[PATCH v2 16/16] clone: use git protocol for cloning shallow repo locally

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

clone_local() does not handle $SRC/shallow. It could be made so, but
it's simpler to use fetch-pack/upload-pack instead.

This used by be caught by the check in upload-pack, which is triggered
by transport_get_remote_refs(), even in local clone case. The check is
now gone and check_everything_connected() should catch the result
incomplete repo. But check_everything_connected() will soon be skipped
in local clone case, opening a door to corrupt repo. This patch should
close that door.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/clone.c  | 14 ++++++++++++--
 t/t5601-clone.sh |  7 +++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/builtin/clone.c b/builtin/clone.c
index 17f57cd..09e383e 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -789,8 +789,18 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	else
 		repo = repo_name;
 	is_local = option_local != 0 && path && !is_bundle;
-	if (is_local && option_depth)
-		warning(_("--depth is ignored in local clones; use file:// instead."));
+	if (is_local) {
+		struct strbuf sb = STRBUF_INIT;
+		if (option_depth)
+			warning(_("--depth is ignored in local clones; use file:// instead."));
+		strbuf_addf(&sb, "%s/shallow", path);
+		if (!access(sb.buf, F_OK)) {
+			if (option_local > 0)
+				warning(_("source repository is shallow, ignoring --local"));
+			is_local = 0;
+		}
+		strbuf_release(&sb);
+	}
 	if (option_local > 0 && !is_local)
 		warning(_("--local is ignored"));
 
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 0629149..35a2a3d 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -285,4 +285,11 @@ test_expect_success NOT_MINGW,NOT_CYGWIN 'clone local path foo:bar' '
 	git clone "./foo:bar" foobar
 '
 
+test_expect_success 'shallow clone locally' '
+	git clone --depth=1 --no-local src ssrrcc &&
+	git clone ssrrcc ddsstt &&
+	test_cmp ssrrcc/.git/shallow ddsstt/.git/shallow &&
+	( cd ddsstt && git fsck )
+'
+
 test_done
-- 
1.8.2.83.gc99314b