DevMeeting-2022-12-15

https://bugs.ruby-lang.org/issues/19170

DateTime and location

• 2022/12/15 (Thu) 13:00-17:00 JST @ Online

Next Date

• 2023/01/19 (Thu) 13:00-17:00 JST @ Online

Announce

About release timeframe

Ordinary tickets

[Misc #19178] Distribution of Ruby and Standard Library gems. (ioquatix)

• Not sure what to discuss

[Feature #19134] ** is not allowed in def foo(...) (ko1/shugo)

[Feature #19165] Method (with no param) delegation with *, **, and … is slow (ko1/shugo)

# fast
ruby2_keywords def foo(*args)
  bar(*args)
end

# slow both in 3.1 and 3.2 (1)
def foo(*args, **kwargs)
  bar(*args, **kwargs)
end

# fast in 3.1, slow in 3.2 (2)
def foo(...)
  bar(...)
end

• https://bugs.ruby-lang.org/issues/19134 caused (2)
• ko1’s improvement will improve both (1) and (2)
  • But it requires modification of MJIT and YJIT (and TypeProf)

def foo(*args, **kwargs)
  bar(*args, k1: 1, **kwargs, k2: 2)
end

def foo(*, **)
  bar(*, k1: 1, **, k2: 2)
end

def foo(...)
  bar(...)
end

def foo(...)
  bar(*, k1: 1, **, k2: 2)
end

[#19230]

• Discussion 1: def foo(...); bar(**); end should be allowed?
  • def foo(...); bar(*); end is allowed from master, so we have no compat. issue if we prohibit them.
  • def foo(...); bar(&); end is working on Ruby 3.1 so it will be compat. issue if we prohibit them.

  • def f(...) # ... is syntactic sugar to *, **, & ?
      g(*)                 # prohibited
      h(**)                # prohibited
      i(*, new_key: 1, **) # prohibited
      j(&)                 # works as Ruby 3.1
    end
    
    def f(&)
      j(&)
    end
    
    def f(*, **) # "no problem" by Matz
      g(*)
      g2(*, *)
      h(**)
      i(*, new_key: 1, **)
    end
    

  • matz: ok, I have no reason to allow them. Conclusion is written in the above code comments.
• Disucssion 2: RubyVM::AST parses def foo(...) and returns [*, &]. Should we return [*, **, &] ?
  • def foo(...) uses ruby2_keywords and it returns [*, &].
  • Shugo’s patch doesn’t use ruby2_keywords so it returns [*, **, &], but it has some slowdown.

  • def foo(...)
    end
    method(:foo).parameters #=> [[:rest, :*], [:keyrest, :**], [:block, :&]]
    

  • shugo: before my patch, MRI has a flag to represent ....
  • matz: choose [*, &] for Ruby 3.2 to keep the compatibility. No need to show the ... flag. In a long term, RubyVM::AST should return ...
• Discussion 3: Should we merge https://github.com/ruby/ruby/pull/6920 to Ruby 3.2?
  • Performance penalty is fixed.
  • def foo(*, **); bar(*, **); end is also improved.
  • YJIT and MJIT should be supported but no time for Ruby 3.2.0
    • MJIT has no problem
    • YJIT seems have some
  • shugo: def f(...) is not slow because the implementation will be backed, so the importance of this patch is not high.
  • matz: Ok, try it on Ruby 3.3.
• Other point: Should we prohibit it? (caused by implmenetation details)

  • def f(*, **, &)
      p(...)
    end
    f 1, 2, k:1
    # 1
    # 2
    # {:k=>1}
    

  • matz: ok, prohibit it.

Conclusion:

• Prohibit bar(*) in def foo(...) as Ruby 3.1
  • should be implemented
• Prohibit bar(...) in def foo(*, **, &) as Ruby 3.1
  • should be implemented
• Prohibit bar(**) in def foo(...) as Ruby 3.1
  • by reverting shugo’s patch
• RubyVM::AST should return [*, &] against def foo(...) as Ruby 3.1
  • by reverting shugo’s patch
• ko1’s improvement will be merged for Ruby 3.3

Fix the count of encodings

ko1: naruse-san, can I implement it for Ruby 3.2? And how many is the limit? martin: 1024 is too many naruse: 256?

IRB maintainer

k0kubun: reline is now maintained by ima1zumi-san and hasumikin-san k0kubun: How about the status of irb maintainer?

[Feature #18033] Time.new to parse a string (nobu)

• matz: looks like samuel and eregon are against the API Time.new
• a_matsuda: I want this API asap for Rails development

• matz: okay

• matz: BTW, is this intentional?

irb(main):001:0> Time.new(0)
=> 0000-01-01 00:00:00 +091859

irb(main):021:0> Time.new(1887)
=> 1887-01-01 00:00:00 +091859
irb(main):022:0> Time.new(1888)
=> 1888-01-01 00:00:00 +0900

special variables

$, # Array#join($,)
$/ # Kernel#gets
$\ # Kernel#print
$; # String#split

ary.join      # == ary.join($,)
ary.join(nil) # == current: ary.join($,), desire: ary.join("")

Review of all logs of dev-meeting 2022

https://github.com/ruby/dev-meeting-log