[GROOVY-8281] Final field is null in trait, but it has assigned value

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.8, 2.4.9, 2.4.10, 2.4.11, 2.4.12
• Fix Version/s: 2.5.1
• Assignee: Paul King
• Reporter: Dominik Przybysz
• Created: 08/Aug/17 09:55
• Updated: 26/Jul/18 04:38
• Resolved: 10/Jul/18 12:56

Description

I have a code like this:

trait MyTrait {
	final String myValue = "test"
	final Wrapper wrapper = new Wrapper(myValue)
}

class Wrapper {
	Wrapper(String value){
		if(value == null) {
			throw new Exception("Value is null!!!")	
		}
		println "OK: $value"
	}
}

class Main implements MyTrait {}

new Main()

Everything works as expected with groovy 2.4.7:

$ sdk u groovy 2.4.7

Using groovy version 2.4.7 in this shell.
$ groovy bug.groovy 
OK: test

but newer versions of groovy do not compile this code (2.4.8, 2.4.9, 2.4.10) or have null to value (2.4.11, 2.4.12):

$ sdk u groovy 2.4.8

Using groovy version 2.4.8 in this shell.
$ groovy bug.groovy 
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
~/bug.groovy: 3: Apparent variable 'myValue' 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 'myValue' but left out brackets in a place not allowed by the grammar.
 @ line 3, column 38.
   	final Wrapper wrapper = new Wrapper(myValue)
                                        ^

1 error

$ sdk u groovy 2.4.9

Using groovy version 2.4.9 in this shell.
$ groovy bug.groovy 
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
~/bug.groovy: 3: Apparent variable 'myValue' 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 'myValue' but left out brackets in a place not allowed by the grammar.
 @ line 3, column 38.
   	final Wrapper wrapper = new Wrapper(myValue)
                                        ^

~/bug.groovy: 3: Apparent variable 'myValue' 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 'myValue' but left out brackets in a place not allowed by the grammar.
 @ line 3, column 38.
   	final Wrapper wrapper = new Wrapper(myValue)
                                        ^

2 errors

$ sdk u groovy 2.4.10

Using groovy version 2.4.10 in this shell.
$ groovy bug.groovy 
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
~/bug.groovy: 3: Apparent variable 'myValue' 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 'myValue' but left out brackets in a place not allowed by the grammar.
 @ line 3, column 38.
   	final Wrapper wrapper = new Wrapper(myValue)
                                        ^

~/bug.groovy: 3: Apparent variable 'myValue' 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 'myValue' but left out brackets in a place not allowed by the grammar.
 @ line 3, column 38.
   	final Wrapper wrapper = new Wrapper(myValue)
                                        ^

2 errors

$ sdk u groovy 2.4.11

Using groovy version 2.4.11 in this shell.
$ groovy bug.groovy 
Caught: java.lang.Exception: Value is null!!!
java.lang.Exception: Value is null!!!
	at Wrapper.<init>(bug.groovy:9)
	at MyTrait$Trait$Helper.$init$(bug.groovy:3)
	at Main.<init>(bug.groovy)
	at bug.run(bug.groovy:17)
$ sdk u groovy 2.4.12

Using groovy version 2.4.12 in this shell.
$ groovy bug.groovy 
Caught: java.lang.Exception: Value is null!!!
java.lang.Exception: Value is null!!!
	at Wrapper.<init>(bug.groovy:9)
	at MyTrait$Trait$Helper.$init$(bug.groovy:3)
	at Main.<init>(bug.groovy)
	at bug.run(bug.groovy:17)

Issue Links

• is duplicated by: GROOVY-7515 static initializers on trait fields are discarded
• links to: GitHub Pull Request #772