Fixed MultiDelimiterStringSearchInterpolator escape String code

Author: belingueres

src/main/java/org/codehaus/plexus/interpolation/multi/MultiDelimiterStringSearchInterpolator.java

@@ -201,13 +201,16 @@ private String interpolate( String input, RecursionInterceptor recursionIntercep
 
                 if ( startIdx >= 0 && escapeString != null && escapeString.length() > 0 )
                 {
-                    int startEscapeIdx = startIdx == 0 ? 0 : startIdx - escapeString.length();
+                    int startEscapeIdx = (startIdx == 0) ? 0 : startIdx - escapeString.length();
                     if ( startEscapeIdx >= 0 )
                     {
                         String escape = input.substring( startEscapeIdx, startIdx );
                         if ( escape != null && escapeString.equals( escape ) )
                         {
                             result.append( wholeExpr );
+                            if (startEscapeIdx > 0) {
+                            	--startEscapeIdx;
+                            }
                             result.replace( startEscapeIdx, startEscapeIdx + escapeString.length(), "" );
                             continue;
                         }

src/test/java/org/codehaus/plexus/interpolation/multi/MultiDelimiterStringSearchInterpolatorTest.java

@@ -85,4 +85,22 @@ public void testInterpolationWithMultipleEscapes()
             assertEquals( "#${first} and ${last}", result );
         }
 
+    public void testInterpolationWithMultipleEscapes2()
+            throws InterpolationException
+        {
+            Map ctx = new HashMap();
+            ctx.put( "name", "User" );
+            ctx.put( "otherName", "#${first} and ##${last}" );
+
+            String input = "${otherName}";
+
+            ValueSource vs = new MapBasedValueSource( ctx );
+            MultiDelimiterStringSearchInterpolator interpolator = new MultiDelimiterStringSearchInterpolator()
+                                                                          .withValueSource( vs );
+            interpolator.setEscapeString("#");
+
+            String result = interpolator.interpolate( input );
+
+            assertEquals( "${first} and #${last}", result );
+        }
 }