Xpp3Dom.removeChild(int): fix childMap corruption with duplicate names

src/main/java/org/apache/maven/shared/utils/xml/Xpp3Dom.java

@@ -261,8 +261,22 @@ public int getChildCount() {
      */
     public void removeChild(int i) {
         Xpp3Dom child = childList.remove(i);
-        childMap.values().remove(child);
         child.setParent(null);
+
+        String name = child.getName();
+        if (childMap.get(name) == child) {
+            Xpp3Dom lastWithName = null;
+            for (Xpp3Dom c : childList) {
+                if (name.equals(c.getName())) {
+                    lastWithName = c;
+                }
+            }
+            if (lastWithName != null) {
+                childMap.put(name, lastWithName);
+            } else {
+                childMap.remove(name);
+            }
+        }
     }
 
     /**

src/test/java/org/apache/maven/shared/utils/xml/pull/Xpp3DomTest.java

@@ -42,6 +42,22 @@ private Xpp3Dom createElement(String element, String value) {
         return t1s1;
     }
 
+    @Test
+    public void removeChildByIndexUpdatesChildMap() {
+        Xpp3Dom parent = new Xpp3Dom("parent");
+        Xpp3Dom first = new Xpp3Dom("child");
+        first.setValue("first");
+        Xpp3Dom second = new Xpp3Dom("child");
+        second.setValue("second");
+        parent.addChild(first);
+        parent.addChild(second);
+
+        parent.removeChild(1);
+
+        assertEquals(1, parent.getChildCount());
+        assertEquals("first", parent.getChild("child").getValue());
+    }
+
     @Test
     public void mergePrecedenceSelfClosed() throws XmlPullParserException {
         Xpp3Dom parentConfig = build("<configuration><items><item/></items></configuration>");