[java] XPath "//MethodCall/AmbiguousName" not match

[koalalam]

Affects PMD Version: 7.0.0

Rule: Custom XPath Rule to capture the use of old version of Apache Commons Collections

XPath 3.1

//ImportDeclaration[starts-with(@ImportedName,'org.apache.commons.collections.')]
| //MethodCall/AmbiguousName[starts-with(@Image,'org.apache.commons.collections.')]

Description:

The XPath expression works in Designer, but not in PMD.

Code Sample demonstrating the issue:

import org.apache.commons.collections.CollectionUtils;

public class Test {
  public void Test() {
    Collection<String> emptyCollection = new ArrayList<>();
    boolean good4 = org.apache.commons.collections.CollectionUtils.isEmpty(emptyCollection);  // Line 6
  }
}

Expected outcome:

PMD should report a violation at line 6 but doesn't. This is a false-negative.

Running PMD through: Gradle

[oowekyala]

You should probably write

//MethodCall/TypeExpression[pmd-java:typeIs('org.apache.commons.collections.CollectionUtils')]

This should also work in eg just CollectionUtils.isEmpty(...) without qualification. AmbiguousName nodes are rewritten to TypeExpression if your analysis classpath is complete (ie includes this apache library). This is probably what happens to make your expression with AmbiguousName not match.

[jsotuyod]

You can set the auxclasspath on the designer to test this out from the View -> Analysis Classpath menu.

[koalalam]

You should probably write

//MethodCall/TypeExpression[pmd-java:typeIs('org.apache.commons.collections.CollectionUtils')]

How about a prefix match against a package name?

Below works in PMD v6.x:

//ImportDeclaration[starts-with(@ImportedName,'org.apache.commons.collections.')]
| //PrimaryPrefix/Name[starts-with(@Image, 'org.apache.commons.collections.')]

Is there a way to do it in PMD v7? Thank you very much!

[oowekyala]

Currently you can do that in XPath for the import but not for the method call. You can do it with a java rule though. methodCall.getOverloadSelectionInfo().getMethodType().getSymbol().getPackageName()

[koalalam]

Thanks @oowekyala. Any chance that we can have function e.g. pmd-java:packageStartsWith that we can use to build xpath rule?

[oowekyala]

I don't think a function would be useful here. We can easily add an attribute @PackageQualifier to ASTClassType though.

[koalalam]

@oowekyala Great! I assume we can then use starts-with(@PackageQualifier, 'org.apache.commons.collections.') like we did in PMD v6.

Please advise if raising a new issue for this feature request is needed. Thanks again!

[jsotuyod]

Yes, I'd recommend creating a new separate issue for that. Keeping track of all issues, when the details go into long threads is really difficult.