Enumerable#each_entry behaves differently from MRI

[toy]

Enumerable#each_entry is supposed to convert multiple arguments to an array, but the behaviour is different from MRI and jruby 1.7 when multiple arguments are yielded.

jruby -v:
jruby 9.0.5.0 (2.2.3) 2016-01-26 7bee00d Java HotSpot(TM) 64-Bit Server VM 24.76-b04 on 1.7.0_76-b13 +jit [linux-amd64]
jruby 9.1.5.0 (2.3.1) 2016-09-07 036ce39 Java HotSpot(TM) 64-Bit Server VM 24.76-b04 on 1.7.0_76-b13 +jit [linux-x86_64]

test file:

class Foo
  include Enumerable

  def each
    yield 1
    yield 1, 2
    yield
  end
end

out = []
Foo.new.each_entry{ |*args| out << args }
puts "each_entry: #{out.inspect}"

Expected output:

==[1.9.3-p551]==
each_entry: [[1], [[1, 2]], [nil]]

==[2.0.0-p648]==
each_entry: [[1], [[1, 2]], [nil]]

==[2.1.10]==
each_entry: [[1], [[1, 2]], [nil]]

==[2.2.6]==
each_entry: [[1], [[1, 2]], [nil]]

==[2.3.3]==
each_entry: [[1], [[1, 2]], [nil]]

==[2.4.0]==
each_entry: [[1], [[1, 2]], [nil]]

==[jruby-1.7.26]==
each_entry: [[1], [[1, 2]], [nil]]

jruby 9.x output:

==[jruby-9.0.5.0]==
each_entry: [[1], [1, 2], [nil]]

==[jruby-9.1.7.0]==
each_entry: [[1], [1, 2], [nil]]

[kares]

confirmed on latest 9K (9.1.8.0) as well: each_entry: [[1], [1, 2], [nil]]

[headius]

I pushed a possible fix. Feels like we are endlessly tweaking this logic back and forth.

I did try to do a Ruby implementation, and I don't think it's possible without extra logic to tell the kind of arguments passed in from each. If I implement each_entry as Ruby code, it behaves like JRuby.

~/projects/jruby $ cat blah.rb
class Foo
  include Enumerable

  def each
    yield 1
    yield 1, 2
    yield
  end

  def each_entry
    each {|*a| yield(*a)}
  end
end

out = []
Foo.new.each_entry{ |*args| out << args }
puts "each_entry: #{out.inspect}"

~/projects/jruby $ jruby blah.rb
each_entry: [[1], [1, 2], []]

[enebo]

@headius I commented on the PR but we seemingly changed all other yield calls in RubyEnumerable to yield from yieldSpecific already. This is the last one in that file. Glancing at other yieldSpecific in other files and they mostly seem ok since we know the argument we are passing internally.

[headius]

@enebo Ok, might as well go with it then.

[toy]

@headius each_entry is always yielding one argument, so 1 argument is passed as is, 2 or more arguments are converted to array and 0 arguments will yield nil. So your ruby implementation should be like:

def each_entry
  each {|*a| yield(a.size > 1 ? a : a[0])}
end