Merge pull request #9 from cecom/fix-merge-unrelated-histories

Fix merge unrelated histories

pom.xml

@@ -2,7 +2,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>de.oppermann.pomutils</groupId>
     <artifactId>pomutils</artifactId>
-    <version>1.4</version>
+    <version>develop</version>
 
     <licenses>
         <license>

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

@@ -73,6 +73,18 @@ public POM(String pomFileAsString) throws IOException, XMLStreamException {
 			throw new IllegalArgumentException("File [" + pomFile.getAbsolutePath() + "] not found.");
 		}
 
+		if (pomFile.length() == 0L) {
+			/*
+			 * If we use git merge --allow-unrelated-histories, the base pom file
+			 * can be empty, so it cannot be parsed
+			 */
+			rawModel = null;
+			projectIdentifier = null;
+			projectVersion = "";
+			parentVersion = "";
+			return;
+		}
+
 		initialize();
 	}
 

src/test/java/de/oppermann/pomutils/PomMergeDriverTest.java

@@ -209,4 +209,28 @@ public void testAutoMergeFailed() throws Exception {
 
 		assertEquals("same version now", ourProjectVersion, theirPom.getProjectVersion());
 	}
+
+	public void testAutoMergeWithNoBaseCommit() throws Exception {
+		String myTestSubFolder = "merge/autoMergeSucceded_noConflict_their";
+
+		TestUtils.prepareTestFolder(myTestSubFolder);
+
+		String basePomFile = TestUtils.resourceBaseTestFolder + "/" + myTestSubFolder + "/base.pom.xml";
+		String ourPomFile = TestUtils.resourceBaseTestFolder + "/" + myTestSubFolder + "/our.pom.xml";
+		String theirPomFile = TestUtils.resourceBaseTestFolder + "/" + myTestSubFolder + "/their.pom.xml";
+
+		Ruleset ruleset = new Ruleset(SelectionStrategy.THEIR);
+
+		PomMergeDriver pomMergeDriver = new PomMergeDriver(ruleset, basePomFile, ourPomFile, theirPomFile);
+		int mergeReturnValue = pomMergeDriver.merge();
+
+		assertTrue("merge succeeded", mergeReturnValue == 0);
+
+		POM theirPom = new POM(theirPomFile);
+		POM ourPom = new POM(ourPomFile);
+
+		assertEquals("their", ourPom.getProjectVersion());
+		assertEquals("their", theirPom.getProjectVersion());
+	}
+
 }

src/test/resources/merge/autoMergeWithNoBaseCommit/our.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>de.oppermann.git.pommergedriver</groupId>
+  <artifactId>pommergedriver</artifactId>
+  <version>our</version>
+  <dependencies>
+  	<dependency>
+  		<groupId>org.codehaus.mojo</groupId>
+  		<artifactId>versions-maven-plugin</artifactId>
+  		<version>2.5</version>
+  		<type>maven-plugin</type>
+  	</dependency>
+  </dependencies>
+</project>

src/test/resources/merge/autoMergeWithNoBaseCommit/their.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>de.oppermann.git.pommergedriver</groupId>
+  <artifactId>pommergedriver</artifactId>
+  <version>their</version>
+  <dependencies>
+  	<dependency>
+  		<groupId>org.codehaus.mojo</groupId>
+  		<artifactId>versions-maven-plugin</artifactId>
+  		<version>2.5</version>
+  		<type>maven-plugin</type>
+  	</dependency>
+  </dependencies>
+</project>