tweak

dom/node_element.go

@@ -47,11 +47,7 @@ func (n *Element) SetNamespace(uri, prefix string, activate ...bool) error {
 		return errors.New("missing uri for SetNamespace")
 	}
 
-	root, err := doc.DocumentElement()
-	if err != nil {
-		return err
-	}
-	if _, err := clib.XMLSearchNs(doc, root, prefix); err != nil {
+	if oldNs, _ := clib.XMLSearchNs(doc, n, prefix); oldNs == 0 {
 		// Namespace not found, create a new one
 		ns, err := clib.XMLNewNs(n, uri, prefix)
 		if err != nil {

dom/node_test.go

@@ -243,19 +243,37 @@ func TestCreateElementNS(t *testing.T) {
 }
 
 func TestGH102(t *testing.T) {
-	root := CreateDocument()
-	doc, _ := root.CreateElement("Document")
-	_ = doc.SetNamespace("https://example.com", "ex")
-	_ = root.SetDocumentElement(doc)
-	test, _ := root.CreateElement("Test")
-	_ = test.SetNamespace("https://example.com", "ex")
-	_ = doc.AddChild(test)
-	test.SetNodeValue("test")
+	t.Run("child ns after parent ns", func(t *testing.T) {
+		root := CreateDocument()
+		doc, _ := root.CreateElement("Document")
+		_ = doc.SetNamespace("https://example.com", "ex")
+		test, _ := root.CreateElement("Test")
+		_ = doc.AddChild(test)
+		_ = root.SetDocumentElement(doc)
+		_ = test.SetNamespace("https://example.com", "ex")
+		test.SetNodeValue("test")
 
-	// root.Dump(true) should only contain one namespace declaration
-	// for the 'ex' prefix
-	dump := root.Dump(true)
-	count := strings.Count(dump, `xmlns:ex="https://example.com"`)
-	t.Logf("%s", dump)
-	require.Equal(t, 1, count, "expected only one namespace declaration for 'ex' prefix")
+		// root.Dump(true) should only contain one namespace declaration
+		// for the 'ex' prefix
+		dump := root.Dump(true)
+		count := strings.Count(dump, `xmlns:ex="https://example.com"`)
+		t.Logf("%s", dump)
+		require.Equal(t, 1, count, "expected only one namespace declaration for 'ex' prefix")
+	})
+
+	t.Run("parent ns after child ns", func(t *testing.T) {
+		root := CreateDocument()
+		doc, _ := root.CreateElement("Document")
+		//_ = doc.SetNamespace("https://example.com", "ex") // delete
+		_ = root.SetDocumentElement(doc)
+		test, _ := root.CreateElement("Test")
+		_ = test.SetNamespace("https://example.com", "ex")
+		_ = doc.SetNamespace("https://example.com", "ex") // move to here
+		_ = doc.AddChild(test)
+		test.SetNodeValue("test")
+		dump := root.Dump(true)
+		count := strings.Count(dump, `xmlns:ex="https://example.com"`)
+		t.Logf("%s", dump)
+		require.Equal(t, 2, count, "expected two namespace declaration for 'ex' prefix")
+	})
 }