Bug #19464: YJIT miscompiles `BasicObject#__send__` to alias methods of `send`

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONE

[alanwu (Alan Wu)]

Symptoms first experienced and reported by users of the kt-paperclip gem.
Reproducer:

klass = Class.new do
  class << self
    alias_method :my_send, :send

    def bar = :ok

    def foo = bar
  end
end

with_break = -> { break klass.send(:my_send, :foo) }
wo_break = -> { klass.send(:my_send, :foo) }

31.times { with_break[]; wo_break[] }

Fix: https://github.com/ruby/ruby/pull/7377

[alanwu (Alan Wu)]

• Description updated (diff)

[alanwu (Alan Wu)]

• Status changed from Open to Closed

Applied in changeset git|0eb634ae73cb327ede833b72492f912792a4a9d5.

---

YJIT: Detect and reject send(:alias_for_send, :foo)

Previously, YJIT failed to put the stack into the correct shape when
BasicObject#send calls an alias method for the send method itself.
This can manifest as strange NoMethodErrors in the final non-send
receiver, as seen with the kt-paperclip gem. I also found a case
where it makes YJIT fail the stack size assertion while compiling
leave.

YJIT's BasicObject#__send__ implementation already rejects sends to
send, but didn't detect sends to aliases of send. Adjust the
detection and reject these cases.

Fixes [Bug #19464]

[alanwu (Alan Wu)]

• Subject changed from YJIT miscompiles `BasicObject#send` to alias methods of `send` to YJIT miscompiles `BasicObject#__send__` to alias methods of `send`

[naruse (Yui NARUSE)]

• Backport changed from 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: REQUIRED to 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONE

ruby_3_2 b73a07359758a9034996752e981e09ddaffe8d87 merged revision(s) 0eb634ae73cb327ede833b72492f912792a4a9d5.