Custom ruleset

[alivanni]

Hi,

I am going trough the process of creating custom ruleset described here: https://docs.pmd-code.org/pmd-doc-6.55.0/pmd_userdocs_making_rulesets.html
What is not clear to me - does custom ruleset initially completely empty in terms of functionality, or it kind of implicitly inherits all the default rules and behaviour? Other words, if I customise one existing rule in my ruleset - this rule is the only thing that going to be checked or default behaviour of all other rules will also be executed?

Thanks,
Aleksandr

[jsotuyod]

There are no default rules in PMD (some tools such as Gradle may set defaults on their own, but that's not curated by us).

Having said that, you can provide multiple ruleset files to PMD, so you can provide whatever defaults you have + your custom ruleset customizing that one rule; just be mindful that the order matters (if I recall correctly, first one wins).

So, if you set 2 ruleset files ruleSet1.xml and ruleSet2.xml in that order, and both configure rule A in a different way, the version from ruleSet1.xml is the one used.

This is however undocumented behavior, I don't think we even print a warning for this…

[alivanni]

I see. And is it possible instead of maintaining two rulesets somehow inherit all java rules for instance in my xml and then apply customisation on top of that? What complicates the thing is that I am using PMD in a context of Codacy code check. Probably "default" set is somehow defined inside Codacy itself. But now I am quite confuse how can I customise singe Java rule without disabling all other rules.

[jsotuyod]

Yes you can! you can have your ruleset import a complete category and exclude / configure any rules within that.

For instance this one here does exactly that, importing all existing categories (except security) and manually excluding / overriding particular rules. https://github.com/Monits/static-code-analysis-plugin/blob/staging/defaults/pmd/pmd-6.xml

[adangel]

This is actually documented here: https://docs.pmd-code.org/latest/pmd_userdocs_making_rulesets.html#bulk-adding-rules under "Bulk-adding rules"

[akansha1808]

Hye! actually I also tried to create my own custom ruleset but don't know exactly how to override the message for a particular rule in my ruleset. I tried to do in the way it is documented but it still showed the original message. For eg. I tried to modify the message of UseUtilityClass in quickstart.xml ruleset but it didnot change. Can anyone please suggest me a way how i can modify the message of a particular rule.

[jsotuyod]

That is actually an implementation issue. The rule implementation hardcodes a message instead of using the on defined in the XML. There are legit uses of this (ie: rules that provide multiple messages with greater detail for particular situations), but this one only produces the one message…

pmd/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/design/UseUtilityClassRule.java

Lines 81 to 82 in ae76c8f

	message = "This utility class has a non-private constructor";
	asCtx(data).addViolationWithMessage(klass, message);

I created #5023 to track this issue.

[akansha1808]

Thankyou so much!!