[ruby-core:109921] [Ruby master Bug#19003] TracePoint behavior inconsistency in 3.2.0-preview2
From:
"jeremyevans0 (Jeremy Evans)" <noreply@...>
Date:
2022-09-16 17:58:34 UTC
List:
ruby-core #109921
Issue #19003 has been updated by jeremyevans0 (Jeremy Evans).
This issue shows a case where you are adding a local tracepoint during global tracepoint processing. There are a couple approaches Ruby could take here:
1) For a local tracepoint added during global tracepoint processing, only call it for future events and not the current event. This appears to be the Ruby 3.1 behavior.
2) For a local tracepoint added during global tracepoint processing, call it for future events and the current event. This appears to be the Ruby 3.2 behavior.
In both cases, a local tracepoint added during local tracepoint processing (the recursive call inside `step_over`) is not called for the current event. If it was, the code example would result in an infinite loop.
Can you explain why you think this behavior change is a bug? Does Ruby specify that local tracepoints added during global tracepoint processing for an event should not apply to the current event, and only future events?
----------------------------------------
Bug #19003: TracePoint behavior inconsistency in 3.2.0-preview2
https://bugs.ruby-lang.org/issues/19003#change-99169
* Author: hurricup (Alexandr Evstigneev)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.2.0preview2 (2022-09-09 master 35cfc9a3bb) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
This is kind of continuation of my previous report about global/local TP processing (#18730).
Sample script:
```rb
def foo
return 1
end
puts RubyVM::InstructionSequence.of(method :foo).disasm
def step_over
TracePoint.new(:line, :return, :b_return) do |tp|
puts "Step over hits by #{tp.event} at #{tp.lineno}"
step_over
tp.disable
end.enable(target: RubyVM::InstructionSequence.of(method :foo), target_thread: Thread.current)
end
TracePoint.new(:line, :return, :b_return) do |tp|
if tp.lineno == 2
puts "Step into hits by #{tp.event} at #{tp.lineno}"
step_over
tp.disable
end
end.enable(target_thread: Thread.current)
a = foo
```
In ruby 3.1.2 we have expected behavior. Output:
```
== disasm: #<ISeq:foo@/home/hurricup/Projects/ruby-debugger/jb-debase-30/test_sample.rb:1 (1,0)-(3,3)> (catch: FALSE)
0000 putobject_INT2FIX_1_ ( 2)[LiCa]
0001 leave ( 3)[Re]
Step into hits by line at 2
Step over hits by return at 3
```
In ruby 3.2.0-preview2 - not so much. Output:
```
== disasm: #<ISeq:foo@/home/hurricup/Projects/ruby-debugger/jb-debase-30/test_sample.rb:1 (1,0)-(3,3)> (catch: false)
0000 putobject_INT2FIX_1_ ( 2)[LiCa]
0001 leave ( 3)[Re]
Step into hits by line at 2
Step over hits by line at 2
Step over hits by return at 3
```
--
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