Bug #20218: aset/masgn/op_asgn with keyword arguments - Ruby master - Ruby Issue Tracking System

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Bug #20218

closed

aset/masgn/op_asgn with keyword arguments

Added by jeremyevans0 (Jeremy Evans) 3 months ago. Updated about 2 months ago.

Status:

Closed

Assignee:

Target version:

ruby -v:

Backport:

3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[ruby-core:116460]

Description

I found that use of keyword arguments in multiple assignment is broken in 3.3 and master:

h = {a: 1}
o = []
def o.[]=(*args, **kw)
  replace([args, kw])
end

# This segfaults as RHS argument is not a hash
o[1, a: 1], _ = [1, 2]


# This passes the RHS argument as keywords to the method, treating keyword splat as positional argument
o[1, **h], _ = [{b: 3}, 2]
o
# => [[1, {:a=>1}], {:b=>3}]

Before 3.3, keyword arguments were treated as positional arguments.

This is similar to #19918, but for keyword arguments instead of block arguments.

@matz (Yukihiro Matsumoto) indicated he wanted to prohibit block arguments in aset/masgn and presumably also op_asgn (making them SyntaxErrors). Can we also prohibit keyword arguments in aset/masgn/op_asgn?

Note that aset treats keyword arguments as regular arguments:

o[1, a: 1] = 2
o
# => [[1, {:a=>1}, 2], {}]

o[1, **h] = {b: 3}
o
# => [[1, {:a=>2}, {:b=>3}], {}]

While op_asgn treats keyword arguments as keywords:

h = {a: 2}
o = []
def o.[](*args, **kw)
  concat([:[], args, kw])
  x = Object.new
  def x.+(v)
    [:x, v]
  end
  x
end
def o.[]=(*args, **kw)
  concat([:[]=, args, kw])
end
o[1, a: 1] += 2
o
# => [:[], [1], {:a=>1}, :[]=, [1, [:x, 2]], {:a=>1}]

o.clear
o[1, **h] += {b: 3}
o
# => [:[], [1], {:a=>2}, :[]=, [1, [:x, {:b=>3}]], {:a=>2}]