Feature #12063: KeyError#receiver and KeyError#name

• Status: Closed
• Assignee: -
• Target version: -

[ksss (Yuki Kurihara)]

I propose KeyError#receiver and KeyError#name (or KeyError#key) like NameError.

I think these method help to debug.
And will be able to find typo on did_you_mean gem.

See also https://github.com/yuki24/did_you_mean/pull/71

begin
  h = {foo: 1, bar: 2}
  h.fetch(:bax)
rescue KeyError => e
  p e.receiver #=> {foo: 1, bar: 2} equal `h`
  p e.name     #=> :bax
end

begin
  h = {foo: 1, bar: 2, baz: 3}
  h.fetch_values(:bar, :bax)
rescue KeyError => e
  p e.receiver #=> {foo: 1, bar: 2, baz: 3} equal `h`
  p e.name     #=> :bax
end

begin
  ENV.fetch("HOEM")
rescue KeyError => e
  p e.receiver #=> ENV
  p e.name     #=> "HOEM"
end

begin
  sprintf("%<foo>d", {fooo: 1})
rescue KeyError => e
  p e.receiver #=> {fooo: 1}
  p e.name     #=> :foo
end

[ksss (Yuki Kurihara)]

I made a patch https://github.com/ruby/ruby/pull/1251

[[e-mail] (ferdinand rosario)]

• Assignee set to core

[hsbt (Hiroshi SHIBATA)]

• Assignee deleted (core)

[matz (Yukihiro Matsumoto)]

Agreed.

Matz.

[ksss (Yuki Kurihara)]

Which method name is best?

"name" referenced from "NameError".
But I think, "key" is also good. Because this is "KeyError" method.

The patch on github is using "key".

Thanks.

[Eregon (Benoit Daloze)]

I think "name" is more consistent with other exceptions, such as NameError#name and NoMethodError#name (by inheritance).

[matz (Yukihiro Matsumoto)]

Keys may not be names (strings and symbols), so I think key is a sufficient name for the method.

Matz.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r59955.

---

error.c: KeyError#receiver and KeyError#key

• error.c: new method KeyError#receiver and KeyError#key.
  [Feature #12063]

• hash.c: make KeyError object with receiver and key.

• sprintf.c: ditto.

Author: ksss [e-mail]