[MNG-4421] Warn regarding old-style references when used in a project build

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-3/trunk@831579 13f79535-47bb-0310-9956-ffa450edef68

maven-model-builder/src/main/java/org/apache/maven/model/interpolation/AbstractStringBasedModelInterpolator.java

@@ -104,12 +104,23 @@ public abstract class AbstractStringBasedModelInterpolator
         recursionInterceptor = new PrefixAwareRecursionInterceptor( PROJECT_PREFIXES );
     }
 
-    protected List<ValueSource> createValueSources( final Model model, final File projectDir, final ModelBuildingRequest config )
+    protected List<ValueSource> createValueSources( final Model model, final File projectDir,
+                                                    final ModelBuildingRequest config,
+                                                    final ModelProblemCollector problems )
     {
         Properties modelProperties = model.getProperties();
 
         ValueSource modelValueSource1 = new PrefixedObjectValueSource( PROJECT_PREFIXES, model, false );
+        if ( config.getValidationLevel() >= ModelBuildingRequest.VALIDATION_LEVEL_MAVEN_2_0 )
+        {
+            modelValueSource1 = new ProblemDetectingValueSource( modelValueSource1, "pom.", "project.", problems );
+        }
+
         ValueSource modelValueSource2 = new ObjectBasedValueSource( model );
+        if ( config.getValidationLevel() >= ModelBuildingRequest.VALIDATION_LEVEL_MAVEN_2_0 )
+        {
+            modelValueSource2 = new ProblemDetectingValueSource( modelValueSource2, "", "project.", problems );
+        }
 
         // NOTE: Order counts here!
         List<ValueSource> valueSources = new ArrayList<ValueSource>( 9 );

maven-model-builder/src/main/java/org/apache/maven/model/interpolation/ProblemDetectingValueSource.java

@@ -0,0 +1,80 @@
+package org.apache.maven.model.interpolation;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.List;
+
+import org.apache.maven.model.building.ModelProblemCollector;
+import org.codehaus.plexus.interpolation.ValueSource;
+
+/**
+ * Wraps another value source and intercepts interpolated expressions, checking for problems.
+ * 
+ * @author Benjamin Bentmann
+ */
+class ProblemDetectingValueSource
+    implements ValueSource
+{
+
+    private final ValueSource valueSource;
+
+    private final String bannedPrefix;
+
+    private final String newPrefix;
+
+    private final ModelProblemCollector problems;
+
+    public ProblemDetectingValueSource( ValueSource valueSource, String bannedPrefix, String newPrefix,
+                                        ModelProblemCollector problems )
+    {
+        this.valueSource = valueSource;
+        this.bannedPrefix = bannedPrefix;
+        this.newPrefix = newPrefix;
+        this.problems = problems;
+    }
+
+    public Object getValue( String expression )
+    {
+        Object value = valueSource.getValue( expression );
+
+        if ( value != null && expression.startsWith( bannedPrefix ) )
+        {
+            String msg = "The expression ${" + expression + "} is deprecated.";
+            if ( newPrefix != null && newPrefix.length() > 0 )
+            {
+                msg += " Please use ${" + newPrefix + expression.substring( bannedPrefix.length() ) + "} instead.";
+            }
+            problems.addWarning( msg );
+        }
+
+        return value;
+    }
+
+    public List getFeedback()
+    {
+        return valueSource.getFeedback();
+    }
+
+    public void clearFeedback()
+    {
+        valueSource.clearFeedback();
+    }
+
+}

maven-model-builder/src/main/java/org/apache/maven/model/interpolation/StringSearchModelInterpolator.java

@@ -60,7 +60,7 @@ public class StringSearchModelInterpolator
     {
         try
         {
-            List<? extends ValueSource> valueSources = createValueSources( model, projectDir, config );
+            List<? extends ValueSource> valueSources = createValueSources( model, projectDir, config, problems );
             List<? extends InterpolationPostProcessor> postProcessors = createPostProcessors( model, projectDir, config );
 
             InterpolateObjectAction action =