Bug #13817: test/unit breaks Hash

• Status: Closed
• Assignee: ktsj (Kazuki Tsujimoto)
• Target version: -
• ruby -v: ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]
• Backport: 2.2: REQUIRED, 2.3: DONE, 2.4: DONE

[rovf (Ronald Fischer)]

Consider the following program:

#!/usr/bin/env ruby
BEGIN {$VERBOSE = true}
require 'test/unit'
class Hash
  STDERR.puts method_defined?(:<<)
  alias << merge!
  STDERR.puts method_defined?(:<<)
end

In older Ruby versions (1.9.3, 2.3.3), the output of this program was:

false
true

In Ruby 2.4.1, the output is

false
~/work/stash/vp5/src/test/test_xx.rb:6: warning: method redefined; discarding old <<
true

Please note:

1. The warning occurs, even though method_defined? tells us that no << method is in Hash.
2. The warning disappears, when we do not require test/unit, which suggests that the problem is caused by test/unit
3. Changing the offending line to alias :<< :merge! does not make any difference

[kou (Kouhei Sutou)]

• Status changed from Open to Third Party's Issue
• Assignee set to ktsj (Kazuki Tsujimoto)

It's not caused by test-unit. It's caused by power_assert.

Please report it to https://github.com/k-tsj/power_assert/issues/new with the following script:

#!/usr/bin/env ruby
$VERBOSE = true
require 'power_assert/enable_tracepoint_events'
class Hash
  STDERR.puts method_defined?(:<<)
  alias << merge!
  STDERR.puts method_defined?(:<<)
end

[rovf (Ronald Fischer)]

Bug reported at https://github.com/k-tsj/power_assert/issues/19

[kou (Kouhei Sutou)]

Great!

[wanabe (_ wanabe)]

• Related to Bug #11182: Refinement with alias causes strange behavior added

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Status changed from Third Party's Issue to Open
• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.2: REQUIRED, 2.3: REQUIRED, 2.4: REQUIRED

It's a ruby's bug.
"old <<" means a refined method, but it is not redefined actually.

class C
  def t; :t; end
  def f; :f; end
end

module M
  refine C do
    alias foo t
  end
end

class C
  alias foo f
end

using M
p C.new.foo #=> :t

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r59613.

---

vm_method.c: alias warning at refined method

• vm_method.c (rb_method_entry_make): suppress a warning at
  refined method which will not be redefined.
  [ruby-core:82385] [Bug #13817]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: REQUIRED, 2.3: REQUIRED, 2.4: REQUIRED to 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE

ruby_2_4 r59819 merged revision(s) 59613.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE to 2.2: REQUIRED, 2.3: DONE, 2.4: DONE

ruby_2_3 r59880 merged revision(s) 59613.