Custom PMD ruleset not working

Question

I have created a customized PMD ruleset xml file to exclude some rule check.

<?xml version="1.0" encoding="UTF-8"?>
<ruleset xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         name="full-pmd-ruleset"
         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">
   <description>Full 5.1.1 PMD rule set</description>
   <rule ref="rulesets/java/coupling.xml">
     <exclude name="LawOfDemeter"/>
   </rule>
   <rule ref="rulesets/java/design.xml">
     <exclude name="GodClass"/>
   </rule>
   <rule ref="rulesets/java/unnecessary.xml">
     <exclude name="UnnecessaryFinalModifier"/>
     <exclude name="UnnecessaryReturn"/>
   </rule>

   <rule ref="rulesets/java/android.xml"/>
   <rule ref="rulesets/java/basic.xml"/>
   <rule ref="rulesets/java/braces.xml"/>
   <rule ref="rulesets/java/clone.xml"/>
   <rule ref="rulesets/java/codesize.xml"/>
   <rule ref="rulesets/java/comments.xml"/>
   <rule ref="rulesets/java/controversial.xml"/>
   <rule ref="rulesets/java/coupling.xml"/>
   <rule ref="rulesets/java/design.xml"/>
   <rule ref="rulesets/java/empty.xml"/>
   <rule ref="rulesets/java/finalizers.xml"/>
   <rule ref="rulesets/java/imports.xml"/>
   <rule ref="rulesets/java/j2ee.xml"/>
   <rule ref="rulesets/java/junit.xml"/>
   <rule ref="rulesets/java/logging-jakarta-commons.xml"/>
   <rule ref="rulesets/java/logging-java.xml"/>
   <rule ref="rulesets/java/javabeans.xml"/>
   <rule ref="rulesets/java/migrating.xml"/>
   <rule ref="rulesets/java/naming.xml"/>
   <rule ref="rulesets/java/optimizations.xml"/>
   <rule ref="rulesets/java/sunsecure.xml"/>
   <rule ref="rulesets/java/strictexception.xml"/>
   <rule ref="rulesets/java/strings.xml"/>
   <rule ref="rulesets/java/unnecessary.xml"/>
   <rule ref="rulesets/java/basic.xml"/>
   <rule ref="rulesets/java/unusedcode.xml"/>

   <rule ref="rulesets/plsql/codesize.xml"/>
   <rule ref="rulesets/plsql/TomKytesDespair.xml"/>
   <rule ref="rulesets/plsql/dates.xml"/>

</ruleset>

And I am using the following command to run PMD with this ruleset:

pmd -d C:\Users\leo\Documents\workspace\SampleProject\src\Sample.java -f html -R CustomRuleset.xml>Report.html

It works well but exclusion of the rules that are mentioned in the xml are not working. It is taking those excluded rules as well.

What am I doing wrong here?

Answer 1

All looks well, except that you are importing some rulesets twice :)

E.g. rulesets/java/coupling.xml is imported once:

<rule ref="rulesets/java/coupling.xml">
    <exclude name="LawOfDemeter"/>
</rule>

And later again, without the excludes:

<rule ref="rulesets/java/coupling.xml"/>

If you remove the duplicated rulesets rulesets/java/coupling.xml, rulesets/java/design.xml, and rulesets/java/unnecessary.xml it will fix the problem.

PMD is just reading your custom ruleset from top to down and stupidly executing, what's in the file: Import all rules from coupling.xml except for LawOfDemeter and later on import again all rules from coupling.xml, this time including LawOfDemeter.

Interestingly, PMD does not have a problem if the rules are imported twice. This case is silently ignored. But maybe PMD should raise an error instead? WDYT?