Bug #16649: Object with [] method doesn't work as String#encode's fallback

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.8.0dev (2020-02-23T15:28:34Z master f88d209bb7) [x86_64-linux]
• Backport: 2.5: REQUIRED, 2.6: DONE, 2.7: DONE

[pocke (Masataka Kuwabara)]

String#encode document says fallback can be a Hash, a Proc, a Method or an object which has [] method.

Sets the replacement string by the given object for undefined character. The object should be a Hash, a Proc, a Method, or an object which has [] method
https://docs.ruby-lang.org/en/2.7.0/String.html#method-i-encode

But actually an object with [] does not work.

Reproduce:

class C
  def [](str)
    '!'
  end
end

str = "\u00b7\u2014"
p str.encoding # => #<Encoding:UTF-8>

# It works
p str.encode("Windows-31J", fallback: C.new.method(:[]))
# => "!!"

# It does not work
p str.encode("Windows-31J", fallback: C.new)
# => U+00B7 from UTF-8 to Windows-31J (Encoding::UndefinedConversionError)

[nobu (Nobuyoshi Nakada)]

• Backport changed from 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN to 2.5: REQUIRED, 2.6: REQUIRED, 2.7: REQUIRED

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|8b6e2685a4b7c7de905f7ed60c02ef85e0724754.

---

Fixed symbol misused as ID

rb_funcallv_public and rb_respond_to require an ID, not a
Symbol. [Bug #16649]

[naruse (Yui NARUSE)]

• Backport changed from 2.5: REQUIRED, 2.6: REQUIRED, 2.7: REQUIRED to 2.5: REQUIRED, 2.6: REQUIRED, 2.7: DONE

ruby_2_7 fa48a26d886d86469a0075d91d152252e9fc0c8c.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.5: REQUIRED, 2.6: REQUIRED, 2.7: DONE to 2.5: REQUIRED, 2.6: DONE, 2.7: DONE

backported into ruby_2_6 at r67901.