Bug #21882: IO::Buffer#locked leaves the buffer locked when the block raises

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 4.0.1 (2026-01-13 revision e04267a14b) +PRISM [x86_64-linux]
• Backport: 3.3: REQUIRED, 3.4: DONE, 4.0: DONE

[hanazuki (Kasumi Hanazuki)]

IO::Buffer#locked should unlock the buffer even after the block raises an exception.

buf = IO::Buffer.new(100)
buf.locked { fail } rescue nil
buf.locked { p :ok }  # expected to print :ok, but actually raises a LockedError

[hanazuki (Kasumi Hanazuki)]

Patch: https://github.com/ruby/ruby/pull/16180

[nobu (Nobuyoshi Nakada)]

buf.locked {break} also leaves it locked.
Could you add a test for this case too?

[hanazuki (Kasumi Hanazuki)]

Thank you for your review, nobu. I added test cases for break and throw.

[hanazuki (Kasumi Hanazuki)]

• Status changed from Open to Closed

Applied in changeset git|b5ccab2093c9bb19ae8564a935e6fd72ec7354cc.

---

IO::Buffer#locked: Release lock even when the block raises (#16180)

IO::Buffer#locked: Release lock even when the block raises/breaks

Previously, IO::Buffer#locked leaks the lock when the block raises
an exception, or breaks.

Fixes: [Bug #21882]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN to 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED to 3.3: REQUIRED, 3.4: DONE, 4.0: REQUIRED

ruby_3_4 9f6c39510b213c71e039b7499ff6b8a0535e9b19 merged revision(s) b5ccab2093c9bb19ae8564a935e6fd72ec7354cc.

[rwstauner (Randy Stauner)]

Backport PR for ruby_4_0 (4.0) opened: https://github.com/ruby/ruby/pull/17513

[k0kubun (Takashi Kokubun)]

• Backport changed from 3.3: REQUIRED, 3.4: DONE, 4.0: REQUIRED to 3.3: REQUIRED, 3.4: DONE, 4.0: DONE

ruby_4_0 commit:2bf4c08b84242bf5030c4088842e72f57f37f781 merged revision(s) b5ccab2093c9bb19ae8564a935e6fd72ec7354cc, commit:2bf4c08b84242bf5030c4088842e72f57f37f781.