Create rule for SCM tag (used by maven-release plugin)

Author: Sébastien Latre

.gitignore

@@ -3,3 +3,4 @@ target
 .classpath
 .project
 dependency-reduced-pom.xml
+/.idea

pom.xml

@@ -95,7 +95,7 @@
         <dependency>
             <groupId>org.codehaus.mojo</groupId>
             <artifactId>versions-maven-plugin</artifactId>
-            <version>2.1</version>
+            <version>2.7</version>
             <type>maven-plugin</type>
             <exclusions>
                 <exclusion>

src/main/java/de/oppermann/pomutils/rules/ScmTagRule.java

@@ -0,0 +1,93 @@
+package de.oppermann.pomutils.rules;
+
+import de.oppermann.pomutils.select.SelectionStrategy;
+import de.oppermann.pomutils.util.POM;
+import de.oppermann.pomutils.util.VersionFieldType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/*
+ * 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.
+ */
+
+/**
+ *
+ * @author Sébastien Latre
+ * 
+ */
+
+public class ScmTagRule extends AbstractRule {
+
+	private final Logger logger = LoggerFactory.getLogger(ScmTagRule.class);
+
+	public ScmTagRule() {
+		// for creating this instance via snakeyaml
+	}
+
+	public ScmTagRule(SelectionStrategy strategy) {
+		super(strategy);
+		logger.debug("Using ScmTagRule with strategy [{}]", strategy.toString());
+	}
+
+	@Override
+	public void evaluate(POM basePom, POM ourPom, POM theirPom) {
+		String baseScmTag = basePom.getScmTag();
+		String ourScmTag = ourPom.getScmTag();
+		String theirScmTag = theirPom.getScmTag();
+		if (baseScmTag != null && ourScmTag != null && theirScmTag != null && !ourScmTag.equals(theirScmTag)) {
+			String newScmTag;
+			if (baseScmTag.equals(ourScmTag)) {
+				/*
+				 * Our ScmTag hasn't changed, so no conflict. Just use theirScmTag.
+				 */
+				newScmTag = theirScmTag;
+			} else if (baseScmTag.equals(theirScmTag)) {
+				/*
+				 * Their scmTag hasn't changed, so no conflict. Just use ourScmTag.
+				 */
+				newScmTag = ourScmTag;
+			} else {
+				/*
+				 * Both our scmTag and their scmTag have changed from the base, so conflict.
+				 */
+				switch (getStrategy()) {
+					case OUR:
+						newScmTag = ourScmTag;
+						break;
+					case THEIR:
+						newScmTag = theirScmTag;
+						break;
+					default:
+						throw new IllegalArgumentException("Strategy [" + getStrategy().toString() + "] not implemented.");
+				}
+			}
+
+			if (newScmTag != null) {
+				/*
+				 * newScmTag can be null if the user wants to skip resolution.
+				 */
+
+				POM pomToAdjust = newScmTag.equals(ourScmTag)
+						? theirPom
+						: ourPom;
+
+				pomToAdjust.setScmTag(newScmTag);
+			}
+		}
+	}
+}

src/main/java/de/oppermann/pomutils/util/POM.java

@@ -65,6 +65,7 @@ public class POM {
 	private String projectVersion;
 	private String parentVersion;
 	private String projectIdentifier;
+	private String scmTag;
 	private Model rawModel;
 
 	public POM(String pomFileAsString) throws IOException, XMLStreamException {
@@ -82,6 +83,7 @@ public POM(String pomFileAsString) throws IOException, XMLStreamException {
 			projectIdentifier = null;
 			projectVersion = "";
 			parentVersion = "";
+			scmTag = "";
 			return;
 		}
 
@@ -104,6 +106,9 @@ private void initialize() throws IOException, XMLStreamException {
 		parentVersion = rawModel.getParent() != null
 		        ? rawModel.getParent().getVersion()
 		        : null;
+		scmTag = rawModel.getScm() != null
+				? rawModel.getScm().getTag()
+				: null;
 	}
 
 	private String calculateProjectIdentifier() {
@@ -161,6 +166,14 @@ public String getProjectIdentifier() {
 		return projectIdentifier;
 	}
 
+	/**
+	 *
+	 * @return the SCM tag or null if the SCM tag is unset
+	 */
+	public String getScmTag() {
+		return scmTag;
+	}
+
 	/**
 	 * Sets the parent version to the given one, if it exists
 	 * @param newVersion
@@ -188,6 +201,20 @@ public void setProjectVersion(String newVersion) {
 
 	}
 
+	/**
+	 * Sets the SCM tag to the given one, if it exists
+	 * @param newScmTag
+	 */
+	public void setScmTag(String newScmTag) {
+		if (this.scmTag == null || this.scmTag.equals(newScmTag)) {
+			return;
+		}
+		logger.debug("Adjusting scm tag from [{}] to [{}] of [{}] for [{}]", this.scmTag, newScmTag, getPath(), this.projectIdentifier);
+		this.scmTag = newScmTag;
+		this.changed = true;
+
+	}
+
 	/**
 	 * Saves the pom, if it was changed.
 	 */
@@ -204,6 +231,10 @@ public void savePom() throws IOException, XMLStreamException {
 			changed |= PomHelper.setProjectParentVersion(pom, this.parentVersion);
 		}
 
+		if (this.scmTag != null) {
+			changed |= PomHelper.setProjectValue(pom, "/project/scm/tag", this.scmTag);
+		}
+
 		if (!changed) {
 			return;
 		}