Bug #18646: Inconsistent behavior for the targeted TracePoints in ruby 2.6-2.7 and 3+

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN

[hurricup (Alexandr Evstigneev)]

Ruby 2.6 introduced the API for targeted tracepoints.
But for some reason, before ruby 3.0, tracepoints looks exclusive per iseq.

Consider an example:

def somemethod
  puts 1
  puts 2
  puts 3
end

tp1 = TracePoint.new(:line) { |tp| puts 'This is tp1'}
tp2 = TracePoint.new(:line) { |tp| puts 'This is tp2'}

method_iseq = RubyVM::InstructionSequence.of(method :somemethod)
tp1.enable(target: method_iseq, target_line: 2)
tp2.enable(target: method_iseq, target_line: 4)
somemethod

Ruby 2.6-2.7 prints :

1
2
This is tp2
3

And this is unexpected, because we have 2 tracepoints and expecting both to work. But actually, only last enabled does.

Ruby 3+ work as expected:

This is tp1
1
2
This is tp2
3

Would be really nice to have consistent 3+ behavior everywhere

[hurricup (Alexandr Evstigneev)]

Looks like this was fixed in https://bugs.ruby-lang.org/issues/17302
Any plans to backport to 2.6/2.7?

[Eregon (Benoit Daloze)]

• Related to Bug #17302: The TracePoint API does not allow setting multiple line traces within the same method (ISEQ) added

[Eregon (Benoit Daloze)]

• Status changed from Open to Closed

I've set the backport field for https://bugs.ruby-lang.org/issues/17302.
For 2.6 it's unlikely given it's soon EOL.
In any case it's up to branch maintainers.

I'll close this since everything is tracked by the backport field now.