groovy

NullPointerException in compiler when using @Immutable

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Minor Minor
  • Resolution: Fixed
  • Affects Version/s: 1.8.6
  • Fix Version/s: 2.1.4
  • Component/s: Compiler
  • Labels:
    None
  • Environment:
    Mac OS/X Lion, Java 1.6.0_29
  • Testcase included:
    yes
  • Number of attachments :
    2

Description

When using @Immutable with a certain combination of properties, I get a NullPointerException as shown in the stack trace below.

The most basic way I've found to reproduce this is with the two classes. Note that if I remove the 'final' keyword from properties, or don't include an implementation of toString() in the TestBean class, then the error goes away.

java.lang.NullPointerException
at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:35)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:179)
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
at org.codehaus.groovy.ast.ClassCodeExpressionTransformer.visitIfElse(ClassCodeExpressionTransformer.java:80)
at org.codehaus.groovy.ast.stmt.IfStatement.visit(IfStatement.java:41)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:102)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:113)
at org.codehaus.groovy.ast.ClassCodeExpressionTransformer.visitConstructorOrMethod(ClassCodeExpressionTransformer.java:50)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructor(ClassCodeVisitorSupport.java:120)
at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1166)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:51)
at org.codehaus.groovy.control.OptimizerVisitor.visitClass(OptimizerVisitor.java:49)
at org.codehaus.groovy.control.CompilationUnit$6.call(CompilationUnit.java:778)
at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1122)
at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:594)
at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:572)
at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:549)
at org.codehaus.jdt.groovy.internal.compiler.ast.GroovyCompilationUnitDeclaration.processToPhase(GroovyCompilationUnitDeclaration.java:171)
at org.codehaus.jdt.groovy.internal.compiler.ast.GroovyCompilationUnitDeclaration.generateCode(GroovyCompilationUnitDeclaration.java:1526)
at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:831)
at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:137)
at java.lang.Thread.run(Thread.java:680)

  1. File
    OtherBean.groovy
    14/May/12 2:41 PM
    0.2 kB
    Jan Stette
  2. File
    TestBean.groovy
    14/May/12 2:41 PM
    0.2 kB
    Jan Stette

Activity

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Paul King added a comment -

Can you provide a few more details on how you are invoking the compiler?

Running the following script in groovyConsole seemed fine:

package bug

import groovy.transform.Immutable

@Immutable class TestBean {
    final String value
    final OtherBean other
    String toString() { "Something" }
}

@Immutable class OtherBean {
    enum Type { One, Two, Three }
    final Integer value
    final Type type
}

println new TestBean('foo', new OtherBean(30, OtherBean.Type.One))
// => Something

Also, running:

> groovyc bug/TestBean.groovy

Seemed to work fine using your two source files.

So far I have just tried Groovy 1.8.6 and Java 1.6.0_31 (32-bit) on Windows.

Show
Paul King added a comment - Can you provide a few more details on how you are invoking the compiler? Running the following script in groovyConsole seemed fine: package bug import groovy.transform.Immutable @Immutable class TestBean { final String value final OtherBean other String toString() { "Something" } } @Immutable class OtherBean { enum Type { One, Two, Three } final Integer value final Type type } println new TestBean('foo', new OtherBean(30, OtherBean.Type.One)) // => Something Also, running: > groovyc bug/TestBean.groovy Seemed to work fine using your two source files. So far I have just tried Groovy 1.8.6 and Java 1.6.0_31 (32-bit) on Windows.
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Jan Stette added a comment -

I was compiling this in Eclipse (3.7,1), using the Groovy plugin (2.6.1.xx-20120301-1000-e37-RELEASE).

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Jan Stette added a comment - I was compiling this in Eclipse (3.7,1), using the Groovy plugin (2.6.1.xx-20120301-1000-e37-RELEASE).
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Paul King added a comment -

Any chance you can also try on the command line or groovyConsole? That would help us narrow down our search. Thanks.

Show
Paul King added a comment - Any chance you can also try on the command line or groovyConsole? That would help us narrow down our search. Thanks.
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Jan Stette added a comment -

I've tried both the command line and groovyConsole as well and they work fine. But I can still reproduce this consistently when compiling in Eclipse. I realise now that it's behaving strangely - when I get the error, I can change something insignificant, i.e. the string returned trom TestBean.toString(), and then the error goes away. When I try to do another insignificant change and build again, the error happens again.

Does this mean it's actually a bug in the groovy plugin's interaction with the compiler?

FWIW I have no such problems after changing my classes to use @Canonical instead of @Immutable.

Show
Jan Stette added a comment - I've tried both the command line and groovyConsole as well and they work fine. But I can still reproduce this consistently when compiling in Eclipse. I realise now that it's behaving strangely - when I get the error, I can change something insignificant, i.e. the string returned trom TestBean.toString(), and then the error goes away. When I try to do another insignificant change and build again, the error happens again. Does this mean it's actually a bug in the groovy plugin's interaction with the compiler? FWIW I have no such problems after changing my classes to use @Canonical instead of @Immutable.
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HulaBula added a comment -

I'm experiencing the same issue here. Spring STS 2.9, Groovy 1.8.6 and Java 7 (OpenJDK) on Ubuntu.
Adding @Immutable results in a NullPointerException and Eclipse shows an error in another groovy-class that's annotated with @ToString and @Validateable (grails).
Removing @Immutable lets everything work as normal again. Using other annotations (e.g. @Canonical) works fine..

Show
HulaBula added a comment - I'm experiencing the same issue here. Spring STS 2.9, Groovy 1.8.6 and Java 7 (OpenJDK) on Ubuntu. Adding @Immutable results in a NullPointerException and Eclipse shows an error in another groovy-class that's annotated with @ToString and @Validateable (grails). Removing @Immutable lets everything work as normal again. Using other annotations (e.g. @Canonical) works fine..
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Paul King added a comment -

Can anyone try with the latest versions of Eclipse/STS? Thanks.

Show
Paul King added a comment - Can anyone try with the latest versions of Eclipse/STS? Thanks.
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Paul King added a comment -

Is anyone still facing this problem or should I close it?

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Paul King added a comment - Is anyone still facing this problem or should I close it?
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Paul King added a comment -

Please reopen if you can reproduce this error - preferably standalone but with Eclipse if that is the only way. Ideally also with recent versions of Groovy and Eclipse.

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Paul King added a comment - Please reopen if you can reproduce this error - preferably standalone but with Eclipse if that is the only way. Ideally also with recent versions of Groovy and Eclipse.
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Youri Bonnaffé added a comment -

It is seems to be reproducible with Groovy Version: 2.1.3 JVM: 1.7.0_21 Vendor: Oracle Corporation OS: Linux
A sample snippet to reproduce it 

@groovy.transform.Immutable
class Person {
    def name
}

It was tested in demo by Guillaume Laforge himself

Show
Youri Bonnaffé added a comment - It is seems to be reproducible with Groovy Version: 2.1.3 JVM: 1.7.0_21 Vendor: Oracle Corporation OS: Linux A sample snippet to reproduce it @groovy.transform.Immutable class Person { def name } It was tested in demo by Guillaume Laforge himself
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Cedric Champeau added a comment -

Good catch. The NPE occurred when the type of a field is considered mutable (here, def is Object and the compiler cannot consider it immutable).

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Cedric Champeau added a comment - Good catch. The NPE occurred when the type of a field is considered mutable (here, def is Object and the compiler cannot consider it immutable).

People

  • Assignee:
    Cedric Champeau
    Reporter:
    Jan Stette
Vote (2)
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Dates

  • Created:
    Updated:
    Resolved: