Throw a BuildException when an attempt is made to use a property which has

not been set. Any build files which rely on non-set properties being passed
through untranslated will now break.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@268322 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -9,6 +9,10 @@ Changes that could break older environments:
 
 * <perforce> has been replaced by a number of new tasks.
 
+* Ant now throws a BuildException when an attempt is made to use a property which has
+  not been set. Any build files which rely on non-set properties being passed
+  through untranslated will now break.
+
 Other changes:
 --------------
 

src/main/org/apache/tools/ant/ProjectHelper.java

@@ -634,8 +634,12 @@ public class ProjectHelper {
                                              value );
                 }
                 String n=value.substring( pos+2, endName );
-                String v= (keys.containsKey(n)) ? (String) keys.get( n ) 
-                    : "${"+n+"}";
+                if (!keys.containsKey(n)) {
+                    throw new BuildException("Property ${" + n + "} has not been set");
+                }
+                
+                String v = (String) keys.get(n);
+                
                 //System.out.println("N: " + n + " " + " V:" + v);
                 sb.append( v );
                 prev=endName+1;