Bug #12091: Freezing a SortedSet breaks Enumerable

• Status: Closed
• Assignee: knu (Akinori MUSHA)
• Target version: -
• ruby -v: ruby 2.4.0dev (2016-02-20 trunk 53876) [x86_64-darwin15]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN

[drewish (Andrew Morton)]

If you freeze a SortedSet it looses most functionality because of the way to_a is implemented:

irb(main):001:0> require 'set'
=> true
irb(main):002:0> Set.new.freeze
=> #<Set: {}>
irb(main):003:0> SortedSet.new.freeze
RuntimeError: can't modify frozen SortedSet
	from /Users/andrew/.rbenv/versions/2.3.0-dev/lib/ruby/2.4.0/set.rb:679:in `to_a'
	from /Users/andrew/.rbenv/versions/2.3.0-dev/lib/ruby/2.4.0/set.rb:541:in `inspect'
	from /Users/andrew/.rbenv/versions/2.3.0-dev/bin/irb:11:in `<main>'

And since each method relies on to_a, all the Enumerable methods are also broken:

irb(main):006:0> SortedSet.new([1, 2, 2]).freeze.max
RuntimeError: can't modify frozen SortedSet
	from /Users/andrew/.rbenv/versions/2.3.0-dev/lib/ruby/2.4.0/set.rb:679:in `to_a'
	from /Users/andrew/.rbenv/versions/2.3.0-dev/lib/ruby/2.4.0/set.rb:674:in `each'
	from (irb):6:in `max'
	from (irb):6
	from /Users/andrew/.rbenv/versions/2.3.0-dev/bin/irb:11:in `<main>'

The relevant code is:

          def to_a
            (@keys = @hash.keys).sort! unless @keys
            @keys
          end

[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned
• Assignee set to knu (Akinori MUSHA)

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[knu (Akinori MUSHA)]

• Status changed from Assigned to Closed

Applied in changeset trunk|r60298.

---

Allow a SortedSet to be frozen and still functional [Bug #12091]

[knu (Akinori MUSHA)]

Fixed, thanks!