Make <available> less noisy.

Merged from the 1.5 branch.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273204 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -44,6 +44,9 @@ Other changes:
 * Appendix E of Java Development with Ant (Loughran/Hatcher)
   contributed to the docs
 
+* <available> will only print deprecration warnings if it is actually
+  used to change the value of a property.
+
 Changes from Ant 1.5beta3 to Ant 1.5
 ====================================
 

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

@@ -245,7 +245,8 @@ public class Available extends Task implements Condition {
         isTask = true;
         try {
             if (eval()) {
-                if (null != getProject().getProperty(property)) {
+                String oldvalue = getProject().getProperty(property);
+                if (null != oldvalue && !oldvalue.equals(value)) {
                     log("DEPRECATED - <available> used to override an existing"
                         + " property."
                         + StringUtils.LINE_SEP

src/script/antRun

@@ -1,6 +1,6 @@
 #! /bin/sh
 
-#   Copyright (c) 2001 The Apache Software Foundation.  All rights
+#   Copyright (c) 2001-2002 The Apache Software Foundation.  All rights
 #   reserved.
 
 # Args: DIR command