This rule applies whenever an if statement is followed by one or more else if statements; the final else if should be followed by an else statement.

The requirement for a final else statement is defensive programming.

The else statement should either take appropriate action or contain a suitable comment as to why no action is taken. This is consistent with the requirement to have a final default clause in a switch statement.

Noncompliant Code Example

if (condition1) {
  do_something();
} else if (condition2) {
  do_something_else();
}

Compliant Solution

if (condition1) {
  do_something();
} else if (condition2) {
  do_something_else();
} else {
  throw new InvalidArgumentException('message');
}

See