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Ruby 2.6 raises exception for else without rescue

on July 10, 2018
This blog is part of our Ruby 2.6 series.

Ruby 2.6.0 was released on Dec 25, 2018.

Ruby 2.5

If we use else without rescue inside begin..end block in Ruby 2.5, it gives a warning.

1irb(main):001:0> begin
2irb(main):002:1> puts "Inside begin block"
3irb(main):003:1> else
4irb(main):004:1> puts "Inside else block"
5irb(main):005:1> end
6(irb):5: warning: else without rescue is useless

This warning is present as code inside else block will never get executed

Ruby 2.6

In Ruby 2.6 it will raise an exception if we use else without rescue in begin..end block. This commit changed warning into exception in Ruby 2.6. Changes made in the commit are experimental.

1irb(main):001:0> begin
2irb(main):002:1> puts "Inside begin block"
3irb(main):003:1> else
4irb(main):004:1> puts "Inside else block"
5irb(main):005:1> end
6Traceback (most recent call last):
71: from /usr/local/bin/irb:11:in `<main>'
8SyntaxError ((irb):3: else without rescue is useless)

The Chinese version of this blog is available here.


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