From: "byroot (Jean Boussier)" <noreply@...>
Date: 2021-11-26T16:46:57+00:00
Subject: [ruby-core:106292] [Ruby master Bug#18250] Anonymous variables seem to break `Ractor.make_shareable`

Issue #18250 has been updated by byroot (Jean Boussier).


I tried to backport these 5 commits and it does solve the problem in normal builds. However with `cppflags=-DRUBY_DEBUG` I do get the following error:

```
estISeq#test_cdhash_after_roundtripWe are killing the stack canary set by opt_case_dispatch, at <RubyVM::InstructionSequence:<compiled>@/Users/byroot/src/github.com/Shopify/ruby/test/ruby/test_iseq.rb:1>@pc=25
watch out the C stack trace.
== disasm: #<ISeq:<compiled>@/Users/byroot/src/github.com/Shopify/ruby/test/ruby/test_iseq.rb:1 (1,0)-(4,3)> (catch: FALSE)
0000 opt_getinlinecache                     9, <is:0>                 (   1)[Li]
0003 putobject                              true
0005 getconstant                            :Class
0007 opt_setinlinecache                     <is:0>
0009 opt_getinlinecache                     18, <is:1>
0012 putobject                              true
0014 getconstant                            :String
0016 opt_setinlinecache                     <is:1>
0018 opt_send_without_block                 <calldata!mid:new, argc:1, ARGS_SIMPLE>
0020 putstring                              "foo"
0022 opt_send_without_block                 <calldata!mid:new, argc:1, ARGS_SIMPLE>
0024 dup
0025 opt_case_dispatch                      <cdhash>, 35
0028 dup                                                              (   2)
0029 putobject                              "foo"
0031 checkmatch                             2
0033 branchif                               38
0035 pop                                                              (   1)
0036 putnil
0037 leave                                                            (   3)
0038 pop                                                              (   2)
0039 putobject                              42                        (   3)[Li]
0041 leave
/Users/byroot/src/github.com/Shopify/ruby/test/ruby/test_iseq.rb:1: [BUG] see above.
```

From this test:

```ruby
  def test_cdhash_after_roundtrip
    # CDHASH was not built properly when loading from binary and
    # was causing opt_case_dispatch to clobber its stack canary
    # for its "leaf" instruction attribute.
    iseq = compile(<<~EOF)
      case Class.new(String).new("foo")
      when "foo"
        42
      end
    EOF
    assert_equal(42, ISeq.load_from_binary(iseq.to_binary).eval)
  end
```

That test was added in 4323fa96c4350ecad5f3d607805b7ecd3870bdb5, so I wonder if we miss something.

----------------------------------------
Bug #18250: Anonymous variables seem to break `Ractor.make_shareable`
https://bugs.ruby-lang.org/issues/18250#change-94917

* Author: tenderlovemaking (Aaron Patterson)
* Status: Closed
* Priority: Normal
* ruby -v: ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-darwin20]
* Backport: 2.7: DONTNEED, 3.0: REQUIRED
----------------------------------------
The following code breaks with a strange error:

```ruby
def foo(*); ->{ super };end
Ractor.make_shareable(foo) # expected Symbol
```

Output:

```
[aaron@tc ~/g/ruby (master)]$ cat test.rb
def foo(*); ->{ super };end      
Ractor.make_shareable(foo) # expected Symbol
[aaron@tc ~/g/ruby (master)]$ ruby test.rb
<internal:ractor>:816:in `make_shareable': wrong argument type false (expected Symbol) (TypeError)
        from test.rb:2:in `<main>'
[aaron@tc ~/g/ruby (master)]$
```

The reason is because the `*` parameter has no name, but Ractor tries to find the name so it can make an exception.

I *expect* the above program to raise an `Ractor::IsolationError`, but instead it raises a `TypeError`.

I've attached a patch that fixes this bug.

---Files--------------------------------
0001-Give-params-a-name.patch (3.33 KB)


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