builtin/clone.c: add --reject-shallow option

In some scenarios, users may want more history than the repository
offered for cloning, which happens to be a shallow repository, can
give them. But because users don't know it is a shallow repository
until they download it to local, we may want to refuse to clone
this kind of repository, without creating any unnecessary files.

The '--depth=x' option cannot be used as a solution; the source may
be deep enough to give us 'x' commits when cloned, but the user may
later need to deepen the history to arbitrary depth.

Teach '--reject-shallow' option to "git clone" to abort as soon as
we find out that we are cloning from a shallow repository.

Signed-off-by: Li Linchao <lilinchao@oschina.cn>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 60 insertions, 1 deletions

diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index e7e6c08..329ae59 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -759,6 +759,15 @@ test_expect_success 'partial clone using HTTP' '
 	partial_clone "$HTTPD_DOCUMENT_ROOT_PATH/server" "$HTTPD_URL/smart/server"
 '
 
+test_expect_success 'reject cloning shallow repository using HTTP' '
+	test_when_finished "rm -rf repo" &&
+	git clone --bare --no-local --depth=1 src "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+	test_must_fail git clone --reject-shallow $HTTPD_URL/smart/repo.git repo 2>err &&
+	test_i18ngrep -e "source repository is shallow, reject to clone." err &&
+
+	git clone --no-reject-shallow $HTTPD_URL/smart/repo.git repo
+'
+
 # DO NOT add non-httpd-specific tests here, because the last part of this
 # test script is only executed when httpd is available and enabled.
 
diff --git a/t/t5606-clone-options.sh b/t/t5606-clone-options.sh
index 428b0aa..3a595c0 100755
--- a/t/t5606-clone-options.sh
+++ b/t/t5606-clone-options.sh
@@ -11,7 +11,8 @@ test_expect_success 'setup' '
 	mkdir parent &&
 	(cd parent && git init &&
 	 echo one >file && git add file &&
-	 git commit -m one)
+	 git commit -m one) &&
+	git clone --depth=1 --no-local parent shallow-repo
 
 '
 
@@ -45,6 +46,30 @@ test_expect_success 'disallows --bare with --separate-git-dir' '
 
 '
 
+test_expect_success 'reject cloning shallow repository' '
+	test_when_finished "rm -rf repo" &&
+	test_must_fail git clone --reject-shallow shallow-repo out 2>err &&
+	test_i18ngrep -e "source repository is shallow, reject to clone." err &&
+
+	git clone --no-reject-shallow shallow-repo repo
+'
+
+test_expect_success 'reject cloning non-local shallow repository' '
+	test_when_finished "rm -rf repo" &&
+	test_must_fail git clone --reject-shallow --no-local shallow-repo out 2>err &&
+	test_i18ngrep -e "source repository is shallow, reject to clone." err &&
+
+	git clone --no-reject-shallow --no-local shallow-repo repo
+'
+
+test_expect_success 'succeed cloning normal repository' '
+	test_when_finished "rm -rf chilad1 child2 child3 child4 " &&
+	git clone --reject-shallow parent child1 &&
+	git clone --reject-shallow --no-local parent child2 &&
+	git clone --no-reject-shallow parent child3 &&
+	git clone --no-reject-shallow --no-local parent child4
+'
+
 test_expect_success 'uses "origin" for default remote name' '
 
 	git clone parent clone-default-origin &&
diff --git a/t/t5611-clone-config.sh b/t/t5611-clone-config.sh
index 9f555b8..f8625f9 100755
--- a/t/t5611-clone-config.sh
+++ b/t/t5611-clone-config.sh
@@ -95,6 +95,31 @@ test_expect_success 'clone -c remote.<remote>.fetch=<refspec> --origin=<name>' '
 	test_cmp expect actual
 '
 
+test_expect_success 'set up shallow repository' '
+	git clone --depth=1 --no-local . shallow-repo
+'
+
+test_expect_success 'clone.rejectshallow=true should reject cloning shallow repo' '
+	test_when_finished "rm -rf out" &&
+	test_must_fail git -c clone.rejectshallow=true clone --no-local shallow-repo out 2>err &&
+	test_i18ngrep -e "source repository is shallow, reject to clone." err &&
+
+	git -c clone.rejectshallow=false clone --no-local shallow-repo out
+'
+
+test_expect_success 'option --[no-]reject-shallow override clone.rejectshallow config' '
+	test_when_finished "rm -rf out" &&
+	test_must_fail git -c clone.rejectshallow=false clone --reject-shallow --no-local shallow-repo out 2>err &&
+	test_i18ngrep -e "source repository is shallow, reject to clone." err &&
+
+	git -c clone.rejectshallow=true clone --no-reject-shallow --no-local shallow-repo out
+'
+
+test_expect_success 'clone.rejectshallow=true should succeed cloning normal repo' '
+	test_when_finished "rm -rf out" &&
+	git -c clone.rejectshallow=true clone --no-local . out
+'
+
 test_expect_success MINGW 'clone -c core.hideDotFiles' '
 	test_commit attributes .gitattributes "" &&
 	rm -rf child &&