clone: add --single-branch to fetch only one branch

When --single-branch is given, only one branch, either HEAD or one
specified by --branch, will be fetched. Also only tags that point to
the downloaded history are fetched.

This helps most in shallow clones, where it can reduce the download to
minimum and that is why it is enabled by default when --depth is given.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 71 insertions, 1 deletions

diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 9bf69e9..7e85c71 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -114,8 +114,19 @@ pull_to_client 2nd "refs/heads/B" $((64*3))
 
 pull_to_client 3rd "refs/heads/A" $((1*3))
 
+test_expect_success 'single branch clone' '
+	git clone --single-branch "file://$(pwd)/." singlebranch
+'
+
+test_expect_success 'single branch object count' '
+	GIT_DIR=singlebranch/.git git count-objects -v |
+		grep "^in-pack:" > count.singlebranch &&
+	echo "in-pack: 198" >expected &&
+	test_cmp expected count.singlebranch
+'
+
 test_expect_success 'clone shallow' '
-	git clone --depth 2 "file://$(pwd)/." shallow
+	git clone --no-single-branch --depth 2 "file://$(pwd)/." shallow
 '
 
 test_expect_success 'clone shallow object count' '
@@ -248,4 +259,63 @@ test_expect_success 'clone shallow object count' '
 	grep "^count: 52" count.shallow
 '
 
+test_expect_success 'clone shallow without --no-single-branch' '
+	git clone --depth 1 "file://$(pwd)/." shallow2
+'
+
+test_expect_success 'clone shallow object count' '
+	(
+		cd shallow2 &&
+		git count-objects -v
+	) > count.shallow2 &&
+	grep "^in-pack: 6" count.shallow2
+'
+
+test_expect_success 'clone shallow with --branch' '
+	git clone --depth 1 --branch A "file://$(pwd)/." shallow3
+'
+
+test_expect_success 'clone shallow object count' '
+	echo "in-pack: 12" > count3.expected &&
+	GIT_DIR=shallow3/.git git count-objects -v |
+		grep "^in-pack" > count3.actual &&
+	test_cmp count3.expected count3.actual
+'
+
+test_expect_success 'clone shallow with nonexistent --branch' '
+	git clone --depth 1 --branch Z "file://$(pwd)/." shallow4 &&
+	GIT_DIR=shallow4/.git git rev-parse HEAD >actual &&
+	git rev-parse HEAD >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'clone shallow with detached HEAD' '
+	git checkout HEAD^ &&
+	git clone --depth 1 "file://$(pwd)/." shallow5 &&
+	git checkout - &&
+	GIT_DIR=shallow5/.git git rev-parse HEAD >actual &&
+	git rev-parse HEAD^ >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'shallow clone pulling tags' '
+	git tag -a -m A TAGA1 A &&
+	git tag -a -m B TAGB1 B &&
+	git tag TAGA2 A &&
+	git tag TAGB2 B &&
+	git clone --depth 1 "file://$(pwd)/." shallow6 &&
+
+	cat >taglist.expected <<\EOF &&
+TAGB1
+TAGB2
+EOF
+	GIT_DIR=shallow6/.git git tag -l >taglist.actual &&
+	test_cmp taglist.expected taglist.actual &&
+
+	echo "in-pack: 7" > count6.expected &&
+	GIT_DIR=shallow6/.git git count-objects -v |
+		grep "^in-pack" > count6.actual &&
+	test_cmp count6.expected count6.actual
+'
+
 test_done