Missing-Safe-Method.md

Missing Safe Method

Introduction

Candidate methods for the Missing Safe Method smell are methods whose names end with an exclamation mark.

An exclamation mark in method names means (the explanation below is taken from here):

The ! in method names that end with ! means, “This method is dangerous”—or, more precisely, this method is the “dangerous” version of an otherwise equivalent method, with the same name minus the !. “Danger” is relative; the ! doesn’t mean anything at all unless the method name it’s in corresponds to a similar but bang-less method name.

So, for example, gsub! is the dangerous version of gsub. exit! is the dangerous version of exit. flatten! is the dangerous version of flatten. And so forth.

Such a method is called Missing Safe Method if and only if the non-bang version does not exist and this method is reported as a smell.

Missing Safe Method was formerly known as Prima Donna Method.

Example

Given

class C
  def foo; end
  def foo!; end
  def bar!; end
end

Reek would report the Missing Safe Method smell for bar!, but not for foo!.

Reek reports this smell only in a class context, not in a module context in order to allow perfectly legit code like this:

class Parent
  def foo; end
end

module Dangerous
  def foo!; end
end

class Son < Parent
  include Dangerous
end

class Daughter < Parent
end

In this example, Reek would not report the Missing Safe Method smell for the method foo of the Dangerous module.

Configuration

Missing Safe Method offers the Basic Smell Options.

Example configuration via source comment

Imagine code like this:

class Alfa
  def bravo!
  end
end

This would report:

ruby.rb -- 1 warning: [1]:MissingSafeMethod: Alfa has missing safe method 'bravo!'

If you want to suppress this warning you can do this via source comment like this:

# :reek:MissingSafeMethod { exclude: [ bravo! ] }
class Alfa
  def bravo!
  end
end