DevMeeting-2022-03-17

https://bugs.ruby-lang.org/issues/18591

DateTime and location

2022/03/17 (Thu) 13:00-17:00 JST @ Online

Next Date

2022/04/21 (Thu) 13:00-17:00 JST @ Online

Announce

About release timeframe

3.2.0 preview 1: in progress

Check security tickets

[secret]

Ordinary tickets

[Feature #18598] Add String#bytesplice (shugo)

I withdrew the proposal of String#bytesplice in #13110 because it may cause problems if the specified offset does not land on character boundary. But how about to raise IndexError in such cases?

# encoding: utf-8

s = "あいうえおかきくけこ"
s.bytesplice(9, 6, "xx")
p s #=> "あいうxxかきくけこ"
s.bytesplice(2, 3, "x") #=> offset 2 does not land on character boundary (IndexError)
s.bytesplice(3, 4, "x") #=> offset 7 does not land on character boundary (IndexError)

Preliminary discussion:

Discussion:

naruse: I agree to merge it.

Conclusion:

matz: go ahead.

[Feature #18576] Rename `ASCII-8BIT` encoding to `BINARY` (byroot)

The patch is ready.
I'd like to make the change for 3.2.0-preview1, so that we can get early feedback and if it's negative revert before final release.
Matz last statement is ambiguous, does it means OK for 3.2.0-preview1?
There's an open question on wether C API should alias *ascii8bit* functions too.

Preliminary discussion:

(https://github.com/ruby/ruby/pull/5571/files#diff-51920e95310ebfbc1ae31709f3b95f89afffbf4f1a6e38e8b2b406e2fb6197eaR57)

Encoding::ASCII_8BIT was renamed to Encoding::BINARY.

https://github.com/ruby/ruby/pull/5571/files#diff-0b652aaedd3286ea21ba6f6db9f4ec65360d348647c9a2fe4ca457bbe95a9721R44

rb_encdb_declare("BINARY");

Discussion:

ko1: I showed affected gems before meeting, but there may be also applications (not in gems)
matz: application users may not try pre-relese version so it is hard to find out the compatibility issues.
akr: This change doesn't introduce another advantage such as performance improvement, so it can only introduce incompatibility hurts.

Conclusion:

matz: I'll write I'm negative on it.

[Feature #18589] Finer-grained constant invalidation (kddeisz)

We want to trade a very small memory increase for much better constant cache invalidation.
This will allow relying on more stable constant caches for better code specialization in JITs.
This can also help speed up initial boot times since caches are currently invalidated each time a class is created.
Because of APIs like Object#extend, ActiveRecord::Relation#extending, and autoload, constant caches get busted far more often than they should in production applications, and has a measurable impact on request speed.

Preliminary discussion:

ko1: will reply













module M0
  CONST0 = 0
end
module M1
  include M0
  CONST1 = 1
end
class C
  include M1
end

p C::CONST0 #=> 0
p C::CONST1 #=> 1

Conclusion:

matz: accepted. It doesn't change the behavior so we can consider later if it has an issue.

[Feature #18615] Use -Werror=implicit-function-declaration by default for building C extensions (eregon)

OK to do it? It seems an obvious gain and will avoid many confusing errors which happen too late and instead make them clear and early.

Preliminary discussion:

nobu: Currently Ruby uses RTLD_LAZY for dlopen, so Ruby can require an extension library even if some symbol is undefined. It aborts when the undefined symbol is actually used. If this -Werror is enabled, a user will not be able to "gem install".
nobu: Personally, I'd like to enable the option too
mame: I like to enable it by default too, but also I want some workaround to disable it by external environment variable or what not

Discussion:

shyouhei: I don't against about this proposal, but I'm afraid the compatibility.
akr: try it on 3.2? It is 2022.
nobu: now we replace s/Werror/W/ for extensions for -Werror=implicit-function-declaration to show only warning.
mame: can we ask shopify people to try?

Conclusion:

matz: go aheed.
mame: if we have one or more issues, the reports are very welcome.

[Feature #18566] Merge `io-wait` gem into core `IO` class. (byroot)

It's very small and any non-trivial IO code will require it.
Merge io-wait into io.c for Ruby 3.2
Remove io-wait as a dependency of all gems maintained by ruby-core (e.g. net-protocol).
Publish a new io-wait version that is simply an empty gem.
Add a lib/io/wait.rb stub, with eventually a verbose deprecation warning.
It was suggested to do the same with io-nonblock.

Discussion:

nobu: The reason why I created it as an extention library is because it was just possible
shyouhei: Is there any reason to merge it to the core?
mame: I think there is no special reason. It once caused a dependency problem: net-protocol depended on io-wait gem, but older rubies cannot handle it because they have not io-wait "gem" even though it has io-wait extension library.
mame: Now net-protocol does NOT depend on io-wait gem, so there is no problem even if we keep the current status (keep io-wait as a default gem)
ko1: Is there a good reason to keep it as a separate gem/ext?
mame: IMO there is no reason.
nobu: I regret to have introduced some methods like nread a little.
akr: Do we merge all the methods of io-wait gem?
ko1: It would be good if the number of methods being merged is smaller.

/srv/gems/ruby_volt-0.0.5/lib/ruby_volt/connection.rb:        socket.read(socket.nread) if socket_open? && socket.nread > 0 # Flush data waiting to be read
/srv/gems/shopify-cli-2.14.0/vendor/deps/webrick/lib/webrick/server.rb:                            sp.read_nonblock([sp.nread, 8].max, buf, exception: false)
/srv/gems/smart_proxy_dynflow-0.7.0/lib/smart_proxy_dynflow/runner/command.rb:          if @command_out.nread.positive?
/srv/gems/smart_proxy_dynflow-0.7.0/lib/smart_proxy_dynflow/runner/command.rb:            lines = @command_out.read_nonblock(@command_out.nread)
/srv/gems/yahns-1.18.0/test/test_wbuf.rb:    Timeout.timeout(10) { b.read(b.nread) until b.nread == 0 }

ko1: We need to consider each method, instead of the whole methods
matz:
- ok:
  - wait_readable/writable
- unknown:
  - wait
  - ready? == wait_readable(0)
    - naming issue: ready_to_read??
  - wait_priority
    - What is this??? No one knows it
  - nread
    - what use case is it for?
    - naming issue
akr: io/nonblock should not be merged because it is not needed for most of applications.

Conclusion:

matz: let's discuss in different tickets to merge methods respectively (listed above as unkonwn).

[Bug #18620] Not possible to partially curry lambda or proc's `call` method (jeremyevans0)

Should we make changes to allow this to work? It complicates the internals, and the benefits seem minimal.
If we do decide to make this change, I've prepared a patch, but the implementation is suboptimal.

Preliminary discussion:

lambda { |a, b| a + b }.method(:call).curry[1][2]
#=> expected: 3
#=> actual: wrong number of arguments (given: 1, expected 2)

mame: I vote for no change. Proc#curry should work as is
nobu: Agree.

Discussion:

usa: I think it is by design








lambda { |a, b| a + b }.curry[1][2]
#=> 3

lambda { |a, b| a + b }.method(:call).curry[1, 2]
#=> 3

lambda { |a, b| a + b }.method(:call).curry(2)[1][2]
#=> 3

Conclusion:

matz: No change.
matz: it would be good to add a dedicated documentation to Proc#curry, such as "it does not work if the arity is -1"

[Feature #15357] `Proc#parameters` returns incomplete type information (jeremyevans0)

Last discussed at the March 2020 developer meeting, but no decision was made.
I still think it makes sense to consider a lambda keyword argument for Proc#parameters.

Preliminary discussion:

pr = proc{|a,b=2| [a,b] }
pr.call(:a)    # => [:a, 2]  # :a is interpret as the first parameter

pr.parameters                # => [[:opt, :a], [:opt, :b]]
pr.parameters(lambda: true)  # => [[:req, :a], [:opt, :b]]

pr = proc{|a=1,b| [a,b] }
pr.call(:a)    # => [1, :a]  # :a is interpret as the second parameter

pr.parameters                # => [[:opt, :a], [:opt, :b]]
pr.parameters(lambda: true)  # => [[:opt, :a], [:req, :b]]

Discussion:

mame: What is the use case?
- https://github.com/larskanis/eventbox/blob/3bcbc30096c6003e96d41c6496c781dfc90ac36a/lib/eventbox/argument_wrapper.rb#L10-L17
matz: Umm, okay?
ko1: Do we need the same keyword for Method#parameters too?
matz: Only Proc#parameters
matz: The name "lambda" is… okay

Conclusion:

matz: accepted. Will reply

[Feature #18563] Add "graphemes" and "each_grapheme" aliases (znz)

Some languages already use graphemes.

Preliminary discussion:

nobu: I feel rather "grapheme" should be omitted.
nobu: Unicode Consortium doesn't have a good brand-new word?
ko1: each_grapheme makes it seem to me that it breaks down into graphemes from one graheme cluster.
nobu: How about graster?

https://hexdocs.pm/elixir/1.12/String.html

Furthermore, this module also presents the concept of grapheme cluster (from now on referenced as graphemes).

https://www.php.net/manual/en/ref.intl.grapheme.php

Grapheme Functions (grapheme_extract, …)

https://jp.mathworks.com/help/textanalytics/ref/splitgraphemes.html

newStr = splitGraphemes(str) splits the string str into graphemes. A grapheme (also known as grapheme cluster) is the Unicode term for human-perceived characters.

Discussion:

naruse: If it is really a common word, we can use it.
naruse: However, we should check only languages: PHP, Elixir, and Matlab.
naruse: We should wait for other languages, don't we?
matz: I want to wait too
mame: We call a HashTable as "Hash" but some people critize the wording
naruse: A string is conceptually important in Ruby, so we should use strict wording
matz: I don't want the dishonor of wrong wording unless it is really common

Conclusion:

matz: For now, I reject it. Will reply.

[Feature #12655] Accessing the method visibility (jeremyevans0)

This issue discusses many things that have been discussed previously in other issues.
I want to focus on one additional method: Module#undefined_instance_methods
We don't currently offer a way to see which methods are undefined in a module.
Is this worth adding? The use case I know of is it would allow significantly simpler implementation of the looksee gem.

Preliminary discussion:

class C0
  def foo = p :C0
end

class C1 < C0
  undef foo
end

C1.new.bar #=> undefined method `bar' for #<C1:0x0000018f8acd15c0> (NoMethodError)
C1.new.foo #=> undefined method `foo' for #<C1:0x000002c703aa5678> (NoMethodError)
  
C1.undefined_instance_methods #=> [:foo]

With proposed Module#undefined_instance_methods, we can get [:foo] with C1.undefined_instance_methods

ko1: I'm positive. Does it check with superclasses?

Discussion:

$ gem-codesearch 'undef_method\b' | grep '\.rb:' | wc
   8674   39277 1150347

class C0
  def foo = 1
  def bar = 1
end

class C1 < C0
  undef foo
  undef bar
end

class C2 < C1
  def bar = 2
end

C2.undefined_instance_methods        #=> ?? []
    
#=> not supported
C2.undefined_instance_methods(true)  #=> [:foo]
C2.undefined_instance_methods(false) #=> []

matz: No need to check superclass? So the ability to check super classes are not needed.

Conclusion:

matz: accepted. The inherited_too optional parameter is not needed.

[Bug #11063] Special singleton class should return true for singleton_class? test (jeremyevans0)

I don't think it is worth changing the existing behavior.
Can this be rejected?

Preliminary discussion:





nil.singleton_class #=> NilClass
nil.singleton_class.singleton_class? #=> false

true.singleton_class.singleton_class? #=> false
false.singleton_class.singleton_class? #=> false

Conclusion:

matz: I think it is not worth to change. rejected

[Bug #18632] Struct.new wrongly treats a positional Hash as keyword arguments (eregon)

Some C functions incorrectly treat a positional Hash as keyword arguments, e.g. Struct.new and Struct#initialize.
This is inconsistent with the separation of positional and keyword arguments in Ruby 3
Jeremy proposed to audit and fix them

Preliminary discussion:

h = { keyword_init: true }
Struct.new(:a, h)
# actual:   it works
# expected: {:keyword_init=>true} is not a symbol (TypeError)

nobu: I think we should fix this particular case

h = { cause: RuntimeError.new("bar") }
raise 'foo', h
#=> Now it works with the following error
#   foo (RuntimeError)
#   bar (RuntimeError)
#
#=> after fixed, it is handled as "raise: (Exception, String)":
#   exception class/object expected (TypeError)

mame: I'm basically positive for the change. If we find a big incompatibility, we can reconsider

Discussion:

nobu: as long as I investigated, only the two methods (Struct.new and Kernel#raise) have the problem

Conclusion:

matz: Please fix them. I want to give it a try. No deprecation seems to be needed to me

[Bug #18625] ruby2_keywords does not unmark the hash if the receiving method has a *rest parameter (eregon)

This seems a clear inconsistency, and it hurts for 3 reasons:
Can cause issues when migrating to other forms of delegation
Makes the ruby2_keywords semantics confusing/inconsistent/more complex
May force other Ruby implementations to replicate this bug if not fixed
I believe we should fix it now. Fixing it later would cause issues when migrating to (*args, **kwargs) or (...).

Preliminary discussion:

# A hash that has "ruby2_keywords" flag
marked_hash = Hash.ruby2_keywords_hash({ a: 1 })
args = [marked_hash]

def single(arg)
  arg
end

def splat(*args)
  args.last
end

after_usage = single(*args)
p Hash.ruby2_keywords_hash?(after_usage) #=> false

after_usage = splat(*args)
p Hash.ruby2_keywords_hash?(after_usage) #=> true

def target(a:)
  p a
end

# after the patch, ruby2_keywords modifier is requried to bar
def bar(*args)
  target(*args)
end

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

p foo(a: 42) #=> 42 in Ruby 3.1
             #=> ArgumentError after the patch

Conclusion:

matz: I think it is good to fix
mame: It may break (a lot of?) existing programs, but hopefully easy to fix. I'll discuss

[Bug #18633] `proc { |a, **kw| a }` autosplats and treats empty kwargs specially (eregon)

Intended or bug? Should we fix it?

Preliminary discussion:





proc {|a| a }.call([1, 2])         #=> [1, 2]
proc {|a, **kw| a }.call([1, 2])   #=> 1  # should be [1, 2]
proc {|a, kw: 42| a }.call([1, 2]) #=> 1  # should be [1, 2]

proc {|a,| a }.call([1, 2])        #=> 1


proc {|a, **kw| a }.call([1, 2])       #=> 1  # should be [1, 2]
proc {|a, **kw| a }.call([1, 2], **{}) #=> [1, 2]

FYI: Jeremy has fixed this for #16166


proc {|*a, **kw| a }.call([1, 2])  #=> old: [1, 2], new: [[1, 2]]

Conclusion:

matz: I think it should be fixed

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DevMeeting-2022-03-17

DateTime and location

Next Date

Announce

About release timeframe

Check security tickets

Ordinary tickets

[Feature #18598] Add String#bytesplice (shugo)

[Feature #18576] Rename ASCII-8BIT encoding to BINARY (byroot)

[Feature #18589] Finer-grained constant invalidation (kddeisz)

[Feature #18615] Use -Werror=implicit-function-declaration by default for building C extensions (eregon)

[Feature #18566] Merge io-wait gem into core IO class. (byroot)

[Bug #18620] Not possible to partially curry lambda or proc's call method (jeremyevans0)

[Feature #15357] Proc#parameters returns incomplete type information (jeremyevans0)

[Feature #18563] Add "graphemes" and "each_grapheme" aliases (znz)

[Feature #12655] Accessing the method visibility (jeremyevans0)

[Bug #11063] Special singleton class should return true for singleton_class? test (jeremyevans0)

[Bug #18632] Struct.new wrongly treats a positional Hash as keyword arguments (eregon)

[Bug #18625] ruby2_keywords does not unmark the hash if the receiving method has a *rest parameter (eregon)

[Bug #18633] proc { |a, **kw| a } autosplats and treats empty kwargs specially (eregon)

[Feature #18576] Rename `ASCII-8BIT` encoding to `BINARY` (byroot)

[Feature #18566] Merge `io-wait` gem into core `IO` class. (byroot)

[Bug #18620] Not possible to partially curry lambda or proc's `call` method (jeremyevans0)

[Feature #15357] `Proc#parameters` returns incomplete type information (jeremyevans0)

[Bug #18633] `proc { |a, **kw| a }` autosplats and treats empty kwargs specially (eregon)