[java] AccessorMethodGeneration false positives with compile time constants #808
Description
Affects PMD Version: 5.8.1, 6.0.0 (and probably 5.5.4 upwards since the rule was introduced)
Rule: AccessorMethodGeneration
Description: constants are inlined at compile time, so no method is generated to access them.
Valid violations confirmed via javac Outer.java && javap Outer.class which shows the access$ methods.
Code Sample demonstrating the issue:
@SuppressWarnings("unused")
class Outer {
private static final String CONST_STRING = "value";
private static final String CALCULATED_STRING = "value" + 0;
private static final int LITERAL = 0;
private static final int CALCULATED = LITERAL * 2;
private static final int REFERENCED = Thread.MIN_PRIORITY;
private static final int CAST = (int) 0L;
private static final long NON_CONSTANT = java.util.concurrent.TimeUnit.SECONDS.toMillis(10);
private static final int LATE_INIT;
static {
LATE_INIT = 0;
}
class Inner {
@Override
public String toString() {
return "" // separate lines so the rule violations show up better
+ CONST_STRING
+ CALCULATED_STRING
+ LITERAL
+ CALCULATED
+ LATE_INIT // valid violation
+ REFERENCED
+ CAST
+ NON_CONSTANT // valid violation
;
}
}
}Running PMD through: Gradle (5.8.1) and CLI (6.0.0 pmd -d . -format text -R java-design)
Workaround
I was able to suppress the most basic false positives (CONST_STRING and LITERAL) via:
<rule ref="rulesets/java/design.xml/AccessorMethodGeneration">
<properties>
<!-- Ignore references to `private static final * * = <literal>`
Suppress via XPath: current node (access that generates the accessor) is .
Check if there exists a FieldDeclaration (private static final)
which has a VariableInitializer with a Literal
and the name (@Image) of the declaration is the same as the accessed member.
TODO calculated constant values still show up as false positive
-->
<property name="violationSuppressXPath" value="
.[@Image =
//FieldDeclaration[@Private = 'true' and @Static='true' and @Final='true']
/VariableDeclarator[
VariableInitializer/Expression/PrimaryExpression[not(PrimarySuffix)]/PrimaryPrefix/Literal
]/VariableDeclaratorId/@Image
]" />
</properties>
</rule>