#568 introduce updateBuildOutputTimestamp property to make it configurable whether project.build.outputTimestamp is updated or not

src/it/it-set-020-outputTimestamp-disabled/invoker.properties

@@ -0,0 +1 @@
+invoker.goals=${project.groupId}:${project.artifactId}:${project.version}:set -DnewVersion=2.0 -DupdateBuildOutputTimestamp=false

src/it/it-set-020-outputTimestamp-disabled/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-020-outputTimestamp-disabled</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-020-outputTimestamp-disabled/verify.groovy

@@ -0,0 +1,4 @@
+pom = new File( basedir, "pom.xml" ).text;
+
+// expect outputTimestamp to be untouched
+assert pom =~ /<project.build.outputTimestamp>10<.project.build.outputTimestamp>/

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

@@ -202,6 +202,14 @@ public class SetMojo
     @Parameter( property = "processFromLocalAggregationRoot", defaultValue = "true" )
     private boolean processFromLocalAggregationRoot;
 
+    /**
+     * Whether to update the <code>project.build.outputTimestamp<code> property in the POM when setting version.
+     *
+     * @since 2.10
+     */
+    @Parameter( property = "updateBuildOutputTimestamp", defaultValue = "true" )
+    private boolean updateBuildOutputTimestamp;
+
     /**
      * The changes to module coordinates. Guarded by this.
      */
@@ -506,8 +514,10 @@ protected synchronized void update( ModifiedPomXMLEventReader pom )
             {
                 changer.apply( versionChange );
 
-                // also update project.build.outputTimestamp
-                updateBuildOutputTimestamp( pom, model );
+                if (updateBuildOutputTimestamp) {
+                    // also update project.build.outputTimestamp
+                    updateBuildOutputTimestamp( pom, model );
+                }
             }
         }
         catch ( IOException e )