Add 'skip' configuration option.

README.md

@@ -177,6 +177,13 @@ It's really simple to setup this plugin; below is a sample pom that you may base
                         -->
                         <forceLongFormat>false</forceLongFormat>
                     </gitDescribe>
+
+                    <!-- @since 2.1.8 -->
+                    <!--
+                        skip the plugin execution completely. This is useful for e.g. profile activated plugin invocations or
+                        to use properties to enable / disable pom features. Default value is 'false'.
+                    -->
+                    <skip>false</skip>
                 </configuration>
 
             </plugin>
@@ -482,6 +489,7 @@ Optional parameters:
 * **generateGitPropertiesFilename** - `(default: src/main/resources/git.properties)` - The path for the to be generated properties file, it's relative to ${project.basedir}
 * **skipPoms** - `(default: true)` - Force the plugin to run even if you're inside of an pom packaged project.
 * **failOnNoGitDirectory** - `(default: true)` *(available since v2.0.4)* - Specify whether the plugin should fail when a .git directory can not be found. When set to false and no .git directory is found the plugin will skip execution.
+* **skip** - `(default: false)` *(available since v2.1.8)* - Skip the plugin execution completely.
 
 **gitDescribe**:
 Worth pointing out is, that git-commit-id tries to be 1-to-1 compatible with git's plain output, even though the describe functionality has been reimplemented manually using JGit (you don't have to have a git executable to use the plugin). So if you're familiar with [git-describe](https://github.com/ktoso/maven-git-commit-id-plugin#git-describe---short-intro-to-an-awesome-command), you probably can skip this section, as it just explains the same options that git provides.

src/main/java/pl/project13/maven/git/GitCommitIdMojo.java

@@ -239,6 +239,15 @@ public class GitCommitIdMojo extends AbstractMojo {
   @SuppressWarnings("UnusedDeclaration")
   private boolean failOnUnableToExtractRepoInfo;
 
+  /**
+   * Skip the plugin execution.
+   *
+   * @parameter default-value="false"
+   * @since 2.1.8
+   */
+  @SuppressWarnings("UnusedDeclaration")
+  private boolean skip = false;
+
   /**
    * The properties we store our data in and then expose them
    */
@@ -253,6 +262,11 @@ public void execute() throws MojoExecutionException {
     // Set the verbose setting now it should be correctly loaded from maven.
     loggerBridge.setVerbose(verbose);
 
+    if (skip) {
+      log("skip is true, return");
+      return;
+    }
+
     if (isPomProject(project) && skipPoms) {
       log("isPomProject is true and skipPoms is true, return");
       return;

src/test/java/pl/project13/maven/git/GitCommitIdMojoIntegrationTest.java

@@ -52,6 +52,21 @@ public void shouldResolvePropertiesOnDefaultSettingsForNonPomProject() throws Ex
     assertGitPropertiesPresentInProject(targetProject.getProperties());
   }
 
+  @Test
+  public void shouldNotRunWhenSkipIsSet() throws Exception {
+    // given
+        mavenSandbox.withParentProject("my-skip-project", "jar").withNoChildProject().withGitRepoInParent(AvailableGitTestRepo.WITH_ONE_COMMIT).create(CleanUp.CLEANUP_FIRST);
+    MavenProject targetProject = mavenSandbox.getParentProject();
+    setProjectToExecuteMojoIn(targetProject);
+    alterMojoSettings("skip", Boolean.TRUE);
+
+    // when
+    mojo.execute();
+
+    // then
+    assertThat(targetProject.getProperties()).isEmpty();
+  }
+
   @Test
   public void shouldNotRunWhenPackagingPomAndDefaultSettingsApply() throws Exception {
     // given
@@ -111,6 +126,7 @@ public void shouldUseChildProjectRepoIfInvokedFromChild() throws Exception {
     assertGitPropertiesPresentInProject(targetProject.getProperties());
   }
 
+  @Test
   public void shouldFailWithExceptionWhenNoGitRepoFound() throws Exception {
     // given
     mavenSandbox.withParentProject("my-pom-project", "pom")
@@ -196,6 +212,44 @@ public void shouldGenerateCustomPropertiesFileJson() throws Exception {
       }
   }
 
+  @Test
+  public void shouldSkipWithoutFailOnNoGitDirectoryWhenNoGitRepoFound() throws Exception {
+    // given
+    mavenSandbox.withParentProject("my-jar-project", "jar")
+                .withNoChildProject()
+                .withNoGitRepoAvailable()
+                .create(CleanUp.CLEANUP_FIRST);
+
+    MavenProject targetProject = mavenSandbox.getParentProject();
+    setProjectToExecuteMojoIn(targetProject);
+    alterMojoSettings("failOnNoGitDirectory", false);
+
+    // when
+    mojo.execute();
+
+    // then
+    assertThat(targetProject.getProperties()).isEmpty();
+  }
+
+  @Test
+  public void shouldNotSkipWithoutFailOnNoGitDirectoryWhenNoGitRepoIsPresent() throws Exception {
+    // given
+    mavenSandbox.withParentProject("my-jar-project", "jar")
+                .withNoChildProject()
+                .withGitRepoInParent(AvailableGitTestRepo.WITH_ONE_COMMIT)
+                .create(CleanUp.CLEANUP_FIRST);
+
+    MavenProject targetProject = mavenSandbox.getParentProject();
+    setProjectToExecuteMojoIn(targetProject);
+    alterMojoSettings("failOnNoGitDirectory", false);
+
+    // when
+    mojo.execute();
+
+    // then
+    assertGitPropertiesPresentInProject(targetProject.getProperties());
+  }
+
   private void alterMojoSettings(String parameterName, Object parameterValue) {
     setInternalState(mojo, parameterName, parameterValue);
   }