Bug #21338: TracePoint Not Triggered for Kernel#block_given?

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 3.4.2 (2025-02-15 revision d2930f8e7a) +PRISM [x86_64-linux]
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[cfis (Charlie Savage)]

When updating ruby-prof for Ruby 3.4, various tests now fail because a method enter/leave tracepoint is not triggered for Kernel#block_given? For example:

https://github.com/ruby-prof/ruby-prof/blob/master/test/line_number_test.rb#L184

In 3.3 a tracepoint was triggered but not in earlier Ruby versions.

[alanwu (Alan Wu)]

• Status changed from Open to Rejected

It's a C method in 3.4, so you can listen for :c_call:

ruby -ve 'TracePoint.new(:c_call) { p _1 }.enable { block_given? }'

Wether something is a C or Ruby method is not something we guarantee to be stable, though, so it's not a bug now that a different event fires.

[cfis (Charlie Savage)]

ruby-prof does listen for C calls. See:

https://github.com/ruby-prof/ruby-prof/blob/master/ext/ruby_prof/rp_profile.c#L337

void prof_install_hook(VALUE self)
{
    prof_profile_t* profile = prof_get_profile(self);

    VALUE event_tracepoint = rb_tracepoint_new(Qnil,
                                               RUBY_EVENT_CALL | RUBY_EVENT_RETURN |
                                               RUBY_EVENT_C_CALL | RUBY_EVENT_C_RETURN |
                                               RUBY_EVENT_LINE,
                                               prof_event_hook, profile);

Once again, this is change in behavior between 3.3 and 3.4. Was it intentional?