[MCHECKSTYLE-412] Add option to exclude generated sources/test-source…

…s from default source/test-source directories

This closes #76

src/it/MCHECKSTYLE-412/invoker.properties

@@ -0,0 +1,18 @@
+# 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.
+
+invoker.goals=verify

src/it/MCHECKSTYLE-412/pom.xml

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ 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.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.plugins.checkstyle.its</groupId>
+  <artifactId>MCHECKSTYLE-412</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <url>https://issues.apache.org/jira/browse/MCHECKSTYLE-412</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.antlr</groupId>
+      <artifactId>antlr4</artifactId>
+      <version>4.3</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.antlr</groupId>
+        <artifactId>antlr4-maven-plugin</artifactId>
+        <version>4.3</version>
+        <executions>
+          <execution>
+            <id>antlr</id>
+            <goals>
+              <goal>antlr4</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <version>@project.version@</version>
+        <configuration>
+          <excludeGeneratedSources>true</excludeGeneratedSources>
+        </configuration>
+        <executions>
+          <execution>
+            <id>check</id>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/MCHECKSTYLE-412/src/main/antlr4/MyGrammar.g4

@@ -0,0 +1,21 @@
+// 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.
+
+grammar MyGrammar;
+r  : 'foo' ID ;
+ID : [a-zA-Z0-9_]+ ;
+WS : [ \t\r\n]+ -> skip ;

src/it/MCHECKSTYLE-412/src/main/java/org/MyClass.java

@@ -0,0 +1,26 @@
+package org;
+
+/*
+ * 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.
+ */
+
+/**
+ * My class.
+ */
+public class MyClass {
+}

src/it/MCHECKSTYLE-412/src/main/java/org/package-info.java

@@ -0,0 +1,23 @@
+/**
+ * Nothing very important here, only a file for checkstyle rule PackageInfo.
+ */
+package org;
+
+/*
+ * 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.
+ */

src/it/MCHECKSTYLE-412/verify.groovy

@@ -0,0 +1,22 @@
+
+/*
+ * 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.
+ */
+def buildLog = new File( basedir, 'build.log' )
+
+assert buildLog.text.contains( "[INFO] You have 0 Checkstyle violations." )

src/main/java/org/apache/maven/plugins/checkstyle/AbstractCheckstyleReport.java

@@ -24,6 +24,7 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -426,6 +427,14 @@ public abstract class AbstractCheckstyleReport extends AbstractMavenReport {
                     + "        \"https://checkstyle.org/dtds/configuration_1_3.dtd\">\n")
     private String checkstyleRulesHeader;
 
+    /**
+     * Specifies whether generated source files should be excluded from Checkstyle.
+     *
+     * @since 3.3.1
+     */
+    @Parameter(property = "checkstyle.excludeGeneratedSources", defaultValue = "false")
+    private boolean excludeGeneratedSources;
+
     /**
      */
     @Component
@@ -697,7 +706,7 @@ private boolean checkMavenJxrPluginIsConfigured() {
 
     protected List<File> getSourceDirectories() {
         if (sourceDirectories == null) {
-            sourceDirectories = project.getCompileSourceRoots();
+            sourceDirectories = filterBuildTarget(project.getCompileSourceRoots());
         }
         List<File> sourceDirs = new ArrayList<>(sourceDirectories.size());
         for (String sourceDir : sourceDirectories) {
@@ -708,12 +717,31 @@ protected List<File> getSourceDirectories() {
 
     protected List<File> getTestSourceDirectories() {
         if (testSourceDirectories == null) {
-            testSourceDirectories = project.getTestCompileSourceRoots();
+            testSourceDirectories = filterBuildTarget(project.getTestCompileSourceRoots());
         }
         List<File> testSourceDirs = new ArrayList<>(testSourceDirectories.size());
         for (String testSourceDir : testSourceDirectories) {
             testSourceDirs.add(FileUtils.resolveFile(project.getBasedir(), testSourceDir));
         }
         return testSourceDirs;
     }
+
+    private List<String> filterBuildTarget(List<String> sourceDirectories) {
+        if (!excludeGeneratedSources) {
+            return sourceDirectories;
+        }
+
+        List<String> filtered = new ArrayList<>(sourceDirectories.size());
+        Path buildTarget = FileUtils.resolveFile(
+                        project.getBasedir(), project.getBuild().getDirectory())
+                .toPath();
+
+        for (String sourceDir : sourceDirectories) {
+            Path src = FileUtils.resolveFile(project.getBasedir(), sourceDir).toPath();
+            if (!src.startsWith(buildTarget)) {
+                filtered.add(sourceDir);
+            }
+        }
+        return filtered;
+    }
 }

src/main/java/org/apache/maven/plugins/checkstyle/CheckstyleViolationCheckMojo.java

@@ -27,6 +27,7 @@
 import java.io.OutputStream;
 import java.io.Reader;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -476,6 +477,14 @@ public class CheckstyleViolationCheckMojo extends AbstractMojo {
     @Parameter(defaultValue = "false")
     private boolean omitIgnoredModules;
 
+    /**
+     * Specifies whether generated source files should be excluded from Checkstyle.
+     *
+     * @since 3.3.1
+     */
+    @Parameter(property = "checkstyle.excludeGeneratedSources", defaultValue = "false")
+    private boolean excludeGeneratedSources;
+
     private ByteArrayOutputStream stringOutputStream;
 
     private File outputXmlFile;
@@ -832,7 +841,7 @@ private List<Artifact> getCheckstylePluginDependenciesAsArtifacts(Map<String, Pl
 
     private List<File> getSourceDirectories() {
         if (sourceDirectories == null) {
-            sourceDirectories = project.getCompileSourceRoots();
+            sourceDirectories = filterBuildTarget(project.getCompileSourceRoots());
         }
         List<File> sourceDirs = new ArrayList<>(sourceDirectories.size());
         for (String sourceDir : sourceDirectories) {
@@ -843,12 +852,31 @@ private List<File> getSourceDirectories() {
 
     private List<File> getTestSourceDirectories() {
         if (testSourceDirectories == null) {
-            testSourceDirectories = project.getTestCompileSourceRoots();
+            testSourceDirectories = filterBuildTarget(project.getTestCompileSourceRoots());
         }
         List<File> testSourceDirs = new ArrayList<>(testSourceDirectories.size());
         for (String testSourceDir : testSourceDirectories) {
             testSourceDirs.add(FileUtils.resolveFile(project.getBasedir(), testSourceDir));
         }
         return testSourceDirs;
     }
+
+    private List<String> filterBuildTarget(List<String> sourceDirectories) {
+        if (!excludeGeneratedSources) {
+            return sourceDirectories;
+        }
+
+        List<String> filtered = new ArrayList<>(sourceDirectories.size());
+        Path buildTarget = FileUtils.resolveFile(
+                        project.getBasedir(), project.getBuild().getDirectory())
+                .toPath();
+
+        for (String sourceDir : sourceDirectories) {
+            Path src = FileUtils.resolveFile(project.getBasedir(), sourceDir).toPath();
+            if (!src.startsWith(buildTarget)) {
+                filtered.add(sourceDir);
+            }
+        }
+        return filtered;
+    }
 }