Call to ErrorHighlight::spot returns partial data for some exceptions

[sdcorey]

Configuration

ruby 3.3.3

Steps to Reproduce

Run the following script error_script.rb:

begin
  x = nil
  x += 5
rescue StandardError => exception
  pp ErrorHighlight.spot(exception, backtrace_location: exception.backtrace_locations[0])
end

using

ruby error_script.rb

Expected Results

My reading of the comment in the header above the ErrorHighlight::spot method is that if its return value is not nil, it should be a hash containing, among other things, integer values corresponding to the :first_lineno and :last_lineno keys.

Actual Results

ErrorHighlight::spot returns a hash in which the values corresponding to the :first_lineno and :last_lineno keys are nil.

Analysis

The above program eventually finds itself in the last elsif clause of ErrorHighlight::Spotter#spot_call_for_name. That clause doesn't set the @beg_lineno and @end_lineno instance variables, whereas all the other clauses in that statement do. Eventually these variable values find their way into the return value of ErrorHighlight::Spotter#spot as nils.

I noticed it because it causes rails exception reporting code to malfunction in certain circumstances. #54384

[mame]

Indeed, sorry! I think #59 will fix the issue.

[sdcorey]

Thanks for your quick work.