Index: conf/include-interpol.properties
===================================================================
--- conf/include-interpol.properties	Thu Oct 09 16:52:34 EST 2008
+++ conf/include-interpol.properties	Thu Oct 09 16:52:34 EST 2008
@@ -0,0 +1,4 @@
+include.interpol.loaded = true
+
+
+
Index: src/test/org/apache/commons/configuration/TestPropertiesConfiguration.java
===================================================================
--- src/test/org/apache/commons/configuration/TestPropertiesConfiguration.java	(revision 702743)
+++ src/test/org/apache/commons/configuration/TestPropertiesConfiguration.java	Thu Oct 09 16:56:51 EST 2008
@@ -113,6 +113,16 @@
         assertEquals("true", loaded);
     }
 
+    /**
+     * test if includes properties from interpolated file
+     * name get loaded
+     */
+    public void testLoadIncludeInterpol() throws Exception
+    {
+        String loaded = conf.getString("include.interpol.loaded");
+        assertEquals("true", loaded);
+    }
+
     public void testSetInclude() throws Exception
     {
         // change the include key
Index: src/java/org/apache/commons/configuration/PropertiesConfiguration.java
===================================================================
--- src/java/org/apache/commons/configuration/PropertiesConfiguration.java	(revision 702743)
+++ src/java/org/apache/commons/configuration/PropertiesConfiguration.java	Thu Oct 09 16:58:18 EST 2008
@@ -504,7 +504,7 @@
                 }
                 for (int i = 0; i < files.length; i++)
                 {
-                    loadIncludeFile(files[i].trim());
+                    loadIncludeFile(interpolate(files[i].trim()));
                 }
             }
             result = false;
Index: conf/test.properties
===================================================================
--- conf/test.properties	(revision 702743)
+++ conf/test.properties	Thu Oct 09 17:13:40 EST 2008
@@ -5,6 +5,9 @@
 
 include = include.properties
 
+include.file = include-interpol.properties
+include = ${include.file}
+
 test.unescape = This \n string \t contains \" escaped \\ character\u0073
 test.unescape.list-separator = This string contains \, an escaped list separator