[MDEP-595] Maven 3.5.2 introduces intermittent test-jar dependency failures in multi-module builds

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Cannot Reproduce
• Component/s: resolve
• Environment: Windows 7 / Server 2012 ; Maven 3.5.2 ; JDK 1.8 ; maven-jar-plugin 2.6 ; maven-dependency-plugin 2.10 & 3.0.2
• Assignee: Unassigned
• Reporter: Beirtí Ó'Nunáin
• Created: 10/Jan/18 10:53
• Updated: 12/Apr/21 10:27
• Resolved: 01/May/20 17:36

Description

This issue never presented in 6 months of running a multi-module build on Maven 3.2.5. It began to present in Maven 3.5.2.

As it's intermittent, will obviously be difficult to reproduce, but here is a knocked-down version of our project:

• parent-aggregator
  • project_a
  • project_b
    • builds jar and test-jar

Project B has following pom snippet:

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-jar-plugin</artifactId>
				<executions>
					<execution>
						<goals>
							<goal>test-jar</goal>
						</goals>
					</execution>
				</executions>
			</plugin>

Project A has a <type>test-jar</type> on Project B. The dependency declaration is as follows

<dependency>
  <groupId>mygroup</groupId>
  <artifactId>projectB</artifactId>
  <version>${project.version}</version>
  <type>test-jar</type>
  <scope>test</scope
</dependency>

Using Maven 3.2.5, the dependency had been declared using <classifier>tests</classifier> and this worked fine. Following a recommendation on this page: https://stackoverflow.com/questions/1725476/maven-test-dependency-in-multi-module-project which refers to the previous editions of the guide suggesting classifier, I switched to '<type>' but still have the same intermittent issue.

This page suggests that using 'test-jar' is supported but not ideal: https://maven.apache.org/plugins/maven-jar-plugin/examples/create-test-jar.html

Should we expect multi-module builds to work with test-jar dependencies or should we be using a separate 'tests' module instead?