sync: overlap check is now filter-sensitive

Previously, the overlap check was based on simple prefix checks of the source and destination paths. Now it actually checks whether the destination is excluded via any filter rule or a "--exclude-if-present"-file.

fs/operations/operations_test.go

@@ -1253,6 +1253,93 @@ func TestOverlapping(t *testing.T) {
 	}
 }
 
+// testFs is for unit testing fs.Fs
+type testFs struct {
+	testFsInfo
+}
+
+func (i *testFs) List(ctx context.Context, dir string) (entries fs.DirEntries, err error) {
+	return nil, nil
+}
+
+func (i *testFs) NewObject(ctx context.Context, remote string) (fs.Object, error) { return nil, nil }
+
+func (i *testFs) Put(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
+	return nil, nil
+}
+
+func (i *testFs) Mkdir(ctx context.Context, dir string) error { return nil }
+
+func (i *testFs) Rmdir(ctx context.Context, dir string) error { return nil }
+
+// copied from TestOverlapping because the behavior of OverlappingFilterCheck should be identical to Overlapping
+// when no filters are set
+func TestOverlappingFilterCheckWithoutFilter(t *testing.T) {
+	ctx := context.Background()
+	src := &testFs{testFsInfo{name: "name", root: "root"}}
+	slash := string(os.PathSeparator) // native path separator
+	for _, test := range []struct {
+		name     string
+		root     string
+		expected bool
+	}{
+		{"name", "root", true},
+		{"namey", "root", false},
+		{"name", "rooty", false},
+		{"namey", "rooty", false},
+		{"name", "roo", false},
+		{"name", "root/toot", true},
+		{"name", "root/toot/", true},
+		{"name", "root" + slash + "toot", true},
+		{"name", "root" + slash + "toot" + slash, true},
+		{"name", "", true},
+		{"name", "/", true},
+	} {
+		dst := &testFs{testFsInfo{name: test.name, root: test.root}}
+		what := fmt.Sprintf("(%q,%q) vs (%q,%q)", src.name, src.root, dst.name, dst.root)
+		actual := operations.OverlappingFilterCheck(ctx, src, dst)
+		assert.Equal(t, test.expected, actual, what)
+		actual = operations.OverlappingFilterCheck(ctx, dst, src)
+		assert.Equal(t, test.expected, actual, what)
+	}
+}
+
+func TestOverlappingFilterCheckWithFilter(t *testing.T) {
+	ctx := context.Background()
+	fi, err := filter.NewFilter(nil)
+	require.NoError(t, err)
+	require.NoError(t, fi.Add(false, "*/exclude/"))
+	fi.Opt.ExcludeFile = ".ignore"
+	ctx = filter.ReplaceConfig(ctx, fi)
+
+	src := &testFs{testFsInfo{name: "name", root: "root"}}
+	slash := string(os.PathSeparator) // native path separator
+	for _, test := range []struct {
+		name     string
+		root     string
+		expected bool
+	}{
+		{"name", "root", true},
+		{"name", "root/", true},
+		{"name", "root" + slash, true},
+		{"name", "root/exclude", false},
+		{"name", "root/exclude/", false},
+		{"name", "root" + slash + "exclude", false},
+		{"name", "root" + slash + "exclude" + slash, false},
+		{"name", "root/.ignore", false},
+		{"name", "root" + slash + ".ignore", false},
+		{"namey", "root/include", false},
+		{"namey", "root/include/", false},
+		{"namey", "root" + slash + "include", false},
+		{"namey", "root" + slash + "include" + slash, false},
+	} {
+		dst := &testFs{testFsInfo{name: test.name, root: test.root}}
+		what := fmt.Sprintf("(%q,%q) vs (%q,%q)", src.name, src.root, dst.name, dst.root)
+		actual := operations.OverlappingFilterCheck(ctx, dst, src)
+		assert.Equal(t, test.expected, actual, what)
+	}
+}
+
 func TestListFormat(t *testing.T) {
 	item0 := &operations.ListJSONItem{
 		Path:      "a",