Styjun

I've got an error in some child class:

(byebug) e.class
CSV::MalformedCSVError
(byebug) e.message.truncate(150, omission: '')
"Illegal quoting in line 1. [SmarterCSV: csv line 1]"
(byebug) e
#<CSV::MalformedCSVError: Illegal quoting in line 1. [SmarterCSV: csv line 1]>
(byebug) raise e.class, e.message.truncate(150, omission: '')
*** ArgumentError Exception: wrong number of arguments (given 1, expected 2)

I want to send the original error class and message to a further class, to rescue all of them without the creation of custom error for each child class (ChildClassError = Class.new(StandardError)).

I will be grateful for the help. I would like to understand the reason.

What's wrong here?

rescue StandardError => e
 raise e.class
end
*** ArgumentError Exception: wrong number of arguments (given 0, expected 2)

The issue is with CSV::MalformedCSVError#new violating the standard for the exceptions that Kernel#raise expects.

The latter attempts to call Exception#new/1 while the only possible arity of the constructor of CSV::MalformedCSVError is two. You should create an object yourself:

raise CSV::MalformedCSVError.new(e.message.truncate(150, omission: ''), __LINE__)

For the generic case, you probably should get the arity of the constructor and behave correspondingly.

You could do so by just rescuing from StandardError exception like so:

class Foo
 attr_reader :value
 def initialize(value)
 @value = value
 end
end

begin
 foo = Foo.new
rescue StandardError => e
 raise e.class.new(e.message.truncate(150, omission: ''))
end

Though this way, you're reinitializing another object of the same class here with a new/modified message.

Edit: Aleksei made a good point on arity, as a custom error/exception classes are made differently to have fine-grained control over the exceptions that are helpful while debugging. Make sure you have the right arity otherwise you'd be on a goose hunt than solving actual problem.