groovy

Using log variable created with @Log or @Log4j causes compiler error if used in static method

Details

  • Type: Bug Bug
  • Status: Closed Closed
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: 1.8-beta-3
  • Fix Version/s: 1.8-rc-1, 1.9-beta-1
  • Component/s: None
  • Labels:
    None
  • Number of attachments :
    0

Description

If I have a class with it and use the 'log' variable in a static method I get a compilation error.

Log4jTest.groovy:
import groovy.util.logging.Log4j

@Log4j
class TestLog4j {

public static void main(String[] args)

{ log.info "Hello World" }

}

Error Message:
Apparent variable 'log' was found in a static scope but doesn't refer to a local variable, static field or class. Possible causes:
You attempted to reference a variable in the binding or an instance variable from a static context.
You misspelled a classname or statically imported field. Please check the spelling.
You attempted to use a method 'log' but left out brackets in a place not allowed by the grammar.

Activity

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Kurt Rush added a comment -

I am not sure if this is related but here is a blog that describes the same problem and his attempt to fix. But his fix does not work either (you will get a NPE if you use his).

http://enfranchisedmind.com/blog/posts/with-log-groovy-ast-transform/

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Kurt Rush added a comment - I am not sure if this is related but here is a blog that describes the same problem and his attempt to fix. But his fix does not work either (you will get a NPE if you use his). http://enfranchisedmind.com/blog/posts/with-log-groovy-ast-transform/
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Guillaume Laforge added a comment -

The logger injected in the classes is a field, but not a static one, hence why you're seeing this error message.
So should the logger be a static field instead? I think that's the question to ask.

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Guillaume Laforge added a comment - The logger injected in the classes is a field, but not a static one, hence why you're seeing this error message. So should the logger be a static field instead? I think that's the question to ask.
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Kurt Rush added a comment -

I think it should be static for several reasons. First it is a defacto Java standard to have a static logger variable and I think most Java devs would expect it to be that way. So anyone coming from the Java world would be surprised that it was not static. Secondly, the non-static version does not work in one important use case which is inside the main() function.

Is there any reason for it to not be static?

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Kurt Rush added a comment - I think it should be static for several reasons. First it is a defacto Java standard to have a static logger variable and I think most Java devs would expect it to be that way. So anyone coming from the Java world would be surprised that it was not static. Secondly, the non-static version does not work in one important use case which is inside the main() function. Is there any reason for it to not be static?
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Cedric Champeau added a comment - - edited

Guillaume, the injected field is static, but the compiler fails before the phase where the field is injected. It fails at semantic analysis where the field is injected at canonicalization. Changing from 

@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class LogASTTransformation implements ASTTransformation {

to

@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
public class LogASTTransformation implements ASTTransformation {

solves the problem. I'm not sure why the original transform phase is CANONICALIZATION though.
[update] Changing the phase doesn't break any test. If the phase is important, there should be test cases for that.

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Cedric Champeau added a comment - - edited Guillaume, the injected field is static, but the compiler fails before the phase where the field is injected. It fails at semantic analysis where the field is injected at canonicalization. Changing from @GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION) public class LogASTTransformation implements ASTTransformation { to @GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS) public class LogASTTransformation implements ASTTransformation { solves the problem. I'm not sure why the original transform phase is CANONICALIZATION though. [update] Changing the phase doesn't break any test. If the phase is important, there should be test cases for that.
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Guillaume Laforge added a comment -

Yup, I've changed the compile phase and noticed things were fine too.
I haven't added tests yet though.
I'm wondering if there were some reason for the canonicalization phase for being chosen though.

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Guillaume Laforge added a comment - Yup, I've changed the compile phase and noticed things were fine too. I haven't added tests yet though. I'm wondering if there were some reason for the canonicalization phase for being chosen though.
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Guillaume Laforge added a comment -

So it looks like the Log transformation happens in canonicalization phase, which is after the semantic analysis phase where the static verifier kicks in, and throws the exception you've been seeing.

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Guillaume Laforge added a comment - So it looks like the Log transformation happens in canonicalization phase, which is after the semantic analysis phase where the static verifier kicks in, and throws the exception you've been seeing.
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Guillaume Laforge added a comment -

Weird, my comment didn't get through initially... hmmm... the JIRA mysteries...

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Guillaume Laforge added a comment - Weird, my comment didn't get through initially... hmmm... the JIRA mysteries...
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Sandro Martini added a comment -

Hi all,
sorry but I think the issue is still valid (at least for the @Log annotation, my use case).
I'm using Groovy-1.8.2 (from latest eclipse plugin) and I have the same error described here.
Tell me if you need another ticket (I'm not able to reopen this).

Thanks,
Sandro

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Sandro Martini added a comment - Hi all, sorry but I think the issue is still valid (at least for the @Log annotation, my use case). I'm using Groovy-1.8.2 (from latest eclipse plugin) and I have the same error described here. Tell me if you need another ticket (I'm not able to reopen this). Thanks, Sandro

People

  • Assignee:
    Guillaume Laforge
    Reporter:
    Kurt Rush
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