[MPMD-371] Using two ruleset files with same name in different directories

[harbulot]

https://issues.apache.org/jira/browse/MPMD-371

Problem

In version 3.20.0 (without this patch), two PMD rulesets that have the same filename will overwrite each other when staged into the ${project.build.directory}/pmd/rulesets/ directory.

In the following example, the two distinct pmd-ruleset.xml files will both be copied as ${project.build.directory}/pmd/rulesets/pmd-ruleset.xml, so the last copied will overwrite the first: only one of those files will be taken into account.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-pmd-plugin</artifactId>
    <version>${pmd-maven-plugin.version}</version>
    <configuration>
        <rulesets>
            <ruleset>${project.basedir}/pmd-ruleset.xml</ruleset>
            <ruleset>${project-root.basedir}/pmd-ruleset.xml</ruleset>
        </rulesets>
    </configuration>
</plugin>

Proposed solution

This patch prefixes the target filename with a counter, based on the position in the ruleset element.

For example:

<rulesets>
    <ruleset>${project.basedir}/pmd-ruleset.xml</ruleset>
    <ruleset>${project.basedir}/otherfolder/other-pmd-ruleset.xml</ruleset>
    <ruleset>${project.basedir}/otherfolder/pmd-ruleset.xml</ruleset>
</rulesets>

This would create 3 files in ${project.build.directory}/pmd/rulesets/:

• 001-pmd-ruleset.xml (copy of ${project.basedir}/pmd-ruleset.xml)
• 002-other-pmd-ruleset.xml (copy of ${project.basedir}/otherfolder/other-pmd-ruleset.xml)
• 003-pmd-ruleset.xml (copy of ${project.basedir}/otherfolder/pmd-ruleset.xml, now not overwriting the first one)

This only required changes a few lines in PmdReport#getLocationTemp(...) and PmdReport.resolveRulesets(...).

The rest of the changes is just about adapting the expected locations in those tests . (The expected filename is dependent on the order specified in the POM's <rulesets /> element.)

The number format is %03d, so we assume we'll have fewer than 1000 ruleset files. (This may help if ruleset ordering ever mattered. An alternative would be to remove zero-padding.)

---

Following this checklist to help us incorporate your
contribution quickly and easily:

• Make sure there is a JIRA issue filed
  for the change (usually before you start working on it). Trivial changes like typos do not
  require a JIRA issue. Your pull request should address just this issue, without
  pulling in other changes.
• Each commit in the pull request should have a meaningful subject line and body.
• Format the pull request title like [MPMD-XXX] - Subject of the JIRA Ticket,
  where you replace MPMD-XXX with the appropriate JIRA issue. Best practice
  is to use the JIRA issue title in the pull request title and in the first line of the
  commit message.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Run mvn clean verify to make sure basic checks pass. A more thorough check will
  be performed on your pull request automatically.
• You have run the integration tests successfully (mvn -Prun-its clean verify).

If your pull request is about ~20 lines of code you don't need to sign an
Individual Contributor License Agreement if you are unsure
please ask on the developers list.

To make clear that you license your contribution under
the Apache License Version 2.0, January 2004
you have to acknowledge this by using the following check-box.

• I hereby declare this contribution to be licenced under the Apache License Version 2.0, January 2004

[adangel]

Thanks! LGTM