Bug #10685: Segfault from keyword rest arg when coercing an object that defines to_hash

• Status: Closed
• Assignee: -
• Target version: 2.2.0
• ruby -v: 2.2.0p0
• Backport: 2.0.0: DONTNEED, 2.1: DONTNEED, 2.2: DONE

[headius (Charles Nutter)]

This spec appears to cause the segfault mentioned in http://rubini.us/2014/12/31/matz-s-ruby-developers-don-t-use-rubyspec/ today.

    it "calls #to_hash on the last element if keyword arguments are present" do
      obj = mock("destructure block keyword arguments")
      obj.should_receive(:to_hash).and_return({x: 9})

      result = m([1, 2, 3, obj]) { |a, *b, c, **k| [a, b, c, k] }
      result.should == [1, [2], 3, {x: 9}]
    end

I tried to boil it down to a shorter example and was not able to isolate it from RubySpec/mspec entanglement.

Here's the full dump including the last spec line that starts to run (the spec above): https://gist.github.com/headius/5d52df923eb615729ca3

I ran it using mspec gem from rubyspec's "archive" branch using "mspec ci -f s language".

[chrisseaton (Chris Seaton)]

I think this is the equivalent code extracted from MSpec. But I can't get this to crash on 2.2.0p0.

def m(a) yield a end

class Mock
  def to_hash
    puts 'to_hash called'
    {x: 9}
  end
end

obj = Mock.new

result = m([1, 2, 3, obj]) { |a, *b, c, **k| [a, b, c, k] }
p result#.should == [1, [2], 3, {x: 9}]
p result == [1, [2], 3, {x: 9}]

[normalperson (Eric Wong)]

Thanks for the report, looks like nobu committed a fix as r49088

This spec appears to cause the segfault mentioned in
http://rubini.us/2014/12/31/matz-s-ruby-developers-don-t-use-rubyspec/
today.

Fwiw, I do run "make test-rubyspec" before I commit,
but that's naruse's repo which I guess is different..

Like many projects nowadays, I won't bother contributing to rubyspec
because it requires an account on a proprietary service provider.
Free Software (e.g. Ruby) needs Free tools:
http://mako.cc/writing/hill-free_tools.html

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

Applied in changeset r49089.

---

vm_args.c: add ref r49088

• vm_args.c (keyword_hash_p): fix non-symbol keys hash.
  rb_extract_keywords() returns 0 not Qnil when no symbol keys is
  included. [ruby-core:67264] [Bug #10685]

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN to 2.0.0: DONTNEED, 2.1: DONTNEED, 2.2: REQUIRED

[nobu (Nobuyoshi Nakada)]

Chris Seaton wrote:

I think this is the equivalent code extracted from MSpec. But I can't get this to crash on 2.2.0p0.

It's another failure, but false positive.

[nobu (Nobuyoshi Nakada)]

• Has duplicate Bug #10695: Segmentation fault with *args and **kwargs added

[ktsj (Kazuki Tsujimoto)]

• Has duplicate Bug #10734: Segfault when combining default arguments with keyword arguments added

[naruse (Yui NARUSE)]

• Backport changed from 2.0.0: DONTNEED, 2.1: DONTNEED, 2.2: REQUIRED to 2.0.0: DONTNEED, 2.1: DONTNEED, 2.2: DONE

ruby_2_2 r49272 merged revision(s) 49089.