Bug #17386: Refinements break prepend

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: -
• ruby -v: ruby 3.0.0dev (2020-12-10T22:40:29Z master 6b1d2de6cc) [x86_64-darwin19]
• Backport: 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED

[shugo (Shugo Maeda)]

Reported in https://bugs.ruby-lang.org/issues/17379#note-5, but it seems a different issue from #17379 because Ruby 2.7.2 or earlier is not affected.

excelsior:/tmp$ cat t.rb
class Foo
  def foo
    p :hello
  end
end

module Code
  def foo
    p :A
  end
end

module Extension
  refine Foo do
    prepend Code
  end
end

Foo.new.foo unless ENV['SKIP'] # => :hello (ok)
Foo.prepend Code
Foo.new.foo     # => depends (not ok)
excelsior:/tmp$ ruby -v t.rb
ruby 3.0.0dev (2020-12-10T22:40:29Z master 6b1d2de6cc) [x86_64-darwin19]
:hello
:hello
excelsior:/tmp$ SKIP=t ruby -v t.rb
ruby 3.0.0dev (2020-12-10T22:40:29Z master 6b1d2de6cc) [x86_64-darwin19]
:A
excelsior:/tmp$ RBENV_VERSION=2.7.2 ruby -v t.rb
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin19]
:hello
:A
excelsior:/tmp$ SKIP=t RBENV_VERSION=2.7.2 ruby -v t.rb
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin19]
:A

[shugo (Shugo Maeda)]

• Subject changed from Refinements breaks prepend to Refinements break prepend

[shugo (Shugo Maeda)]

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

@ko1 (Koichi Sasada)
It seems that the following commit changed the behavior.
Could you check it?

b9007b6c548f91e88fd3f2ffa23de740431fa969 is the first bad commit
commit b9007b6c548f91e88fd3f2ffa23de740431fa969
Author: Koichi Sasada <[e-mail]>
Date:   Wed Jan 8 16:14:01 2020 +0900

    Introduce disposable call-cache.

    This patch contains several ideas:

    (1) Disposable inline method cache (IMC) for race-free inline method cache
        * Making call-cache (CC) as a RVALUE (GC target object) and allocate new
          CC on cache miss.
        * This technique allows race-free access from parallel processing
          elements like RCU.
    (2) Introduce per-Class method cache (pCMC)
        * Instead of fixed-size global method cache (GMC), pCMC allows flexible
          cache size.
        * Caching CCs reduces CC allocation and allow sharing CC's fast-path
          between same call-info (CI) call-sites.
    (3) Invalidate an inline method cache by invalidating corresponding method
        entries (MEs)
        * Instead of using class serials, we set "invalidated" flag for method
          entry itself to represent cache invalidation.
        * Compare with using class serials, the impact of method modification
          (add/overwrite/delete) is small.
        * Updating class serials invalidate all method caches of the class and
          sub-classes.
        * Proposed approach only invalidate the method cache of only one ME.

    See [Feature #16614] for more details.

[ko1 (Koichi Sasada)]

• Status changed from Assigned to Closed

Applied in changeset git|cee02d754d76563635c1db90d2ab6c01f8492470.

---

fix refinements/prepend bug

replaced method entry should be invalidated.
[Bug #17386]