Bug #13391: wrong number of arguments error for Hash#map when lambda given

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: -
• ruby -v: ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin15]
• Backport: 2.2: DONTNEED, 2.3: DONTNEED, 2.4: DONE

[tomog105 (Tomohiro Ogoke)]

内容

Ruby 2.4.1 にて Hash オブジェクトの #map に 2つの引数を受け取る lambda を渡した際、
arguments error が発生します。

Ruby 2.4.0, ないし 2.3.4 では同じコードを実行した際にはエラーは発生していませんでしたが、
trunk でも同じエラーが発生します。

再現コード

% cat lambda.rb
hash = { a: 'hoge', b: 'fuga' }
lambda = -> (k, v) { p "#{k}:#{v}" }
hash.map(&lambda)

実行結果

% ruby -v lambda.rb
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin15]
lambda.rb:2:in `block in <main>': wrong number of arguments (given 1, expected 2) (ArgumentError)
	from lambda.rb:3:in `each'
	from lambda.rb:3:in `map'
	from lambda.rb:3:in `<main>'

% RBENV_VERSION=2.5.0-dev ruby -v lambda.rb
ruby 2.5.0dev (2017-03-31 trunk 58224) [x86_64-darwin15]
	from lambda.rb:3:in `<main>'
	from lambda.rb:3:in `map'
	from lambda.rb:3:in `each'
lambda.rb:2:in `block in <main>': wrong number of arguments (given 1, expected 2) (ArgumentError)

% RBENV_VERSION=2.4.0 ruby -v lambda.rb
ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin15]
"a:hoge"
"b:fuga"

% RBENV_VERSION=2.3.4 ruby -v lambda.rb
ruby 2.3.4p301 (2017-03-30 revision 58214) [x86_64-darwin15]
"a:hoge"
"b:fuga"

また、 #map ではなく #each を使う場合には、同じ lambda ブロックを渡した際でもエラーにはなりません。

% cat lambda_each.rb
hash = { a: 'hoge', b: 'fuga' }
lambda = -> (k, v) { p "#{k}:#{v}" }
hash.each(&lambda)

% ruby -v lambda_each.rb
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin15]
"a:hoge"
"b:fuga"

% RBENV_VERSION=2.5.0-dev ruby -v lambda_each.rb
ruby 2.5.0dev (2017-03-31 trunk 58224) [x86_64-darwin15]
"a:hoge"
"b:fuga"

[nobu (Nobuyoshi Nakada)]

• Related to Bug #12705: yielding args to a lambda uses block/proc rather than lambda/method semantics added

[nobu (Nobuyoshi Nakada)]

進捗です。
https://github.com/nobu/ruby/tree/bug/13391-map-arity

[nobu (Nobuyoshi Nakada)]

• Has duplicate Bug #13404: Hash#any? yields arguments to lambdas with proc semantics added

[hsbt (Hiroshi SHIBATA)]

• Status changed from Open to Assigned
• Assignee set to ko1 (Koichi Sasada)

ko1

Please review https://github.com/ruby/ruby/compare/trunk...nobu:bug/13391-map-arity

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed

Applied in changeset trunk|r59358.

---

vm_eval.c: rb_lambda_call

• enum.c (enum_collect): make the block arity same as the given
  block. [Bug #13391]

• internal.h (vm_ifunc): store arity instead of unused id.

• proc.c (rb_vm_block_min_max_arity): return ifunc arity.

• vm_eval.c (rb_lambda_call): call method with lambda block.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: REQUIRED to 2.2: DONTNEED, 2.3: DONTNEED, 2.4: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: DONTNEED, 2.3: DONTNEED, 2.4: REQUIRED to 2.2: DONTNEED, 2.3: DONTNEED, 2.4: DONE

ruby_2_4 r59500 merged revision(s) 59357,59358.