phpmd.xml
<?xml version="1.0"?>
<ruleset
name="wordpress-muplugin-installer rules"
xmlns="http://pmd.sf.net/ruleset/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd"
>
<rule ref="rulesets/cleancode.xml"/>
<rule ref="rulesets/codesize.xml"/>
<rule ref="rulesets/controversial.xml"/>
<rule ref="rulesets/design.xml"/>
<rule ref="rulesets/unusedcode.xml"/>
<rule ref="rulesets/naming.xml">
<exclude name="ShortVariable"/>
</rule>
<rule ref="rulesets/naming.xml/ShortVariable">
<properties>
<property name="minimum" value="3"/>
<property name="exceptions" value="fs,id,io"/>
</properties>
</rule>
</ruleset>