[MNG-7407] Introduce a ModelVersionProcessor component to make CI Friendly Versions pluggable

This closes #675

maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuilderFactory.java

@@ -26,7 +26,9 @@ import org.apache.maven.model.composition.DefaultDependencyManagementImporter;
 import org.apache.maven.model.composition.DependencyManagementImporter;
 import org.apache.maven.model.inheritance.DefaultInheritanceAssembler;
 import org.apache.maven.model.inheritance.InheritanceAssembler;
+import org.apache.maven.model.interpolation.DefaultModelVersionProcessor;
 import org.apache.maven.model.interpolation.ModelInterpolator;
+import org.apache.maven.model.interpolation.ModelVersionProcessor;
 import org.apache.maven.model.interpolation.StringVisitorModelInterpolator;
 import org.apache.maven.model.io.DefaultModelReader;
 import org.apache.maven.model.io.ModelReader;
@@ -259,12 +261,19 @@ public class DefaultModelBuilderFactory
     {
         UrlNormalizer normalizer = newUrlNormalizer();
         PathTranslator pathTranslator = newPathTranslator();
-        return new StringVisitorModelInterpolator( pathTranslator, normalizer );
+        ModelVersionProcessor versionProcessor = newModelVersionPropertiesProcessor();
+        return new StringVisitorModelInterpolator( pathTranslator, normalizer, versionProcessor );
+    }
+
+    protected ModelVersionProcessor newModelVersionPropertiesProcessor()
+    {
+        return new DefaultModelVersionProcessor();
     }
 
     protected ModelValidator newModelValidator()
     {
-        return new DefaultModelValidator();
+        ModelVersionProcessor processor = newModelVersionPropertiesProcessor();
+        return new DefaultModelValidator( processor );
     }
 
     protected ModelNormalizer newModelNormalizer()

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

@@ -52,12 +52,6 @@ import org.codehaus.plexus.interpolation.ValueSource;
 public abstract class AbstractStringBasedModelInterpolator
     implements ModelInterpolator
 {
-    public static final String SHA1_PROPERTY = "sha1";
-
-    public static final String CHANGELIST_PROPERTY = "changelist";
-
-    public static final String REVISION_PROPERTY = "revision";
-
     private static final List<String> PROJECT_PREFIXES = Arrays.asList( "pom.", "project." );
 
     private static final Collection<String> TRANSLATED_PATH_EXPRESSIONS;
@@ -84,12 +78,15 @@ public abstract class AbstractStringBasedModelInterpolator
 
     private final PathTranslator pathTranslator;
     private final UrlNormalizer urlNormalizer;
+    private final ModelVersionProcessor versionProcessor;
 
     @Inject
-    public AbstractStringBasedModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer )
+    public AbstractStringBasedModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer,
+                                                 ModelVersionProcessor processor )
     {
         this.pathTranslator = pathTranslator;
         this.urlNormalizer = urlNormalizer;
+        this.versionProcessor = processor;
     }
 
     protected List<ValueSource> createValueSources( final Model model, final File projectDir,
@@ -151,18 +148,8 @@ public abstract class AbstractStringBasedModelInterpolator
 
         // Overwrite existing values in model properties. Otherwise it's not possible
         // to define the version via command line: mvn -Drevision=6.5.7 ...
-        if ( config.getSystemProperties().containsKey( REVISION_PROPERTY ) )
+        versionProcessor.overwriteModelProperties( modelProperties, config );
-        {
+
-            modelProperties.put( REVISION_PROPERTY, config.getSystemProperties().get( REVISION_PROPERTY ) );
-        }
-        if ( config.getSystemProperties().containsKey( CHANGELIST_PROPERTY ) )
-        {
-            modelProperties.put( CHANGELIST_PROPERTY, config.getSystemProperties().get( CHANGELIST_PROPERTY ) );
-        }
-        if ( config.getSystemProperties().containsKey( SHA1_PROPERTY ) )
-        {
-            modelProperties.put( SHA1_PROPERTY, config.getSystemProperties().get( SHA1_PROPERTY ) );
-        }
         valueSources.add( new MapBasedValueSource( modelProperties ) );
 
         valueSources.add( new MapBasedValueSource( config.getSystemProperties() ) );

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

@@ -0,0 +1,69 @@
+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.Properties;
+
+import javax.inject.Named;
+import javax.inject.Singleton;
+
+import org.apache.maven.model.building.ModelBuildingRequest;
+
+/**
+ * Maven default implementation of the {@link ModelVersionProcessor} to support
+ * <a href="https://maven.apache.org/maven-ci-friendly.html">CI Friendly Versions</a>
+ */
+@Named
+@Singleton
+public class DefaultModelVersionProcessor
+    implements ModelVersionProcessor
+{
+
+    private static final String SHA1_PROPERTY = "sha1";
+
+    private static final String CHANGELIST_PROPERTY = "changelist";
+
+    private static final String REVISION_PROPERTY = "revision";
+
+    @Override
+    public boolean isValidProperty( String property )
+    {
+        return REVISION_PROPERTY.equals( property ) || CHANGELIST_PROPERTY.equals( property )
+            || SHA1_PROPERTY.equals( property );
+    }
+
+    @Override
+    public void overwriteModelProperties( Properties modelProperties, ModelBuildingRequest request )
+    {
+        if ( request.getSystemProperties().containsKey( REVISION_PROPERTY ) )
+        {
+            modelProperties.put( REVISION_PROPERTY, request.getSystemProperties().get( REVISION_PROPERTY ) );
+        }
+        if ( request.getSystemProperties().containsKey( CHANGELIST_PROPERTY ) )
+        {
+            modelProperties.put( CHANGELIST_PROPERTY, request.getSystemProperties().get( CHANGELIST_PROPERTY ) );
+        }
+        if ( request.getSystemProperties().containsKey( SHA1_PROPERTY ) )
+        {
+            modelProperties.put( SHA1_PROPERTY, request.getSystemProperties().get( SHA1_PROPERTY ) );
+        }
+
+    }
+}

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

@@ -0,0 +1,47 @@
+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.Properties;
+
+import org.apache.maven.model.building.ModelBuildingRequest;
+
+/**
+ * Allows a fixed set of properties that are valid inside a version and that could be overwritten for example on the
+ * commandline
+ */
+public interface ModelVersionProcessor
+{
+
+    /**
+     * @param property the property to check
+     * @return <code>true</code> if this is a valid property for this processor
+     */
+    boolean isValidProperty( String property );
+
+    /**
+     * This method is responsible for examining the request and possibly overwrite of the valid properties in the model
+     *
+     * @param modelProperties
+     * @param request
+     */
+    void overwriteModelProperties( Properties modelProperties, ModelBuildingRequest request );
+
+}

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

@@ -68,14 +68,10 @@ public class StringSearchModelInterpolator
     }
 
     @Inject
-    public StringSearchModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer )
+    public StringSearchModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer,
+                                          ModelVersionProcessor processor )
     {
-        super( pathTranslator, urlNormalizer );
+        super( pathTranslator, urlNormalizer, processor );
-    }
-
-    StringSearchModelInterpolator()
-    {
-        super( null, null );
     }
 
     @Override

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

@@ -92,9 +92,10 @@ public class StringVisitorModelInterpolator
     extends AbstractStringBasedModelInterpolator
 {
     @Inject
-    public StringVisitorModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer )
+    public StringVisitorModelInterpolator( PathTranslator pathTranslator, UrlNormalizer urlNormalizer,
+                                           ModelVersionProcessor processor )
     {
-        super( pathTranslator, urlNormalizer );
+        super( pathTranslator, urlNormalizer, processor );
     }
 
     interface InnerInterpolator

maven-model-builder/src/main/java/org/apache/maven/model/validation/DefaultModelValidator.java

@@ -44,7 +44,7 @@ import org.apache.maven.model.building.ModelProblem.Severity;
 import org.apache.maven.model.building.ModelProblem.Version;
 import org.apache.maven.model.building.ModelProblemCollector;
 import org.apache.maven.model.building.ModelProblemCollectorRequest;
-import org.apache.maven.model.interpolation.AbstractStringBasedModelInterpolator;
+import org.apache.maven.model.interpolation.ModelVersionProcessor;
 import org.codehaus.plexus.util.StringUtils;
 
 import java.io.File;
@@ -58,6 +58,7 @@ import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import javax.inject.Inject;
 import javax.inject.Named;
 import javax.inject.Singleton;
 
@@ -72,11 +73,6 @@ public class DefaultModelValidator
 
     private static final Pattern EXPRESSION_NAME_PATTERN = Pattern.compile( "\\$\\{(.+?)\\}" );
 
-    private static final List<String> CI_FRIENDLY_POSSIBLE_PROPERTY_NAMES =
-        Arrays.asList( AbstractStringBasedModelInterpolator.REVISION_PROPERTY,
-                       AbstractStringBasedModelInterpolator.CHANGELIST_PROPERTY,
-                       AbstractStringBasedModelInterpolator.SHA1_PROPERTY );
-
     private static final String ILLEGAL_FS_CHARS = "\\/:\"<>|?*";
 
     private static final String ILLEGAL_VERSION_CHARS = ILLEGAL_FS_CHARS;
@@ -89,6 +85,14 @@ public class DefaultModelValidator
 
     private final Set<String> validProfileIds = new HashSet<>();
 
+    private final ModelVersionProcessor versionProcessor;
+
+    @Inject
+    public DefaultModelValidator( ModelVersionProcessor versionProcessor )
+    {
+        this.versionProcessor = versionProcessor;
+    }
+
     @Override
     public void validateFileModel( Model m, ModelBuildingRequest request, ModelProblemCollector problems )
     {
@@ -998,17 +1002,11 @@ public class DefaultModelValidator
             return true;
         }
 
-        //
-        // Acceptable versions for continuous delivery
-        //
-        // changelist
-        // revision
-        // sha1
-        //
         Matcher m = EXPRESSION_NAME_PATTERN.matcher( string.trim() );
         while ( m.find() )
         {
-            if ( !CI_FRIENDLY_POSSIBLE_PROPERTY_NAMES.contains( m.group( 1 ) ) )
+            String property = m.group( 1 );
+            if ( !versionProcessor.isValidProperty( property ) )
             {
                 addViolation( problems, severity, version, fieldName, null,
                               "contains an expression but should be a constant.", tracker );

maven-model-builder/src/test/java/org/apache/maven/model/interpolation/StringSearchModelInterpolatorTest.java

@@ -58,7 +58,7 @@ public class StringSearchModelInterpolatorTest
 {
     protected ModelInterpolator createInterpolator()
     {
-        return new StringSearchModelInterpolator();
+        return new StringSearchModelInterpolator( null, null, new DefaultModelVersionProcessor() );
     }
 
     @Test
@@ -579,7 +579,8 @@ public class StringSearchModelInterpolatorTest
         request.setUserProperties( props );
 
         SimpleProblemCollector problems = new SimpleProblemCollector();
-        StringSearchModelInterpolator interpolator = new StringSearchModelInterpolator();
+        StringSearchModelInterpolator interpolator =
+            new StringSearchModelInterpolator( null, null, new DefaultModelVersionProcessor() );
         interpolator.interpolateObject( new ClassWithFinalField(), new Model(), null, request, problems );
 
         assertProblemFree( problems );
@@ -605,7 +606,8 @@ public class StringSearchModelInterpolatorTest
         model.setLocation( "", new InputLocation( 1, 1, source ) );
 
         SimpleProblemCollector problems = new SimpleProblemCollector();
-        StringSearchModelInterpolator interpolator = new StringSearchModelInterpolator();
+        StringSearchModelInterpolator interpolator =
+            new StringSearchModelInterpolator( null, null, new DefaultModelVersionProcessor() );
         interpolator.interpolateObject( model, model, null, request, problems );
 
         assertProblemFree( problems );

maven-model-builder/src/test/java/org/apache/maven/model/interpolation/StringVisitorModelInterpolatorTest.java

@@ -23,6 +23,6 @@ public class StringVisitorModelInterpolatorTest extends AbstractModelInterpolato
 {
     protected ModelInterpolator createInterpolator()
     {
-        return new StringVisitorModelInterpolator( null, null );
+        return new StringVisitorModelInterpolator( null, null, new DefaultModelVersionProcessor() );
     }
 }

maven-model-builder/src/test/java/org/apache/maven/model/validation/DefaultModelValidatorTest.java

@@ -26,6 +26,7 @@ import org.apache.maven.model.Model;
 import org.apache.maven.model.building.DefaultModelBuildingRequest;
 import org.apache.maven.model.building.ModelBuildingRequest;
 import org.apache.maven.model.building.SimpleProblemCollector;
+import org.apache.maven.model.interpolation.DefaultModelVersionProcessor;
 import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -103,7 +104,7 @@ public class DefaultModelValidatorTest
     public void setUp()
         throws Exception
     {
-        validator = new DefaultModelValidator();
+        validator = new DefaultModelValidator( new DefaultModelVersionProcessor() );
     }
 
     @AfterEach