Add Mojo for setting the SCM tag

Closes mojohaus#182

pom.xml

@@ -73,6 +73,11 @@
     <contributor>
       <name>Erik Schepers</name>
     </contributor>
+    <contributor>
+      <name>Anton Johansson</name>
+      <email>antoon.johansson@gmail.com</email>
+      <timezone>+1</timezone>
+    </contributor>
   </contributors>
 
   <prerequisites>

src/it/it-set-scm-tag-001/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals.1=${project.groupId}:${project.artifactId}:${project.version}:set-scm-tag -DnewTag=v1.0
+invoker.buildResult.1=success

src/it/it-set-scm-tag-001/pom.xml

@@ -0,0 +1,13 @@
+<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-scm-tag-001</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set-scm-tag</name>
+  <scm>
+    <tag>HEAD</tag>
+  </scm>
+</project>

src/it/it-set-scm-tag-001/verify.bsh

@@ -0,0 +1,32 @@
+import java.io.*;
+import java.util.regex.*;
+
+try
+{
+    File file = new File( basedir, "pom.xml" );
+
+    BufferedReader in = new BufferedReader( new InputStreamReader( new FileInputStream( file ), "UTF-8" ) );
+    StringBuilder buf = new StringBuilder();
+    String line = in.readLine();
+    while ( line != null )
+    {
+        buf.append( line );
+        buf.append( " " );
+        line = in.readLine();
+    }
+
+    Pattern p = Pattern.compile( "\\Q<scm>\\E\\s*\\Q<tag>\\Ev1\\.0\\Q</tag>\\E\\s*\\Q</scm>\\E" );
+    Matcher m = p.matcher( buf.toString() );
+    if ( !m.find() )
+    {
+        System.out.println( "Setting new tag" );
+        return false;
+    }
+}
+catch( Throwable t )
+{
+    t.printStackTrace();
+    return false;
+}
+
+return true;

src/it/it-set-scm-tag-002/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals.1=${project.groupId}:${project.artifactId}:${project.version}:set-scm-tag -DnewTag=v1.0
+invoker.buildResult.1=failure

src/it/it-set-scm-tag-002/pom.xml

@@ -0,0 +1,10 @@
+<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-scm-tag-002</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set-scm-tag</name>
+</project>

src/it/it-set-scm-tag-003/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals.1=${project.groupId}:${project.artifactId}:${project.version}:set-scm-tag
+invoker.buildResult.1=failure

src/it/it-set-scm-tag-003/pom.xml

@@ -0,0 +1,13 @@
+<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-scm-tag-003</artifactId>
+  <version>1.0</version>
+  <packaging>pom</packaging>
+  <name>set-scm-tag</name>
+  <scm>
+    <tag>HEAD</tag>
+  </scm>
+</project>

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

@@ -0,0 +1,80 @@
+package org.codehaus.mojo.versions;
+
+import static org.apache.commons.lang.StringUtils.isBlank;
+
+import java.io.IOException;
+
+import javax.xml.stream.XMLStreamException;
+
+import org.apache.maven.artifact.metadata.ArtifactMetadataRetrievalException;
+import org.apache.maven.model.Model;
+import org.apache.maven.model.Scm;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.codehaus.mojo.versions.api.PomHelper;
+import org.codehaus.mojo.versions.rewriting.ModifiedPomXMLEventReader;
+
+/**
+ * Updates the current project's SCM tag.
+ *
+ * @author Anton Johansson
+ * @since 2.5
+ */
+@Mojo( name = "set-scm-tag", requiresDirectInvocation = true )
+public class SetScmTagMojo
+    extends AbstractVersionsUpdaterMojo
+{
+
+    /**
+     * The new SCM tag to set.
+     *
+     * @since 2.5
+     */
+    @Parameter( property = "newTag" )
+    private String newTag;
+
+    /**
+     * Called when this mojo is executed.
+     *
+     * @throws org.apache.maven.plugin.MojoExecutionException when things go wrong.
+     * @throws org.apache.maven.plugin.MojoFailureException when things go wrong.
+     */
+	@Override
+    public void execute()
+	    throws MojoExecutionException, MojoFailureException
+	{
+	    if ( isBlank(newTag) )
+	    {
+	        throw new MojoFailureException("'newTag' cannot be empty");
+	    }
+
+	    super.execute();
+	}
+
+    @Override
+    protected void update(ModifiedPomXMLEventReader pom) throws MojoExecutionException, MojoFailureException, XMLStreamException, ArtifactMetadataRetrievalException
+    {
+        try
+        {
+            Model model = PomHelper.getRawModel( pom );
+            Scm scm = model.getScm();
+            if (scm == null)
+            {
+                throw new MojoFailureException( "No <scm> was present" );
+            }
+            getLog().info( "Updating from tag " + scm.getTag() + " > " + newTag );
+
+            boolean success = PomHelper.setProjectValue(pom, "/project/scm/tag", newTag );
+            if ( !success )
+            {
+                throw new MojoFailureException( "Could not update the SCM tag" );
+            }
+        }
+        catch ( IOException e )
+        {
+            throw new MojoExecutionException( e.getMessage(), e );
+        }
+    }
+}

src/main/java/org/codehaus/mojo/versions/api/PomHelper.java

@@ -254,12 +254,27 @@ else if ( matchScopeRegex.matcher( path ).matches() )
      */
     public static boolean setProjectVersion( final ModifiedPomXMLEventReader pom, final String value )
         throws XMLStreamException
+    {
+        return setProjectValue( pom, "/project/version", value );
+    }
+
+    /**
+     * Searches the pom re-defining a project value using the given pattern.
+     *
+     * @param pom The pom to modify.
+     * @param pattern The pattern to look for.
+     * @param value The new value of the property.
+     * @return <code>true</code> if a replacement was made.
+     * @throws XMLStreamException if something went wrong.
+     */
+    public static boolean setProjectValue( final ModifiedPomXMLEventReader pom, String pattern, final String value )
+        throws XMLStreamException
     {
         Stack<String> stack = new Stack<String>();
         String path = "";
         final Pattern matchScopeRegex;
         boolean madeReplacement = false;
-        matchScopeRegex = Pattern.compile( "/project/version" );
+        matchScopeRegex = Pattern.compile( pattern );
 
         pom.rewind();