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rubyerror-handlingrescue

what does "rescue false" mean inside if condition in ruby

I am ruby newbie and have one question.

if (new_account.save rescue false)
   # when account save success
else
   # when account save has error
end

I am not sure what rescue false means in this code. Thanks

Solution

  • A one-line rescue is syntactic sugar

    foo.bar rescue false
# same as
begin
  foo.bar
rescue
  false
end

    So your code is pretty much the same as this

    result = nil
begin
  result = new_account.save
rescue
  result = false
end

if result
  # when account save success
else
  # when account save has error
end

    The rescue false means that an exception thrown inside new_account.save is treated the same as it returning false. In my opinion, this is bad design. new_account is clearly designed to have two different failure cases, but the calling code ignores it. This code is extremely likely to hide actual bugs occurring inside the saving method.