Last week I wrote about the ImmobilienScout24/illegal-transitive-dependency-check rule for Maven Enforcer Plug-in. There are two other Maven Plug-ins that can be useful.
The mbknor/deptools is another rule for the Maven Enforcer Plug-in. It will scan your project dependency tree, looking for transitive dependencies. Whenever it finds a transitive dependency, it will keep track of the versions. And if, because of the way your dependencies and transitive dependencies are organised, you end up with a version that is not the newest, the build will fail.
So, for example, if you have
commons-lang3 as transitive dependency of two other dependencies, but one is using 3.4 and the other 3.5. If for any reason you are using 3.4 instead of 3.5, you will have a build error.
Here’s an example of the plug-in configuration.
<project> ... <build> <plugins> <plugin> <groupId>deptools.plugin</groupId> <artifactId>maven-deptools-plugin</artifactId> <version>1.3</version> <executions> <execution> <phase>compile</phase> <goals> <goal>version-checker</goal> </goals> </execution> </executions> </plugin> </plugins> </build> <pluginRepositories> <pluginRepository> <id>mbk_mvn_repo</id> <name>mbk_mvn_repo</name> <url>https://raw.githubusercontent.com/mbknor/mbknor.github.com/master/m2repo/releases</url> </pluginRepository> </pluginRepositories> ... </project>
mvn clean verify will execute the Maven Enforcer Plug-in
enforce goal, which will call the deptools check. As you may have noticed, you also need to download the plug-in from GitHub, as it is not released to Maven Central.
I do not use it for this reason, and also because I normally spend some time looking at the dependency tree anyway, but every now and then when I work on a new project I like quickly running it just to see what are the dependencies that are being shadowed by older versions.
<project> ... <build> <plugins> <plugin> <groupId>net.revelc.code</groupId> <artifactId>impsort-maven-plugin</artifactId> <version>1.0.0</version> <configuration> <groups>java.,javax.,org.,com.</groups> <staticGroups>java,*</staticGroups> <excludes> <exclude>**/thrift/*.java</exclude> </excludes> </configuration> <executions> <execution> <id>sort-imports</id> <goals> <goal>sort</goal><!-- runs at process-sources phase by default --> </goals> </execution> </executions> </plugin> </plugins> </build> ... </project>
I am neutral on imports order, though in cases where you have several contributors submitting pull requests, it can probably be useful to reduce the number of interactions. In other words, if a user submits a pull request and you have an automated check, then the user would be automatically notified about changes that s/he needs to do in order for his pull request to be accepted.
I am not using any of these two plug-ins, but wanted to save it somewhere in case I needed to use them in the future, and also to share with others. Besides most common plug-ins (PMD, CheckStyle, FindBugs), I normally use at least some Maven Enforcer Plug-in rules, and the OWASP plug-in.
While most of the time we spend writing code, preparing the infrastructure, and deploying and testing, I got bitten by some maven build bugs a few times, and had to spend days/weeks debugging some of these. So hope some of these posts save some hours of someone out there in a similar situation.
♥ Open Source