[GROOVY-4334] Method parameter names missing in compiled classes when using parameter in closure

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 1.6.8
• Fix Version/s: 1.7.6, 1.8-beta-3
• Component/s: bytecode, Compiler
• Environment: Groovy 1.6.8, Windows XP 32Bit, Grails 1.2.2
• Assignee: Jochen Theodorou
• Reporter: Soenke Sothmann
• Created: 27/Jul/10 08:19
• Updated: 14/Dec/10 08:50
• Resolved: 14/Dec/10 08:50

Description

When you define a closure inside a method body, and inside the closure you directly access a method argument, parameter name of surrounding class is missing.

The parameter name of the method is correctly compiled into the class file if you assign the method parameter to a local variable and use this variable inside the closure.

This is a problem when you use Spring Security 3 to secure service methods.
I tried to annotate my groovy service method like this:

@PreAuthorize("hasPermission(#myArg, 'read')")
Bar getBarFromFoo3(Foo myArg) {
	def criteria =  Bar.createCriteria()
	List result = criteria {
		eq("foo", myArg)
		maxResults(1)
	}
	if (result.size() == 0) {
		return null
	}
	return result[0]
}

The annotation should protect the argument "myArg". Spring Security fails to secure this method because it cannot find the parameter named "myArg".
Decompiling the class file reveals:

@PreAuthorize("hasPermission(#myArg, 'read')")
public Bar getBarFromFoo3(Foo ???) {

the parameter name is missing (indicated by the three "?").

When I use a local variable for the parameter, it works:

@PreAuthorize("hasPermission(#myArg, 'read')")
Bar getBarFromFoo4(Foo myArg) {
	Foo localMyArg = myArg
	def criteria =  Bar.createCriteria()
	List result = criteria {
		eq("foo", localMyArg)
		maxResults(1)
	}
	if (result.size() == 0) {
		return null
	}
	return result[0]
}

Decompiling the class file reveals:

@PreAuthorize("hasPermission(#myArg, 'read')")
public Bar getBarFromFoo4(Foo myArg) {

Here you can see that the parameter name is correctly compiled into the class file.

You can see this using a decompiler like JD (http://java.decompiler.free.fr/?q=jdgui#downloads).