[Issue mojohaus#48] Fix rootlocation goal.

src/it/rootlocation-in-submodule/invoker.properties

@@ -0,0 +1,3 @@
+invoker.goals = validate
+invoker.buildResult = success
+invoker.project = submodule

src/it/rootlocation-in-submodule/pom.xml

@@ -0,0 +1,36 @@
+<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>org.codehaus.mojo</groupId>
+	<artifactId>build-helper-rootlocation-parent</artifactId>
+	<version>1-SNAPSHOT</version>
+	<packaging>pom</packaging>
+
+	<name>rootlocation search top root</name>
+	<description>
+    Tests that rootlocation finds the highest basedir.
+  </description>
+
+	<modules>
+		<module>submodule</module>
+	</modules>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>rootlocation</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

src/it/rootlocation-in-submodule/submodule/pom.xml

@@ -0,0 +1,16 @@
+<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>
+
+	<parent>
+		<groupId>org.codehaus.mojo</groupId>
+		<artifactId>build-helper-rootlocation-parent</artifactId>
+		<version>1-SNAPSHOT</version>
+	</parent>
+
+	<artifactId>project</artifactId>
+	<packaging>jar</packaging>
+
+	<name>rootlocation sub project</name>
+
+</project>

src/it/rootlocation-in-submodule/verify.groovy

@@ -0,0 +1,8 @@
+File file = new File( basedir, "build.log" )
+assert file.exists()
+
+String text = file.getText("utf-8")
+
+assert text.matches('(?ms)(.*?)define property rootlocation = "(.*)/rootlocation-in-submodule"(.*?)')
+
+return true

src/it/rootlocation-run-only-at-exec-root/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals = validate
+invoker.buildResult = success

src/it/rootlocation-run-only-at-exec-root/pom.xml

@@ -0,0 +1,39 @@
+<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>org.codehaus.mojo</groupId>
+	<artifactId>build-helper-rootlocation-parent</artifactId>
+	<version>1-SNAPSHOT</version>
+	<packaging>pom</packaging>
+
+	<name>rootlocation run only at execution root</name>
+	<description>
+    Tests that rootlocation is executed only at execution top level.
+  </description>
+
+	<modules>
+		<module>submodule</module>
+	</modules>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>rootlocation</goal>
+						</goals>
+						<configuration>
+							<runOnlyAtExecutionRoot>true</runOnlyAtExecutionRoot>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

src/it/rootlocation-run-only-at-exec-root/submodule/pom.xml

@@ -0,0 +1,16 @@
+<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>
+
+	<parent>
+		<groupId>org.codehaus.mojo</groupId>
+		<artifactId>build-helper-rootlocation-parent</artifactId>
+		<version>1-SNAPSHOT</version>
+	</parent>
+
+	<artifactId>project</artifactId>
+	<packaging>jar</packaging>
+
+	<name>rootlocation sub project</name>
+
+</project>

src/it/rootlocation-run-only-at-exec-root/verify.groovy

@@ -0,0 +1,9 @@
+File file = new File( basedir, "build.log" )
+assert file.exists()
+
+String text = file.getText("utf-8")
+
+assert text.matches('(?ms)(.*?)define property rootlocation = "(.*)/rootlocation-run-only-at-exec-root"(.*?)')
+assert text.contains("Skip getting the rootlocation in this project because it's not the Execution Root")
+
+return true

src/it/rootlocation/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals = validate
+invoker.buildResult = success

src/it/rootlocation/pom.xml

@@ -0,0 +1,32 @@
+<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>org.codehaus.mojo</groupId>
+	<artifactId>build-helper-rootlocation</artifactId>
+	<version>1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>rootlocation</name>
+	<description>
+    Tests that rootlocation is set.
+  </description>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>rootlocation</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

src/it/rootlocation/verify.groovy

@@ -0,0 +1,8 @@
+File file = new File( basedir, "build.log" )
+assert file.exists()
+
+String text = file.getText("utf-8")
+
+assert text.matches('(?ms)(.*?)define property rootlocation = "(.*)/rootlocation"(.*?)')
+
+return true

src/main/java/org/codehaus/mojo/buildhelper/RootLocationMojo.java

@@ -4,6 +4,9 @@
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.MavenProject;
+
+import javax.annotation.Nonnull;
 
 /**
  * This goal will get the location of the root folder within a multi module build as a property {@code rootlocation}.
@@ -42,8 +45,25 @@ public void execute()
         }
         else
         {
-            defineProperty( rootLocationProperty, session.getTopLevelProject().getBasedir().getAbsolutePath() );
+            MavenProject topLevelProject = findHighestParentProject(session.getTopLevelProject());
+            defineProperty( rootLocationProperty, topLevelProject.getBasedir().getAbsolutePath() );
+        }
+    }
+
+    private MavenProject findHighestParentProject(@Nonnull MavenProject project)
+    {
+        // search up model hierarchy to find the highest basedir location
+        MavenProject parent = project;
+        while (parent.getParent() != null)
+        {
+            if (parent.getParent().getBasedir() == null)
+            {
+                // we've hit a parent that was resolved. Stop going higher up in the hierarchy
+                break;
+            }
+            parent = parent.getParent();
         }
+        return parent;
     }
 
 }