[GROOVY-1687] One-arg methods have implicit default parameter of null

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Won't Fix
• Fix Version/s: 1.5.5
• Environment: v1.0 on Java 1.6.0 on WinXP prof edn
• Assignee: Jochen Theodorou
• Reporter: Gavin Grover
• Created: 31/Jan/07 10:30
• Updated: 14/Apr/08 06:33
• Resolved: 14/Apr/08 06:33

Description

When a method, whether static or instance, has one and only one parameter of non-primitive type, it has an implicit default value of null. Is this intended?

class A{
  static g2( Integer i ){ i }
  def g3( Integer i ){ i }
  static g4( int i ){ i }
  static g5( Integer i, Integer j ){ [ i, j ] }
}

//When no args supplied for one arg static method, default value of null assumed...
assert A.g2( new Integer(7) ) == 7
assert A.g2() == null

//Ditto for instance method...
assert new A().g3( new Integer(8) ) == 8
assert new A().g3() == null

//If parameter is primitive type, argument is mandatory as in Java...
assert A.g4( 7 ) == 7
try{ A.g4(); assert false }catch(Throwable e){ assert e instanceof IllegalArgumentException }

//When there's more than one parameter, both arguments also mandatory...
assert A.g5( new Integer(7), new Integer(8) ) == [ 7, 8 ]
try{ A.g5( new Integer(7) ); assert false }catch(Throwable e){ assert e instanceof MissingMethodException }
try{ A.g5(); assert false }catch(Throwable e){ assert e instanceof MissingMethodException }