Pattern: Unnecessary null check
Issue: -
Groovy contains the safe dereference operator. It can be used in boolean conditional statements to safely replace explicit x == null tests. Also, testing the this or super reference for null equality is pointless and can be removed.
Examples of violations:
if (obj != null && obj.method()) { }
if (obj != null && obj.prop) { }
// this is pointless and won't avoid NullPointerException
if (obj.method() && obj != null ) { }
if (this == null) { }
if (null == this) { }
if (this != null) { }
if (null != this) { }
if (super == null) { }
if (null == super) { }
if (super != null) { }
if (null != super) { }Examples of acceptable code:
// null check it OK
if (obj != null) { }
// null safe dereference in if is OK
if (obj?.method()) { }
// null safe dereference in ternary is OK
(obj?.prop && obj?.prop2) ? x : y
// obj is reused in a parameter list, so OK
if (obj != null && obj.method() && isValid(obj)) { }
// rule is not so complex yet...
(obj != null && obj.prop && obj.method()) ? x : y