Merge pull request src-d#640 from cesanta/fixdirsymlink

utils: merkletrie, filesystem fix symlinks to dir

Author: mcuadros

utils/merkletrie/filesystem/node.go

@@ -77,6 +77,10 @@ func (n *node) NumChildren() (int, error) {
 }
 
 func (n *node) calculateChildren() error {
+	if !n.IsDir() {
+		return nil
+	}
+
 	if len(n.children) != 0 {
 		return nil
 	}

utils/merkletrie/filesystem/node_test.go

@@ -82,6 +82,42 @@ func (s *NoderSuite) TestDiffChangeContent(c *C) {
 	c.Assert(ch, HasLen, 1)
 }
 
+func (s *NoderSuite) TestDiffSymlinkDirOnA(c *C) {
+	fsA := memfs.New()
+	WriteFile(fsA, "qux/qux", []byte("foo"), 0644)
+
+	fsB := memfs.New()
+	fsB.Symlink("qux", "foo")
+	WriteFile(fsB, "qux/qux", []byte("foo"), 0644)
+
+	ch, err := merkletrie.DiffTree(
+		NewRootNode(fsA, nil),
+		NewRootNode(fsB, nil),
+		IsEquals,
+	)
+
+	c.Assert(err, IsNil)
+	c.Assert(ch, HasLen, 1)
+}
+
+func (s *NoderSuite) TestDiffSymlinkDirOnB(c *C) {
+	fsA := memfs.New()
+	fsA.Symlink("qux", "foo")
+	WriteFile(fsA, "qux/qux", []byte("foo"), 0644)
+
+	fsB := memfs.New()
+	WriteFile(fsB, "qux/qux", []byte("foo"), 0644)
+
+	ch, err := merkletrie.DiffTree(
+		NewRootNode(fsA, nil),
+		NewRootNode(fsB, nil),
+		IsEquals,
+	)
+
+	c.Assert(err, IsNil)
+	c.Assert(ch, HasLen, 1)
+}
+
 func (s *NoderSuite) TestDiffChangeMissing(c *C) {
 	fsA := memfs.New()
 	WriteFile(fsA, "foo", []byte("foo"), 0644)