How to break a maven build when there is a dependency conflict?

Question

I ran mvn dependency:tree for a project and I saw output like the following:

[INFO] my:project:jar:1.0.0-SNAPSHOT
[INFO] +- some.other:library:jar:2.0.0:comp         


        

Answer 1

The maven-enforcer-plugin has a dependencyConvergence configuration which does what I want. Coincidentally, the example from the documentation uses slf4j.

Configure it like this:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-enforcer-plugin</artifactId>
    <version>1.0</version>
    <executions>
        <execution>
            <id>enforce</id>
            <configuration>
                <rules> 
                    <DependencyConvergence />
                </rules>
            </configuration>
            <goals> 
                <goal>enforce</goal>
            </goals>
        </execution>
    </executions>
</plugin>

This combination of dependencies will cause a build to fail:

  <dependencies>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-jdk14</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-nop</artifactId>
      <version>1.6.0</version>
    </dependency>
  </dependencies>  

With this being logged during compilation:

[ERROR]
Dependency convergence error for org.slf4j:slf4j-api:1.6.1 paths to dependency are:
+-org.myorg:my-project:1.0.0-SNAPSHOT
  +-org.slf4j:slf4j-jdk14:1.6.1
    +-org.slf4j:slf4j-api:1.6.1
and
+-org.myorg:my-project:1.0.0-SNAPSHOT
  +-org.slf4j:slf4j-nop:1.6.0
    +-org.slf4j:slf4j-api:1.6.0

Answer 2

Though dated, I think this SO discussion is related.