e28714c5
(Consolidate {receive,fetch}.unpackLimit, 2007-01-24).

Often when documentation and code have diverged for so long, we
prefer to change the documentation instead, to avoid disrupting
users.  But doing so would make these weirdly unlike most other
"specific overrides general" config options. And the fact that the
bug has existed for so long without anyone noticing implies to me
that nobody really tries to mix and match them much.

Signed-off-by: Taylor Santiago <taylorsantiago@google.com>
[jc: rewrote the log message, added tests, covered receive-pack as well]
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/receive-pack.c

@@ -2524,10 +2524,10 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	if (cert_nonce_seed)
 		push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));
 
-	if (0 <= transfer_unpack_limit)
-		unpack_limit = transfer_unpack_limit;
-	else if (0 <= receive_unpack_limit)
+	if (0 <= receive_unpack_limit)
 		unpack_limit = receive_unpack_limit;
+	else if (0 <= transfer_unpack_limit)
+		unpack_limit = transfer_unpack_limit;
 
 	switch (determine_protocol_version_server()) {
 	case protocol_v2:

fetch-pack.c

@@ -1911,10 +1911,10 @@ static void fetch_pack_setup(void)
 	if (did_setup)
 		return;
 	fetch_pack_config();
-	if (0 <= transfer_unpack_limit)
-		unpack_limit = transfer_unpack_limit;
-	else if (0 <= fetch_unpack_limit)
+	if (0 <= fetch_unpack_limit)
 		unpack_limit = fetch_unpack_limit;
+	else if (0 <= transfer_unpack_limit)
+		unpack_limit = transfer_unpack_limit;
 	did_setup = 1;
 }
 

t/t5510-fetch.sh

@@ -1127,6 +1127,52 @@ do
 	'
 done
 
+test_expect_success 'prepare source branch' '
+	echo one >onebranch &&
+	git checkout --orphan onebranch &&
+	git rm --cached -r . &&
+	git add onebranch &&
+	git commit -m onebranch &&
+	git rev-list --objects onebranch -- >actual &&
+	# 3 objects should be created, at least ...
+	test 3 -le $(wc -l <actual)
+'
+
+validate_store_type () {
+	git -C dest count-objects -v >actual &&
+	case "$store_type" in
+	packed)
+		grep "^count: 0$" actual ;;
+	loose)
+		grep "^packs: 0$" actual ;;
+	esac || {
+		echo "store_type is $store_type"
+		cat actual
+		false
+	}
+}
+
+test_unpack_limit () {
+	store_type=$1
+
+	case "$store_type" in
+	packed) fetch_limit=1 transfer_limit=10000 ;;
+	loose) fetch_limit=10000 transfer_limit=1 ;;
+	esac
+
+	test_expect_success "fetch trumps transfer limit" '
+		rm -fr dest &&
+		git --bare init dest &&
+		git -C dest config fetch.unpacklimit $fetch_limit &&
+		git -C dest config transfer.unpacklimit $transfer_limit &&
+		git -C dest fetch .. onebranch &&
+		validate_store_type
+	'
+}
+
+test_unpack_limit packed
+test_unpack_limit loose
+
 setup_negotiation_tip () {
 	SERVER="$1"
 	URL="$2"

t/t5546-receive-limits.sh

@@ -9,10 +9,26 @@ TEST_PASSES_SANITIZE_LEAK=true
 # When the limit is 1, `git receive-pack` will call `git index-pack`.
 # When the limit is 10000, `git receive-pack` will call `git unpack-objects`.
 
+validate_store_type () {
+	git -C dest count-objects -v >actual &&
+	case "$store_type" in
+	index)
+		grep "^count: 0$" actual ;;
+	unpack)
+		grep "^packs: 0$" actual ;;
+	esac || {
+		echo "store_type is $store_type"
+		cat actual
+		false;
+	}
+}
+
 test_pack_input_limit () {
-	case "$1" in
-	index) unpack_limit=1 ;;
-	unpack) unpack_limit=10000 ;;
+	store_type=$1
+
+	case "$store_type" in
+	index) unpack_limit=1 other_limit=10000 ;;
+	unpack) unpack_limit=10000 other_limit=1 ;;
 	esac
 
 	test_expect_success 'prepare destination repository' '
@@ -43,6 +59,19 @@ test_pack_input_limit () {
 		git --git-dir=dest config receive.maxInputSize 0 &&
 		git push dest HEAD
 	'
+
+	test_expect_success 'prepare destination repository (once more)' '
+		rm -fr dest &&
+		git --bare init dest
+	'
+
+	test_expect_success 'receive trumps transfer' '
+		git --git-dir=dest config receive.unpacklimit "$unpack_limit" &&
+		git --git-dir=dest config transfer.unpacklimit "$other_limit" &&
+		git push dest HEAD &&
+		validate_store_type
+	'
+
 }
 
 test_expect_success "create known-size (1024 bytes) commit" '