From: matz@... Date: 2017-04-17T06:50:25+00:00 Subject: [ruby-core:80724] [Ruby trunk Feature#13224] Add FrozenError as a subclass of RuntimeError Issue #13224 has been updated by matz (Yukihiro Matsumoto). OK, accepted. Matz. ---------------------------------------- Feature #13224: Add FrozenError as a subclass of RuntimeError https://bugs.ruby-lang.org/issues/13224#change-64276 * Author: jeremyevans0 (Jeremy Evans) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Currently, attempting to modify a frozen object leads to a `RuntimeError` exception. Unfortunately, this means it is not easy to differentiate exceptions raised from attempting to modify frozen objects from generic exceptions such as calling `Kernel#raise` with no exception class. The attached patch adds `FrozenError` as a subclass of `RuntimeError`, and uses `FrozenError` instead of `RuntimeError` for exceptions raised when there is an attempt to modify a frozen object. It should be backwards compatible in the sense that: ~~~ruby begin "a".freeze << b rescue RuntimeError end ~~~ Will still function as before. More people in the ruby community are starting to use frozen objects for the benefits of immutability (thread-safety, cache-ability, referential transparency), and having an exception class dedicated to misuse of frozen objects will make it easier to handle those exceptions. The attached patch is a little long, mostly because ruby's test suite is currently brittle in regards to handling exception classes. For example, `assert_raise(RuntimeError)` needs to be changed to `assert_raise(FrozenError)`, because `assert_raise` uses `instance_of?` instead of `kind_of?` if given an exception class and not a module. Both RSpec and recent versions of Minitest should automatically handle this type of change without code modifications. ---Files-------------------------------- 0001-Add-FrozenError-as-a-subclass-of-RuntimeError.patch (27.2 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: