New property: updateBuildOutputTimestampPolicy = (onchange | always | never) (#595)

src/it/it-set-021-outputTimestampPolicy-always/invoker.properties

@@ -0,0 +1 @@
+invoker.goals=${project.groupId}:${project.artifactId}:${project.version}:set -DnewVersion=1.0 -DupdateBuildOutputTimestampPolicy=always

src/it/it-set-021-outputTimestampPolicy-always/pom.xml

@@ -0,0 +1,14 @@
+<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>localhost</groupId>
+  <artifactId>it-set-021-outputTimestampPolicy-always</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set</name>
+
+  <properties>
+    <project.build.outputTimestamp>10</project.build.outputTimestamp>
+  </properties>
+</project>

src/it/it-set-021-outputTimestampPolicy-always/verify.groovy

@@ -0,0 +1,3 @@
+pom = new File( basedir, "pom.xml" ).text
+
+assert pom =~ /<project.build.outputTimestamp>\d\d\d\d+<.project.build.outputTimestamp>/

src/it/it-set-022-outputTimestampPolicy-onchange/invoker.properties

@@ -0,0 +1 @@
+invoker.goals=${project.groupId}:${project.artifactId}:${project.version}:set -DnewVersion=1.0 -DupdateBuildOutputTimestampPolicy=onchange

src/it/it-set-022-outputTimestampPolicy-onchange/pom.xml

@@ -0,0 +1,14 @@
+<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>localhost</groupId>
+  <artifactId>it-set-022-outputTimestampPolicy-onchange</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set</name>
+
+  <properties>
+    <project.build.outputTimestamp>10</project.build.outputTimestamp>
+  </properties>
+</project>

src/it/it-set-022-outputTimestampPolicy-onchange/verify.groovy

@@ -0,0 +1,3 @@
+pom = new File( basedir, "pom.xml" ).text
+
+assert pom =~ /<project.build.outputTimestamp>10<.project.build.outputTimestamp>/

src/it/it-set-023-outputTimestampPolicy-never/invoker.properties

@@ -0,0 +1 @@
+invoker.goals=${project.groupId}:${project.artifactId}:${project.version}:set -DnewVersion=2.0 -DupdateBuildOutputTimestampPolicy=never

src/it/it-set-023-outputTimestampPolicy-never/pom.xml

@@ -0,0 +1,14 @@
+<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>localhost</groupId>
+  <artifactId>it-set-023-outputTimestampPolicy-never</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set</name>
+
+  <properties>
+    <project.build.outputTimestamp>10</project.build.outputTimestamp>
+  </properties>
+</project>

src/it/it-set-023-outputTimestampPolicy-never/verify.groovy

@@ -0,0 +1,3 @@
+pom = new File( basedir, "pom.xml" ).text
+
+assert pom =~ /<project.build.outputTimestamp>10<.project.build.outputTimestamp>/

src/main/java/org/codehaus/mojo/versions/SetMojo.java

@@ -84,7 +84,7 @@ public class SetMojo
 
     /**
      * The groupId of the dependency/module to update.
-     * If you like to update modules of a aggregator you 
+     * If you like to update modules of a aggregator you
      * should set <code>-DgroupId='*'</code> to ignore the
      * group of the current project. On Windows you can omit
      * the single quotes on Linux they are necessary to prevent
@@ -97,7 +97,7 @@ public class SetMojo
 
     /**
      * The artifactId of the dependency/module to update.
-     * If you like to update modules of a aggregator you 
+     * If you like to update modules of a aggregator you
      * should set <code>-DartifactId='*'</code> to ignore the
      * artifactId of the current project. On Windows you can omit
      * the single quotes on Linux they are necessary to prevent
@@ -204,12 +204,21 @@ public class SetMojo
 
     /**
      * Whether to update the <code>project.build.outputTimestamp<code> property in the POM when setting version.
+     * Deprecated; please use <code>updateBuildOutputTimestampPolicy</code> instead.
      *
      * @since 2.10
      */
     @Parameter( property = "updateBuildOutputTimestamp", defaultValue = "true" )
     private boolean updateBuildOutputTimestamp;
 
+    /**
+     * Whether to update the <code>project.build.outputTimestamp<code> property in the POM when setting version.
+     *
+     * @since 2.12
+     */
+    @Parameter( property = "updateBuildOutputTimestampPolicy", defaultValue = "onchange" )
+    private String updateBuildOutputTimestampPolicy;
+
     /**
      * The changes to module coordinates. Guarded by this.
      */
@@ -301,6 +310,14 @@ public void execute()
                 + "property (that is -DnewVersion=... on the command line) or run in interactive mode" );
         }
 
+        if ( !"onchange".equals( updateBuildOutputTimestampPolicy )
+                && !"always".equals( updateBuildOutputTimestampPolicy )
+                && !"never".equals( updateBuildOutputTimestampPolicy ) )
+        {
+            throw new MojoExecutionException( "updateBuildOutputTimestampPolicy should be one of: "
+                    + "\"onchange\", \"always\", \"never\"." );
+        }
+
         try
         {
             final MavenProject project;
@@ -513,10 +530,12 @@ protected synchronized void update( ModifiedPomXMLEventReader pom )
             for ( VersionChange versionChange : sourceChanges )
             {
                 changer.apply( versionChange );
+            }
 
-                if (updateBuildOutputTimestamp) {
+            if ( updateBuildOutputTimestamp && !"never".equals( updateBuildOutputTimestampPolicy ) ) {
+                if ( "always".equals( updateBuildOutputTimestampPolicy) || !sourceChanges.isEmpty() ) {
                     // also update project.build.outputTimestamp
-                    updateBuildOutputTimestamp( pom, model );
+                    updateBuildOutputTimestamp(pom, model);
                 }
             }
         }