rails changed? method is always false - ruby-on-rails

Question

I am trying to check in my model if a checkbox value was changed or not. If it was changed I want my method set_ip_setting to run in before_save but my x variable is always coming back as false even if I change the value. Why is it coming back as always false? I don't see what I am doing wrong
before_save :set_ip_setting, if: :check_my_ip
def check_my_ip
x = self.sip.my_ip_changed?
is_ip = self.sip.my_ip
if x == true && is_ip == true
return false
elsif x == false && is_ip == true
return false
elsif x == true
return true
end
end
def set_ip_setting
if self.sip.try(:my_ip) == true
sip.nat = "yes"
sip.invite = "yes"
end
end
EDITED
I got my desired outcome by using previous_changes method but I think there is a cleaner way but here is what worked out for me
def check_my_ip
x = self.sip.previous_changes[:my_ip]
off_to_on = [false, true]
on_to_off = [true, false]
is_ip = self.sip.my_ip ? 1 : 0
if x.nil? && is_ip == 1
return false
elsif x == on_to_off
return false
end
return true
end

Answer 1

Generally you do not write if x == true. In Ruby, true and false are distinct values. For example, 1 == true is false.
Instead, simply check if x or if !x.
def check_my_ip
# Note that an explicit `self` is not necessary except when setting a value.
x = sip.my_ip_changed?
is_ip = sip.my_ip
if x && is_ip
return false
elsif !x && is_ip
return false
elsif x
return true
end
end
def set_ip_setting
if self.sip.try(:my_ip)
sip.nat = "yes"
sip.invite = "yes"
end
end
Your logic can be simplified, and implicit return used.
def check_my_ip
x = sip.my_ip_changed?
is_ip = sip.my_ip
if is_ip
false
elsif x
true
else
false
end
end