[GROOVY-7075] Safe Navigation operator does not perform null check with @CompileStatic on interface type not declaring getter

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.3.6
• Fix Version/s: 2.3.7
• Component/s: Static compilation
• Assignee: Cédric Champeau
• Reporter: Jason Winnebeck
• Created: 17/Sep/14 09:21
• Updated: 19/Oct/15 16:53
• Resolved: 24/Sep/14 08:14

Description

The following code produces NullPointerException when compiled static, but operates as expected when running in dynamic groovy:

import groovy.transform.CompileStatic
@Grapes(
  @Grab(group='org.springframework.security', module='spring-security-core', version='3.2.5.RELEASE')
)
import org.springframework.security.core.context.SecurityContextHolder

@CompileStatic
def checkSafeNavi() {
  println SecurityContextHolder
  //class org.springframework.security.core.context.SecurityContextHolder
  println SecurityContextHolder.context
  //org.springframework.security.core.context.SecurityContextImpl@ffffffff: Null authentication
  println SecurityContextHolder.context?.authentication
  //null
  println SecurityContextHolder.context?.authentication?.name
  //NullPointerException
}

checkSafeNavi()

Thanks to Thibault Kruse for producing a minimal reproducible version.

Here is another test case that doesn't use Spring Security or any other dependency. This hopefully should be able to be transformed directly into a unit test for Groovy:

//If Y was a class implementing YParent, it works
//If Y had the getValue method directly, it works
//If Y redeclares (overrides) getValue, it works
interface Y extends YParent {
}

interface YParent {
 int getValue()
}

@groovy.transform.CompileStatic
def check() {
  Y y = null
  println y?.value
}

check()