Fix for default namespace overwritten by empty namespace

.pre-commit-config.yaml

@@ -13,6 +13,6 @@ repos:
  - id: check-json
  - id: check-added-large-files
  - repo: https://github.com/ejba/pre-commit-maven
- rev: v0.3.3
+ rev: v0.3.4
  hooks:
  - id: maven-spotless-apply

xoai-common/src/main/java/io/gdcc/xoai/xml/EchoElement.java

@@ -104,8 +104,8 @@ private void write(final XmlWriter writer, final InputStream inStream)
  private void addNamespaceIfRequired(XmlWriter writer, QName name) throws XMLStreamException {
  // Search for namespace in scope, starting from the root.
  for (Set<String> ancestorNamespaces : declaredPrefixes) {
- if (ancestorNamespaces.contains(
- name.getPrefix() + name.getNamespaceURI())) { // Prefixes might be reused.
+ if (ancestorNamespaces.contains(name.getPrefix() + name.getNamespaceURI())
+ || name.getNamespaceURI().isBlank()) { // Prefixes might be reused.
  return;
  }
  }

xoai-common/src/test/java/io/gdcc/xoai/tests/util/EchoElementTest.java

@@ -5,7 +5,6 @@
 
 import io.gdcc.xoai.xml.EchoElement;
 import io.gdcc.xoai.xml.XmlWriter;
-import io.gdcc.xoai.xmlio.exceptions.XmlWriteException;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -21,8 +20,7 @@ public class EchoElementTest {
  * are likely to be used later.
  */
  @Test
- public void handleEarlyNamespaceDeclarations()
- throws XMLStreamException, XmlWriteException, IOException {
+ public void handleEarlyNamespaceDeclarations() throws XMLStreamException {
  String xml =
  "<?xml version='1.0' encoding='UTF-8'?><oai_dc:dc"
  + " xmlns:oai_dc=\"http://www.openarchives.org/OAI/2.0/oai_dc/\""
@@ -46,8 +44,7 @@ public void handleEarlyNamespaceDeclarations()
  * a namespace declaration.
  */
  @Test
- public void repeatingNamespaceDeclarations()
- throws XMLStreamException, XmlWriteException, IOException {
+ public void repeatingNamespaceDeclarations() throws XMLStreamException {
  String xml =
  "<?xml version='1.0' encoding='UTF-8'?><oai_dc:dc"
  + " xmlns:oai_dc=\"http://www.openarchives.org/OAI/2.0/oai_dc/\""
@@ -69,7 +66,7 @@ public void repeatingNamespaceDeclarations()
  }
 
  @Test
- public void copyFromInputStream() throws XMLStreamException, XmlWriteException, IOException {
+ public void copyFromInputStream() throws XMLStreamException, IOException {
  // given
  String xml =
  "<?xml version='1.0' encoding='UTF-8'?><oai_dc:dc"
@@ -102,7 +99,48 @@ public void copyFromInputStream() throws XMLStreamException, XmlWriteException,
  assertThat("EchoElement handles InputStream", result, equalTo(xml));
  }
 
- private static String echoXml(String xml) throws XmlWriteException, XMLStreamException {
+ @Test
+ public void defaultNamespaceDeclaration() throws XMLStreamException {
+ // given
+ String xml =
+ "<?xml version='1.0' encoding='UTF-8'?>"
+ + "<TEI xmlns=\"http://www.tei-c.org/ns/1.0\">\n"
+ + " <teiHeader xmlns:xml=\"http://www.w3.org/XML/1998/namespace\""
+ + " xml:lang=\"de\">\n"
+ + " <fileDesc>\n"
+ + " <titleStmt>\n"
+ + " <title>Titel\n"
+ + " </title>\n"
+ + " <respStmt>\n"
+ + " <resp>Published by</resp>\n"
+ + " <name type=\"org\">Organisation</name>\n"
+ + " </respStmt>\n"
+ + " </titleStmt>\n"
+ + " <publicationStmt>\n"
+ + " <publisher>\n"
+ + " <name type=\"org\">Organisation</name>\n"
+ + " <ptr target=\"http://www.organisation.org\"/>\n"
+ + " </publisher>\n"
+ + " <date when=\"2022-11-30\" type=\"issued\">2022-11-30</date>\n"
+ + " <distributor>Handschriftenportal</distributor>\n"
+ + " <availability status=\"free\">\n"
+ + " <licence"
+ + " target=\"https://creativecommons.org/publicdomain/zero/1.0/deed.de\">\n"
+ + " </licence>\n"
+ + " </availability>\n"
+ + " <pubPlace>\n"
+ + " </pubPlace>\n"
+ + " </publicationStmt>\n"
+ + " </fileDesc>\n"
+ + " </teiHeader>\n"
+ + "</TEI>";
+
+ String result = echoXml(xml);
+
+ assertThat("EchoElement does not add empty namespaces", result, equalTo(xml));
+ }
+
+ private static String echoXml(String xml) throws XMLStreamException {
 
  final ByteArrayOutputStream resultStream = new ByteArrayOutputStream();