[MJAR-296] Allow including files excluded by default.

src/it/MJAR-296/pom.xml

@@ -0,0 +1,49 @@
+<?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/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.plugins</groupId>
+  <artifactId>mjar-296-suppress-default-excludes</artifactId>
+  <name>mjar-296-suppress-default-excludes</name>
+  <description>Verifies that the resulting jar includes files excluded by default</description>
+  <packaging>jar</packaging>
+  <version>1.0-SNAPSHOT</version>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <project.build.outputTimestamp>2023-11-19T13:25:58Z</project.build.outputTimestamp>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>@project.version@</version>
+        <configuration>
+          <addDefaultExcludes>false</addDefaultExcludes>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/MJAR-296/src/main/java/Foo.java

@@ -0,0 +1,31 @@
+
+/*
+ * 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.
+ */
+
+/**
+ * Hello world!
+ *
+ */
+public class Foo
+{
+    public static void main( String[] args )
+    {
+        System.out.println( "Hello World!" );
+    }
+}

src/it/MJAR-296/src/main/resources/.gitignore

@@ -0,0 +1 @@
+# By default the file is excluded

src/it/MJAR-296/verify.groovy

@@ -0,0 +1,58 @@
+
+/*
+ * 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.jar.*;
+
+boolean result = false;
+
+try
+{
+    File target = new File( basedir, "target" )
+    if ( !target.exists() || !target.isDirectory() ) {
+        System.err.println( "target file is missing or not a directory." )
+        return result
+    }
+
+    File artifact = new File( target, "mjar-296-suppress-default-excludes-1.0-SNAPSHOT.jar" )
+    if ( !artifact.exists() || artifact.isDirectory() ) {
+        System.err.println( "artifact file is missing or a directory." )
+        return result
+    }
+
+    String expectedFileName = ".gitignore"
+
+    JarFile jar = new JarFile( artifact )
+    Enumeration jarEntries = jar.entries()
+    while ( jarEntries.hasMoreElements() ) {
+        JarEntry entry = (JarEntry) jarEntries.nextElement();
+        if ( !entry.isDirectory() && expectedFileName.equals(entry.getName()) ) {
+            result = true
+        }
+    }
+
+    if ( !result ) {
+        System.err.println( "Expected file[" + expectedFileName + "] not found in the jar archive." )
+    }
+} catch( Throwable e ) {
+    e.printStackTrace()
+    result = false
+}
+
+return result

src/main/java/org/apache/maven/plugins/jar/AbstractJarMojo.java

@@ -36,6 +36,7 @@
 import org.apache.maven.shared.model.fileset.util.FileSetManager;
 import org.codehaus.plexus.archiver.Archiver;
 import org.codehaus.plexus.archiver.jar.JarArchiver;
+import org.codehaus.plexus.archiver.util.DefaultFileSet;
 
 /**
  * Base class for creating a jar from project classes.
@@ -161,6 +162,36 @@ public abstract class AbstractJarMojo extends AbstractMojo {
     @Parameter(property = "maven.jar.detectMultiReleaseJar", defaultValue = "true")
     private boolean detectMultiReleaseJar;
 
+    /**
+     * If set to {@code false}, the files that by default are excluded from the resulting archive,
+     * like {@code .gitignore}, {@code .cvsignore} etc. will be included.
+     * This means all files like the following will be included.
+     * <ul>
+     * <li>Misc: &#42;&#42;/&#42;~, &#42;&#42;/#&#42;#, &#42;&#42;/.#&#42;, &#42;&#42;/%&#42;%, &#42;&#42;/._&#42;</li>
+     * <li>CVS: &#42;&#42;/CVS, &#42;&#42;/CVS/&#42;&#42;, &#42;&#42;/.cvsignore</li>
+     * <li>RCS: &#42;&#42;/RCS, &#42;&#42;/RCS/&#42;&#42;</li>
+     * <li>SCCS: &#42;&#42;/SCCS, &#42;&#42;/SCCS/&#42;&#42;</li>
+     * <li>VSSercer: &#42;&#42;/vssver.scc</li>
+     * <li>MKS: &#42;&#42;/project.pj</li>
+     * <li>SVN: &#42;&#42;/.svn, &#42;&#42;/.svn/&#42;&#42;</li>
+     * <li>GNU: &#42;&#42;/.arch-ids, &#42;&#42;/.arch-ids/&#42;&#42;</li>
+     * <li>Bazaar: &#42;&#42;/.bzr, &#42;&#42;/.bzr/&#42;&#42;</li>
+     * <li>SurroundSCM: &#42;&#42;/.MySCMServerInfo</li>
+     * <li>Mac: &#42;&#42;/.DS_Store</li>
+     * <li>Serena Dimension: &#42;&#42;/.metadata, &#42;&#42;/.metadata/&#42;&#42;</li>
+     * <li>Mercurial: &#42;&#42;/.hg, &#42;&#42;/.hg/&#42;&#42;</li>
+     * <li>Git: &#42;&#42;/.git, &#42;&#42;/.git/&#42;&#42;</li>
+     * <li>Bitkeeper: &#42;&#42;/BitKeeper, &#42;&#42;/BitKeeper/&#42;&#42;, &#42;&#42;/ChangeSet,
+     * &#42;&#42;/ChangeSet/&#42;&#42;</li>
+     * <li>Darcs: &#42;&#42;/_darcs, &#42;&#42;/_darcs/&#42;&#42;, &#42;&#42;/.darcsrepo,
+     * &#42;&#42;/.darcsrepo/&#42;&#42;&#42;&#42;/-darcs-backup&#42;, &#42;&#42;/.darcs-temp-mail
+     * </ul>
+     *
+     * @since 3.4.0
+     */
+    @Parameter(defaultValue = "true")
+    private boolean addDefaultExcludes;
+
     /**
      * Return the specific output directory to serve as the root for the archive.
      * @return get classes directory.
@@ -222,6 +253,7 @@ public File createArchive() throws MojoExecutionException {
         jarContentFileSet.setDirectory(getClassesDirectory().getAbsolutePath());
         jarContentFileSet.setIncludes(Arrays.asList(getIncludes()));
         jarContentFileSet.setExcludes(Arrays.asList(getExcludes()));
+        jarContentFileSet.setUseDefaultExcludes(addDefaultExcludes);
 
         String[] includedFiles = fileSetManager.getIncludedFiles(jarContentFileSet);
 
@@ -262,7 +294,7 @@ public File createArchive() throws MojoExecutionException {
                     getLog().warn("JAR will be empty - no content was marked for inclusion!");
                 }
             } else {
-                archiver.getArchiver().addDirectory(contentDirectory, getIncludes(), getExcludes());
+                archiver.getArchiver().addFileSet(getFileSet(contentDirectory));
             }
 
             archiver.createArchive(session, project, archive);
@@ -334,4 +366,13 @@ private String[] getExcludes() {
         }
         return DEFAULT_EXCLUDES;
     }
+
+    private org.codehaus.plexus.archiver.FileSet getFileSet(File contentDirectory) {
+        DefaultFileSet fileSet = DefaultFileSet.fileSet(contentDirectory)
+                .includeExclude(getIncludes(), getExcludes())
+                .includeEmptyDirs(true);
+
+        fileSet.setUsingDefaultExcludes(false);
+        return fileSet;
+    }
 }