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[CRASH] When @Getter(lazy = true) has Lambda in the initialization expression. #2300

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NekoCaffeine opened this issue Nov 30, 2019 · 5 comments · Fixed by #2516
Closed

[CRASH] When @Getter(lazy = true) has Lambda in the initialization expression. #2300

NekoCaffeine opened this issue Nov 30, 2019 · 5 comments · Fixed by #2516

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@NekoCaffeine
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NekoCaffeine commented Nov 30, 2019 •
edited

When Javac tried to parse (attr) the JCLambda node in the LazyGetter Method Body generated by @Getter(lazy = true), it crashed because the cache type at that location did not match what was expected.

And in addition to crashing it can cause type inference to fail.

JDK: OpenJDK 13.0.1+9
Lombok: 1.18.11 (2019-09-26 08:56:18 UTC)

Reproduced by the following code:

import lombok.Getter;

public class TestLombokBugLazyGetter {
    
    public static String bar() { return ""; }
    
    @Getter(lazy = true)
    private final Object field = foo(bar(), null, () -> { });
    
    public static Object foo(final Object arg0, final Object arg1, final Runnable arg3) { return null; }
    
}
 An exception has occurred in the compiler (13.0.1). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the
 Java compiler in your report. Thank you.
  java.lang.ClassCastException: class com.sun.tools.javac.tree.JCTree$JCLambda cannot be cast to class com.sun.tools.javac.tree.JCTree$JCMethodInvocation (com.sun.tools.javac.tree.JCTree$JCLambda and com.sun.tools.javac.tree.JCTree$JCMethodInvocation are in module jdk.compiler of loader 'app')
   at jdk.compiler/com.sun.tools.javac.comp.ArgumentAttr$ResolvedMethodType.dup(ArgumentAttr.java:673)
   at jdk.compiler/com.sun.tools.javac.comp.ArgumentAttr.processArg(ArgumentAttr.java:242)
   at jdk.compiler/com.sun.tools.javac.comp.ArgumentAttr.visitLambda(ArgumentAttr.java:301)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCLambda.accept(JCTree.java:1914)
   at jdk.compiler/com.sun.tools.javac.comp.ArgumentAttr.attribArg(ArgumentAttr.java:199)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:664)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribArgs(Attr.java:766)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitApply(Attr.java:2141)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1737)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:710)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitVarDef(Attr.java:1191)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:966)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStats(Attr.java:758)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1311)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1030)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitIf(Attr.java:1856)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCIf.accept(JCTree.java:1492)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStats(Attr.java:758)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1311)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1030)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitSynchronized(Attr.java:1575)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCSynchronized.accept(JCTree.java:1348)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStats(Attr.java:758)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1311)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1030)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitIf(Attr.java:1856)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCIf.accept(JCTree.java:1492)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStats(Attr.java:758)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1311)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1030)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1115)
   at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:876)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:666)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:739)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4843)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4734)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4663)
   at jdk.compiler/com.sun.tools.javac.comp.Attr.attrib(Attr.java:4608)
   at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1346)
   at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:972)
   at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:318)
   at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:176)
   at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:57)
   at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:43)

Cause of error:

https://github.com/rzwitserloot/lombok/blob/a81df33c10f69d49425bdd0606052178a172a66f/src/core/lombok/javac/handlers/HandleGetter.java#L254-L255
This should not be done here.

com/sun/tools/javac/comp/ArgumentAttr.java

    /**
     * Process a method argument; this method allows the caller to specify a custom speculative attribution
     * logic (this is used e.g. for lambdas).
     */
    @SuppressWarnings("unchecked")
    <T extends JCExpression, Z extends ArgumentType<T>> void processArg(T that, Supplier<Z> argumentTypeFactory) {
        UniquePos pos = new UniquePos(that);
        // in UniquePos <init>
        // this.pos = that.pos;
        Z cached = (Z)argumentTypeCache.get(pos);
        // got com.sun.tools.javac.comp.ArgumentAttr.ResolvedMethodType extends ResolvedMemberType<JCMethodInvocation>
        // <T extends JCExpression> T => JCMethodInvocation
        // but in arg (T that) : T => JCLambda
        if (cached != null) {
            //dup existing speculative type
            setResult(that, cached.dup(that, env));
            // ArgumentType<JCMethodInvocation> dup(JCMethodInvocation tree, Env<AttrContext> env)
            // (JCMethodInvocation) tree => java.lang.ClassCastException
            // class JCTree$JCLambda cannot be cast to class JCTree$JCMethodInvocation
        } else {
            Z res = argumentTypeFactory.get();
            argumentTypeCache.put(pos, res);
            setResult(that, res);
        }
    }

Maybe we should discuss this issue or I send a PR to fix it.
@NekoCaffeine NekoCaffeine mentioned this issue Dec 22, 2019
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@rzwitserloot
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If you have a PR, by all means. Including lambdas in that location is fairly exotic, I don't think this is a high priority fix.

@rspilker
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Suggested workaround, also works in some other similar scenario's: move the initializer code to a private static method:

import lombok.Getter;

public class TestLombokBugLazyGetter {
    
    public static String bar() { return ""; }
    
    @Getter(lazy = true)
    private final Object field = fooInitializer();
    
    private static Object fooInitializer() {
        return foo(bar(), null, () -> { });
    }
    
    public static Object foo(final Object arg0, final Object arg1, final Runnable arg3) { return null; }

}

@NekoCaffeine
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This is easy to fix, just let the recursiveSetGeneratedBy method not process the initialization expression.

@NekoCaffeine
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And only when the initialization expression keeps the original position mark, the relevant behavior of Javac is correct.

@rspilker
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Oh, good one!

Rawi01 added a commit to Rawi01/lombok that referenced this issue Jul 12, 2020
@Rawi01
[fixes projectlombok#2300] Keep method argument positions for lazy ge…
03c926a 
…tter initializer
@Rawi01 Rawi01 mentioned this issue Jul 12, 2020
Merged
rspilker pushed a commit that referenced this issue Jul 23, 2020
@Rawi01 @rspilker
[fixes #2300] Keep method argument positions for lazy getter initializer
b1f6372
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Keep method argument positions for lazy getter initializer Rawi01/lombok
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@rzwitserloot @rspilker @NekoCaffeine