[ruby-core:119637] Behavior of raising from rescue blocks when multiple rescue blocks exist

[Rodrigo Rosenfeld Rosas via ruby-core <ruby-core@ml.ruby-lang.org>]

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Hello, I couldn't find any documentation about the subject, so I thought
this behavior should be probably documented.

Given the following code:

def raise_error
  raise "runtime error message"
rescue => e
  "StandardError: #{e.message}"
rescue RuntimeError => e
  puts "RuntimeError raised: #{e.message}"
  raise StandardError, "standard error message"
end

# same, but the order of the rescue blocks are inverted
def raise_error2
  raise "runtime error message"
rescue RuntimeError => e
  puts "RuntimeError raised: #{e.message}"
  raise StandardError, "standard error message"
rescue => e
  "StandardError: #{e.message}"
end

p ["raise_error", raise_error ]

begin
  p ["raise_error2", raise_error2]
rescue => e
  puts "raise_error2 raised: #{e.message}"
end

When we run it, this is the output in Ruby 3.3.5:

["raise_error", "StandardError: runtime error message"]

RuntimeError raised: runtime error message

raise_error2 raised: standard error message


In the first case (raise_error), the code raised from the RuntimeError
rescue block is rescued by the StandardError block, but when inverting the
order of the rescue blocks (raise_error2) then this won't happen.

Is this part of the specs? Is this behavior documented somewhere? Could
this behavior differ in different Ruby implementations and versions? Or can
we rely on such behavior?


This chapter doesn't include such case in its examples:

https://ruby-doc.com/docs/ProgrammingRuby/html/tut_exceptions.html

Or this documentation about Exceptions:

https://ruby-doc.org/3.3.5/syntax/exceptions_rdoc.html

Is there a recommended way for wrapping exceptions into a particular one
and then handling that exception from within the same method rescue blocks?
Or is this considered a bad practice?

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