Add innocuous warning message to catch erroneous ref="${refid}" stuff.

Suggested by Tim Ellison.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@473415 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -16,6 +16,9 @@ Fixed bugs:
 Other changes:
 --------------
 
+* Warn user when a reference in the form "${refid}" cannot be resolved as this
+  is a sign they probably meant "refid" (misuse of property expansion syntax).
+
 Changes from Ant 1.7.0Beta3 to Ant 1.7.0RC1
 ===========================================
 

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

@@ -1911,7 +1911,18 @@ public class Project implements ResourceFactory {
             return ret;
         }
         // Check for old id behaviour
-        return resolveIdReference(key, this);
+        ret = resolveIdReference(key, this);
+        if (ret == null && !key.equals(MagicNames.REFID_PROPERTY_HELPER)) {
+            Vector p = new Vector();
+            PropertyHelper.getPropertyHelper(this).parsePropertyString(
+                key, new Vector(), p);
+            if (p.size() == 1) {
+                log("Unresolvable reference " + key
+                    + " might be a misuse of property expansion syntax.",
+                    MSG_WARN);
+            }
+        }
+        return ret;
     }
 
     /**

src/tests/antunit/core/ref-psyntax-hint.xml

@@ -0,0 +1,9 @@
+<project xmlns:au="antlib:org.apache.ant.antunit">
+  <target name="testIt">
+    <au:expectfailure>
+      <pathconvert refid="${foo}" />
+    </au:expectfailure>
+    <au:assertLogContains level="warning"
+      text="Unresolvable reference $${foo} might be a misuse of property expansion syntax." />
+  </target>
+</project>