respond_to? and protected methods
- by mlomnicki
It may not be so obvious how respond_to? works in ruby.
Consider that:
class A
def public_method
end
protected
def protected_method
end
private
def private_method
end
end
obj = A.new
obj.respond_to?(:public_method)
# true - that's pretty obvious
obj.respond_to?(:private_method)
# false - as expected
obj.respond_to?(:protected_method)
# true - WTF?
So if 'obj' responds to protected_method we should expect
obj.protected_method
not to raise an exception, shouldn't we?
...but it raises obviously
Documentation points that calling respond_to? with 2nd argument set to true check private method as well
obj.respond_to?(:private_method, true)
# true
And that's far more reasonable
So the question is how to check if object responds to public method only?
Is there a solution better than that?
obj.methods.include?(:public_method)
# true
obj.methods.include?(:protected_method)
# false
