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Verifier crashes on `!` (or another unary operator) applied to a call whose type cannot be resolved

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評估

難度
3/5
預估耗時
1-2 天
新手友好度
65/100
Issue 類型
缺陷
描述清晰度
描述清楚
活躍度
活躍
技術堆疊
java
領域
compilers

研究方向

Start with the stack trace: OperationsChecker.getUnaryOpRefinements (OperationsChecker.java:179) calls Context.addInstanceToContext (Context.java:164), which reaches Context.addInstanceVariable (Context.java:267) with a null type. Run the minimal Repro snippet from the issue, with org.example.missing absent from the classpath, to reproduce the NullPointerException. Done means the snippet verifies with the compilation warning instead of crashing, and the related reproducers for #388 and #390 are still considered.

由索引模型根據 Issue 內容生成。

描述

bug

Impact: verification stops with an internal error: 3 of the 53 real-world files below.

Description

!x.m() where x's class is not on the classpath: OperationsChecker.getUnaryOpRefinements adds the operand to the context, and Context.addInstanceVariable calls getSuperclass() on its type, which is null.

Minimal reproducer (org.example.missing is not on the classpath)

import org.example.missing.Settings;

public class Repro {
    static void start(Settings settings) {
        if (!settings.enabled()) {
            return;
        }
    }
}

Expected

Correct! Passed Verification. (with the "Java compilation encountered issues" warning).

Actual

Exception in thread "main" java.lang.RuntimeException: 
Error while checking CtMethodImpl
  on start(Settings settings) { 
  at Repro.java:4
  with 
Error while checking CtBlockImpl
  on { 
  at Repro.java:4
  with 
Error while checking CtIfImpl
  on if (!settings.enabled()) { 
  at Repro.java:5
  with Cannot invoke "spoon.reflect.reference.CtTypeReference.getSuperclass()" because "type" is null
	at liquidjava.processor.refinement_checker.TypeChecker.scan(TypeChecker.java:80)
	at spoon.reflect.visitor.CtScanner.scan(CtScanner.java:189)
	at spoon.reflect.visitor.CtScanner.scan(CtScanner.java:154)
	at spoon.reflect.visitor.CtScanner.visitCtClass(CtScanner.java:363)
	at liquidjava.processor.refinement_checker.RefinementTypeChecker.visitCtClass(RefinementTypeChecker.java:97)
	at spoon.support.reflect.declaration.CtClassImpl.accept(CtClassImpl.java:63)
	at liquidjava.processor.RefinementProcessor.lambda$processPackage$3(RefinementProcessor.java:51)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at liquidjava.processor.RefinementProcessor.processPackage(RefinementProcessor.java:50)
	at liquidjava.processor.RefinementProcessor.process(RefinementProcessor.java:35)
	at liquidjava.processor.RefinementProcessor.process(RefinementProcessor.java:15)
	at spoon.support.visitor.ProcessingVisitor.scan(ProcessingVisitor.java:72)
	at spoon.support.QueueProcessingManager.process(QueueProcessingManager.java:118)
	at spoon.support.QueueProcessingManager.process(QueueProcessingManager.java:132)
	at liquidjava.api.CommandLineLauncher.launch(CommandLineLauncher.java:92)
	at liquidjava.api.CommandLineLauncher.main(CommandLineLauncher.java:41)
...
Caused by: java.lang.NullPointerException: Cannot invoke "spoon.reflect.reference.CtTypeReference.getSuperclass()" because "type" is null
	at liquidjava.processor.context.Context.addInstanceVariable(Context.java:267)
	at liquidjava.processor.context.Context.addInstanceToContext(Context.java:164)
	at liquidjava.processor.refinement_checker.general_checkers.OperationsChecker.getUnaryOpRefinements(OperationsChecker.java:179)

Reproduced on main at dcfc4eb2 (liquidjava-verifier 0.0.35).

Real-world files that hit it

  • if (!appProperties.simulator().enabled()) { — skyleedevzero86/carebridge-platform (file)
  • if (!Game.isInNoGUIMode()) { — gurkenlabs/litiengine (file)
  • (!context.isExportedEquipment(identifiable) || extensions.isEmpty()) { — stvzhou/powsybl-core (file)

Context

Found while running LiquidJava on the original repository files of 53 real-world typestate and refinement bugs (the same files as our study exercises, before simplification). Each file is verified on its own, as a user would on one file of a project, so the project's other classes and its dependencies are not on the classpath. On main this crash and the two related ones (#388 binary operator, #389 unary operator, #390 field read) stop verification in 33 of the 53 files.

主要語言
Java
星號
67
分支
36
平均合併
2 天 3 小時
30 天內合併 PR
29

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