devonfw#1130: improve behaviour on ambigous XPath match

Author: leonrohne27

cli/src/main/java/com/devonfw/tools/ide/merge/FileMerger.java

@@ -49,8 +49,7 @@ public final int merge(Path setup, Path update, EnvironmentVariables variables,
     try {
       doMerge(setup, update, variables, workspace);
     } catch (Exception e) {
-      this.context.error(e, "Failed to merge workspace file {} with update template {} and setup file {}!", workspace, update, setup);
-      return 1;
+      this.context.warning("Failed to merge workspace file {} with update template {} and setup file {}!", workspace, update, setup);
     }
     return 0;
   }

cli/src/main/java/com/devonfw/tools/ide/merge/xmlmerger/XmlMerger.java

@@ -4,7 +4,8 @@
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import javax.xml.namespace.QName;
+import java.util.HashSet;
+import java.util.Set;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.transform.OutputKeys;
@@ -111,20 +112,34 @@ public Document merge(XmlMergeDocument templateDocument, XmlMergeDocument worksp
     Path template = workspaceDocument.getPath();
     this.context.debug("Merging {} into {} ...", template, source);
     Element templateRoot = templateDocument.getRoot();
-    QName templateQName = XmlMergeSupport.getQualifiedName(templateRoot);
     Element workspaceRoot = workspaceDocument.getRoot();
-    QName workspaceQName = XmlMergeSupport.getQualifiedName(workspaceRoot);
-    if (templateQName.equals(workspaceQName)) {
+
+    if (templateRoot.getNodeName().equals(workspaceRoot.getNodeName())) {
       XmlMergeStrategy strategy = XmlMergeSupport.getMergeStrategy(templateRoot);
       if (strategy == null) {
         strategy = XmlMergeStrategy.COMBINE; // default strategy used as fallback
       }
-      ElementMatcher elementMatcher = new ElementMatcher(this.context);
-      strategy.merge(templateRoot, workspaceRoot, elementMatcher);
+
+      Set<String> seenElements = new HashSet<>();
+
+      NodeList templateChildren = templateRoot.getChildNodes();
+      for (int i = 0; i < templateChildren.getLength(); i++) {
+        Node templateNode = templateChildren.item(i);
+        if (templateNode.getNodeType() == Node.ELEMENT_NODE) {
+          Element templateElement = (Element) templateNode;
+          String elementQName = templateElement.getNodeName();
+
+          if (!seenElements.contains(elementQName)) {
+            strategy.merge(templateElement, workspaceRoot, new ElementMatcher(this.context));
+            seenElements.add(elementQName);
+          }
+        }
+      }
+
       resultDocument = workspaceDocument.getDocument();
     } else {
-      this.context.error("Cannot merge XML template {} with root {} into XML file {} with root {} as roots do not match.", templateDocument.getPath(),
-          templateQName, workspaceDocument.getPath(), workspaceQName);
+      this.context.warning("Cannot merge XML template {} with root {} into XML file {} with root {} as roots do not match.",
+          templateDocument.getPath(), templateRoot.getNodeName(), workspaceDocument.getPath(), workspaceRoot.getNodeName());
       return null;
     }
     return resultDocument;