lib/config, lib/ignore: Write Windows line endings (fixes #7115) (#8052)

lib/config/config_test.go

@@ -594,6 +594,41 @@ func TestNewSaveLoad(t *testing.T) {
 	}
 }
 
+func TestWindowsLineEndings(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skip("Windows specific")
+	}
+
+	dir, err := os.MkdirTemp("", "syncthing-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	path := filepath.Join(dir, "config.xml")
+	os.Remove(path)
+	defer os.Remove(path)
+
+	intCfg := New(device1)
+	cfg := wrap(path, intCfg, device1)
+	defer cfg.stop()
+
+	if err := cfg.Save(); err != nil {
+		t.Error(err)
+	}
+
+	bs, err := os.ReadFile(path)
+	if err != nil {
+		t.Error(err)
+	}
+
+	unixLineEndings := bytes.Count(bs, []byte("\n"))
+	windowsLineEndings := bytes.Count(bs, []byte("\r\n"))
+	if unixLineEndings == 0 || windowsLineEndings != unixLineEndings {
+		t.Error("expected there to be a non-zero number of Windows line endings")
+	}
+}
+
 func TestPrepare(t *testing.T) {
 	var cfg Configuration
 

lib/config/wrapper.go

@@ -502,7 +502,7 @@ func (w *wrapper) Save() error {
 		return err
 	}
 
-	if err := w.cfg.WriteXML(fd); err != nil {
+	if err := w.cfg.WriteXML(osutil.LineEndingsWriter(fd)); err != nil {
 		l.Debugln("WriteXML:", err)
 		fd.Close()
 		return err