make write-*-properties output reproducible: sort & drop timestamp

.gitignore

@@ -4,3 +4,4 @@ target
 .classpath
 *.iml
 /.idea/
+/.factorypath

pom.xml

@@ -142,4 +142,43 @@
 
   </dependencies>
 
+  <profiles>
+    <profile>
+      <id>run-its</id>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-invoker-plugin</artifactId>
+            <configuration>
+              <addTestClassPath>true</addTestClassPath>
+              <debug>true</debug>
+              <localRepositoryPath>${project.build.directory}/local-repo</localRepositoryPath>
+              <cloneProjectsTo>${project.build.directory}/it</cloneProjectsTo>
+              <projectsDirectory>src/it</projectsDirectory>
+              <showVersion>true</showVersion>
+              <setupIncludes>
+                <setupInclude>setup/pom.xml</setupInclude>
+              </setupIncludes>
+              <pomIncludes>
+                <pomInclude>*/pom.xml</pomInclude>
+              </pomIncludes>
+              <preBuildHookScript>setup</preBuildHookScript>
+              <postBuildHookScript>verify</postBuildHookScript>
+              <settingsFile>src/it/settings.xml</settingsFile>
+            </configuration>
+            <executions>
+              <execution>
+                <goals>
+                  <goal>install</goal>
+                  <goal>integration-test</goal>
+                  <goal>verify</goal>
+                </goals>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+  </profiles>
 </project>

src/it/settings.xml

@@ -0,0 +1,63 @@
+<?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.
+-->
+
+<settings>
+ <mirrors>
+    <mirror>
+      <id>it-repo</id>
+      <name>RPM</name>
+      <url>@localRepositoryUrl@</url>
+      <mirrorOf>*</mirrorOf>
+    </mirror>
+  </mirrors>
+  <profiles>
+    <profile>
+      <id>it-repo</id>
+      <activation>
+        <activeByDefault>true</activeByDefault>
+      </activation>
+      <repositories>
+        <repository>
+          <id>local.central</id>
+          <url>@localRepositoryUrl@</url>
+          <releases>
+            <enabled>true</enabled>
+          </releases>
+          <snapshots>
+            <enabled>true</enabled>
+          </snapshots>
+        </repository>
+      </repositories>
+      <pluginRepositories>
+        <pluginRepository>
+          <id>local.central</id>
+          <url>@localRepositoryUrl@</url>
+          <releases>
+            <enabled>true</enabled>
+          </releases>
+          <snapshots>
+            <enabled>true</enabled>
+          </snapshots>
+        </pluginRepository>
+      </pluginRepositories>
+    </profile>
+  </profiles>
+</settings>

src/it/write-project/invoker.properties

@@ -0,0 +1 @@
+invoker.goals = clean generate-resources

src/it/write-project/pom.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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.codehaus.mojo.properties.it</groupId>
+  <artifactId>write-project</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+
+  <properties>
+    <g>${groupId}</g>
+    <a>${artifactId}</a>
+    <v>${version}</v>
+    <properties-maven-plugin.version>@project.version@</properties-maven-plugin.version>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>properties-maven-plugin</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <phase>generate-resources</phase>
+            <goals>
+              <goal>write-project-properties</goal>
+            </goals>
+            <configuration>
+              <outputFile>${project.build.outputDirectory}/project.properties</outputFile>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/write-project/verify.groovy

@@ -0,0 +1,24 @@
+/*
+ * 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.
+ */
+File prop = new File( basedir, 'target/classes/project.properties' )
+assert prop.exists()
+
+String content = prop.getText()
+assert content.startsWith( "#Properties" )
+assert !content.substring( 1 ).contains( '#' ) // check no timestamp comment, that starts with #

src/main/java/org/codehaus/mojo/properties/AbstractWritePropertiesMojo.java

@@ -1,5 +1,7 @@
 package org.codehaus.mojo.properties;
 
+import java.io.BufferedReader;
+
 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
@@ -23,6 +25,13 @@
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Properties;
 
 /*
@@ -70,9 +79,9 @@ public abstract class AbstractWritePropertiesMojo
     protected void writeProperties( Properties properties, File file )
         throws MojoExecutionException
     {
-        try ( FileOutputStream fos = new FileOutputStream( file ) )
+        try
         {
-            properties.store( fos, "Properties" );
+            storeWithoutTimestamp( properties, file, "Properties" );
         }
         catch ( FileNotFoundException e )
         {
@@ -86,6 +95,36 @@ protected void writeProperties( Properties properties, File file )
         }
     }
 
+    // https://github.com/apache/maven-archiver/blob/master/src/main/java/org/apache/maven/archiver/PomPropertiesUtil.java#L81
+    private void storeWithoutTimestamp( Properties properties, File outputFile, String comments )
+        throws IOException
+    {
+        try ( PrintWriter pw = new PrintWriter( outputFile, "ISO-8859-1" ); StringWriter sw = new StringWriter() )
+        {
+            properties.store( sw, comments );
+            comments = '#' + comments;
+
+            List<String> lines = new ArrayList<>();
+            try ( BufferedReader r = new BufferedReader( new StringReader( sw.toString() ) ) )
+            {
+                String line;
+                while ( ( line = r.readLine() ) != null )
+                {
+                    if ( !line.startsWith( "#" ) || line.equals( comments ) )
+                    {
+                        lines.add( line );
+                    }
+                }
+            }
+
+            Collections.sort( lines );
+            for ( String l : lines )
+            {
+                pw.println( l );
+            }
+        }
+    }
+
     /**
      * @throws MojoExecutionException {@link MojoExecutionException}
      */

src/main/java/org/codehaus/mojo/properties/WriteProjectProperties.java

@@ -43,7 +43,6 @@
 import java.util.Properties;
 
 import org.apache.maven.plugin.MojoExecutionException;
-import org.apache.maven.plugin.MojoFailureException;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;