Bug #9105: callcc による不整合(例:Hash)

• Status: Closed
• Assignee: -
• Target version: 2.1.0
• ruby -v: ruby 2.1.0dev (2013-11-11 trunk 43647) [x86_64-linux]
• Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN

[tarui (Masaya Tarui)]

=begin
以下のコードを実行すると、
equire 'continuation'
h = {1=>2,3=>4}
c = nil
f = false
h.each { callcc {|c2| c = c2 } }
unless f
f = true
c.call
end
h.each {|i| h.delete(1); p i}

以下のような結果になります。

[1, 2]
[false, false]
test.rb:10:in each': hash modified during iteration (RuntimeError) from test.rb:10:in '

[false, false]自体はst_foreach_checkで全く機能していない
/* call func with error notice */
retval = (*func)(0, 0, arg, 1);
を消せばいいのですが、
RuntimeErrorが発生するのはcallccによりhash_foreach_ensureの実行が2重に行われて、
RHASH_ITER_LEV(hash)の管理が破綻してしまっている為です。

他の所でも容易に起こりうると思うのですが、未調査です。
＆そもそもどう対処すべきでしょう？

=end

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r43675.
Masaya, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

hash.c: restore iter_lev

• hash.c (hash_foreach_ensure): restore iter_lev to the previous
  value, not just decrement. [ruby-dev:47803] [Bug #9105]

[nagachika (Tomoyuki Chikanaga)]

• Status changed from Closed to Open

r43675 はマルチスレッドで同一の Hash を使っている場合に RHASH_ITER_LEV(hash) の値が不正になることがあると思います。
以下のようなスクリプトを実行すると RHASH_ITER_LEV() が 0 に戻らなくなるので要素追加に失敗します。

h = {1=>2}
th1 = Thread.start{ h.each{ sleep 1 } }
sleep 0.1
th2 = Thread.start{ h.each { sleep 3 } }
th1.join
th2.join

h[5] = 6 # => can't add a new key into hash during iteration (RuntimeError)

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

This issue was solved with changeset r43683.
Masaya, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

hash.c: iteration level with reentering

• hash.c (hash_foreach_iter, hash_foreach_ensure, rb_hash_foreach):
  deal with iteration level when reentering by callcc. temporary
  measure until rollback of ensure is introduced. [ruby-dev:47807]
  [Bug #9105]

[nobu (Nobuyoshi Nakada)]

• Related to Bug #14472: `File::open` closes the file too early when used with callcc added