[java] StackOverflowError with recursively bound type variable

[slovdahl]

Affects PMD Version: 7.0.0, 7.1.0, 7.2.0, 7.3.0

Description:

I'm trying to upgrade PMD from 6.55.0 to 7.x but the PMD runs just end up in java.lang.StackoverflowErrrors.

ruleset.xml

<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="PMD ruleset"
         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">

  <description>PMD ruleset</description>

  <rule ref="category/java/bestpractices.xml/MissingOverride"/>
  <rule ref="category/java/bestpractices.xml/PrimitiveWrapperInstantiation"/>
  <rule ref="category/java/bestpractices.xml/ReplaceVectorWithList"/>
  <rule ref="category/java/bestpractices.xml/UseStandardCharsets"/>
  <rule ref="category/java/codestyle.xml/ExtendsObject"/>
  <rule ref="category/java/codestyle.xml/PackageCase"/>
  <rule ref="category/java/codestyle.xml/UnnecessaryCast"/>
  <rule ref="category/java/codestyle.xml/UnnecessarySemicolon"/>
</ruleset>

But also fails with just one of the rules in place.

Gradle configuration:

apply plugin: 'pmd'

pmd {
    toolVersion = '7.3.0'
    consoleOutput = true
    incrementalAnalysis = true
    ruleSets = [ "$rootProject.projectDir/gradle/pmd/ruleset.xml" ]
}

gradle.properties:

org.gradle.parallel=true
org.gradle.jvmargs=-Xmx3g

Tested with both Temurin 17 and 21 (the project requires at least 17) on Ubuntu 22.04.

Exception Stacktrace:

The topmost part of the stack trace inline, here is the full stack trace.

Caused by: java.lang.StackOverflowError
        at net.sourceforge.pmd.lang.java.types.Substitution.apply(Substitution.java:45)
        at net.sourceforge.pmd.lang.java.types.Substitution.apply(Substitution.java:28)
        at net.sourceforge.pmd.lang.java.types.SubstVar.subst(SubstVar.java:25)
        at net.sourceforge.pmd.lang.java.types.WildcardTypeImpl.subst(WildcardTypeImpl.java:35)
        at net.sourceforge.pmd.lang.java.types.WildcardTypeImpl.subst(WildcardTypeImpl.java:17)
        at net.sourceforge.pmd.lang.java.types.TypeOps.lambda$subst$0(TypeOps.java:950)
        at net.sourceforge.pmd.lang.java.types.TypeOps.mapPreservingSelf(TypeOps.java:977)
        at net.sourceforge.pmd.lang.java.types.TypeOps.subst(TypeOps.java:950)
        at net.sourceforge.pmd.lang.java.types.JClassType.subst(JClassType.java:78)
        at net.sourceforge.pmd.lang.java.types.JClassType.subst(JClassType.java:54)
        at net.sourceforge.pmd.lang.java.types.TypeOps.subst(TypeOps.java:941)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:213)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:154)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:152)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:662)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:598)
        at net.sourceforge.pmd.lang.java.types.TypeOps.isConvertiblePure(TypeOps.java:415)
        at net.sourceforge.pmd.lang.java.types.TypeOps.mostSpecific(TypeOps.java:1757)
        at net.sourceforge.pmd.lang.java.types.Lub.glb(Lub.java:316)
        at net.sourceforge.pmd.lang.java.types.TypeSystem.glb(TypeSystem.java:723)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:227)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:154)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:152)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:662)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:598)
        at net.sourceforge.pmd.lang.java.types.TypeOps.isConvertiblePure(TypeOps.java:415)
        at net.sourceforge.pmd.lang.java.types.TypeOps.mostSpecific(TypeOps.java:1757)
        at net.sourceforge.pmd.lang.java.types.Lub.glb(Lub.java:316)
        at net.sourceforge.pmd.lang.java.types.TypeSystem.glb(TypeSystem.java:723)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:227)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:154)
        at net.sourceforge.pmd.lang.java.types.TypeConversion.capture(TypeConversion.java:152)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:662)
        at net.sourceforge.pmd.lang.java.types.TypeOps$SubtypeVisitor.isConvertible(TypeOps.java:598)
        at net.sourceforge.pmd.lang.java.types.TypeOps.isConvertiblePure(TypeOps.java:415)
        at net.sourceforge.pmd.lang.java.types.TypeOps.mostSpecific(TypeOps.java:1757)
        at net.sourceforge.pmd.lang.java.types.Lub.glb(Lub.java:316)
        at net.sourceforge.pmd.lang.java.types.TypeSystem.glb(TypeSystem.java:723)

Code Sample demonstrating the issue:

I cannot share the project as is, and I haven't yet been able to figure out what exactly triggers it. Any help in pinpointing the problematic class would be appreciated.

Steps to reproduce:

TBD.

Running PMD through: Gradle 8.8

[oowekyala]

Can you run PMD with the system property pmd.error_recovery set to whatever value? This will log the StackoverflowError as a regular error and show you the name of the file that causes the error. I don't know how to set properties with gradle, but maybe you can download a release and run the CLI directly.

[slovdahl]

Thanks for the tip!

Just for future reference, I get the feeling this is not possible to do using Gradle right now. I tried with both ./gradlew -Dpmd.error_recovery=true :component:pmdMain and ./gradlew -Ppmd.error_recovery=true :component:pmdMain, but I'm not getting it logged as a normal error. I also tried modifying the pmd { .. } block and the pmdMain { .. } block, but AFAICT there is no support for configuring system properties for the forked JVM used for running PMD in this case.

In any case, I downloaded the raw PMD binary package and ran it against the component and immediately got the same StackoverflowError. 👍 And with PMD_JAVA_OPTS="-Dpmd.error_recovery" pmd-bin-7.3.0/bin/pmd check -d component/src/main/java/ -R gradle/pmd/ruleset.xml -f text I also get two files with StackOverflowError: null as the error in the output. Time is up for today, but I'll try to extract a minimal reproducer tomorrow.

[slovdahl]

Here's a minimal reproducer: https://github.com/slovdahl/pmd-stackoverflow-reproducer. PMD fails on just the Settings.java file, but I included the other files to have something that actually compiles and is valid Java.

[DanySK]

This bug is hitting me, too: https://scans.gradle.com/s/c5nsujr23bwik/failure?expanded-stacktrace=WyIwIiwiMC0xIiwiMC0xLTItMyJd#1