make nested text in <property> less intrusive on existing build files

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@809623 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Property.java

@@ -90,6 +90,7 @@ public class Property extends Task {
     protected String prefix;
     private Project fallback;
     private Object untypedValue;
+    private boolean valueAttributeUsed = false;
 
     protected boolean userProperty; // set read-only properties
     // CheckStyle:VisibilityModifier ON
@@ -161,6 +162,11 @@ public class Property extends Task {
      * @param value the value to use.
      */
     public void setValue(Object value) {
+        valueAttributeUsed = true;
+        internalSetValue(value);
+    }
+
+    private void internalSetValue(Object value) {
         this.untypedValue = value;
         //preserve protected string value for subclasses :(
         this.value = value == null ? null : value.toString();
@@ -182,12 +188,17 @@ public class Property extends Task {
      * @since Ant 1.8.0
      */
     public void addText(String msg) {
+        if (!valueAttributeUsed) {
         msg = getProject().replaceProperties(msg);
         String currentValue = getValue();
         if (currentValue != null) {
             msg = currentValue + msg;
         }
-        setValue(msg);
+        internalSetValue(msg);
+        } else if (msg.trim().length() > 0) {
+            throw new BuildException("can't combine nested text with value"
+                                     + " attribute");
+        }
     }
 
     /**

src/tests/antunit/taskdefs/property-test.xml

@@ -23,4 +23,18 @@
     <property name="foo">bar</property>
     <au:assertPropertyEquals name="foo" value="bar"/>
   </target>
+
+  <target name="testNoNestedTextButValueAttribute">
+    <property name="foo" value="bar">
+    </property>
+    <au:assertPropertyEquals name="foo" value="bar"/>
+  </target>
+
+  <target name="testNestedTextAndValueAttribute">
+    <au:expectfailure>
+      <property name="foo" value="bar">
+        hello
+      </property>
+    </au:expectfailure>
+  </target>
 </project>