end-less methods cause hangs

[cromega]

Subject of the issue

Ruby 3's end-less methods seem to make Rspec hang when a method raises an error.

Your environment

• Ruby version: 3.0.1
• rspec-core version: 3.10.1

Steps to reproduce

require 'rspec/autorun'

class Test
  def foo = (raise 'error')
  def bar = 123
end

RSpec.describe Test do
  describe '#foo' do
    it 'returns' do
      expect(Test.new.foo).to eq true
    end
  end
end

bundle exec ruby test.rb

Test
  #foo
    returns (FAILED - 1)

[hangs]

Expected behavior

This test run should produce a failure with stacktrace and error details as the example doesn't expect the error.

Actual behavior

RSpec hangs indefinitely.

Commenting out the bar method, moving it above foo or turning it into a method with the classic syntax sorts the problem.

[pirj]

Interesting, thanks for reporting.
I suspect the problem is somewhere in https://github.com/rspec/rspec-support/tree/main/lib/rspec/support/source/
Would you like to hack on this given all the support and guidance necessary?

[cromega]

Thanks for the pointers, I will give it a stab.

[cromega]

I added a test case to the snipper_extractor tests which will come in handy verifying the fix later.

I don't see a simple fix however. The assumption that a token can tell whether it's an opening token does not hold anymore.

def foo = 123

def bar =
123

are both valid methods. The solution involves changing the logic for figuring out how much code to add around an error. Most likely changes will need to be made both to the snippet extractor and rely on nodes instead of tokens probably.

[pirj]

You're right.
I'm not sure behind the reasoning for the solution to use source tokens. Maybe Ripper didn't provide line numbers back then?

Wondering if line_range_of_expression can be simplified to use the information that expression_node.sexp already has.
For

2   def foo = (raise 'error')

expression.sexp is:

=> [:def,
 [:@ident, "foo", [2, 6]],
 nil,
 [:paren,
  [[:command,
    [:@ident, "raise", [2, 13]],
    [:args_add_block,
     [[:string_literal, [:string_content, [:@tstring_content, "error", [2, 20]]]]],
     false]]]]]

For:

2  def foo =
3    (raise 'err' \
4     'or')

it's

=> [:command,
 [:@ident, "raise", [3, 5]],
 [:args_add_block,
  [[:string_concat,
    [:string_literal, [:string_content, [:@tstring_content, "err", [3, 12]]]],
    [:string_literal, [:string_content, [:@tstring_content, "or", [4, 6]]]]]],
  false]]

line_range_of_expression should return 3..4, and it's visible in sexp. I only experience with parser gem, and can't advise on what's the best way to extract line numbers from Ripper's sexp.

[JonRowe]

@yujinakayama can you provide an insight as to why the original was built the way it is? Or any hints on how to fix this?

[yujinakayama]

I'll take a look.

can you provide an insight as to why the original was built the way it is?

As far as I remember I made SnippetExtractor to utilize tokens to detect expression lines correctly (like this) since such information is not included in AST.