Bug #11247: Should position of `using` affect the behavior?

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: -
• ruby -v: ruby 2.3.0dev (2015-06-11 trunk 50798) [x86_64-linux]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN

[ko1 (Koichi Sasada)]

The following script makes two refinements refine class C.

class C
  def foo
    p C
  end
end

module R1
  refine C do
    def foo
      p R1
      super
    end
  end
end

module R2
  refine C do
    def bar
      C.new.foo
    end

    using R1

    def baz
      C.new.foo
    end
  end
end

using R2

C.new.bar
C.new.baz

R2 refines C with methods bar and baz. The difference is the place of using. bar is located before using and baz is after.

Recent fix changed behavior of this script.

• trunk in May: C and R1, C
• current trunk: R1, C and R1, C

This change is caused by sharing CREF between methods in same CREF scope. It reduce memory consumption (before this fix, we need one CREF per one method).

Is it acceptable change or unacceptable?

[shugo (Shugo Maeda)]

• Status changed from Open to Assigned
• Assignee changed from shugo (Shugo Maeda) to ko1 (Koichi Sasada)

Koichi Sasada wrote:

Recent fix changed behavior of this script.

• trunk in May: C and R1, C
• current trunk: R1, C and R1, C

This change is caused by sharing CREF between methods in same CREF scope. It reduce memory consumption (before this fix, we need one CREF per one method).

Is it acceptable change or unacceptable?

It's unacceptable. CREF should be copied at least when refinements are activated in the context.

[ko1 (Koichi Sasada)]

Okay, I'll fix it.
(I need to remember code about it...)

[ko1 (Koichi Sasada)]

• Status changed from Assigned to Closed

Applied in changeset r52677.

---

• vm.c (rb_vm_cref_replace_with_duplicated_cref): added.

  CREFs should not be shared by methods between `using'.
  [Bug #11247]

• vm_insnhelper.c (vm_cref_replace_with_duplicated_cref): ditto.

• vm.c (vm_cref_dup): should copy refinements correctly.

• eval.c: use rb_vm_cref_replace_with_duplicated_cref().

• eval_intern.h: add a decl. of
  rb_vm_cref_replace_with_duplicated_cref().

• vm_eval.c (eval_string_with_cref): do not need to pass
  scope's CREF because VM can find out CREF from stack frames.

• test/ruby/test_refinement.rb: add a test.