[ruby-core:67721] [ruby-trunk - Bug #10764] [Open] TracePoint API reports events for the last last line of multiline ||=

Issue #10764 has been reported by Oleg Sukhodolsky.

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Bug #10764: TracePoint API reports events for the last last line of multiline ||=
https://bugs.ruby-lang.org/issues/10764

* Author: Oleg Sukhodolsky
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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Here is a simple test which demonstrates the problem:

~~~ruby
TracePoint.new do |tp|
  printf "%8s %s:%-2d %13s\n", tp.event, tp.path, tp.lineno, tp.method_id
end.enable

def foo
end

def bar
  @foo ||= foo do
  end

  @foo &&= foo do
  end

  @foo = foo do
  end
end

bar
~~~

Here is test's output I've got with 2.2.0

~~~ruby
c_return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:3         enable
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:5               
  c_call /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:5   method_added
c_return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:5   method_added
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:8               
  c_call /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:8   method_added
c_return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:8   method_added
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:19              
    call /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:8            bar
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:10           bar
    call /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:5            foo
  return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:6            foo
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:13           bar
    line /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:15           bar
    call /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:5            foo
  return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:6            foo
  return /Users/user/work/tests/slim-tests/ruby/debugger/ruby-16152.rb:17           bar
c_return -e:1           load
~~~
As you can see from the output we do get events for last line for ||= and &&= but for the first line for = (looks a little bit inconsistent for me ;)
We do use the API to implement debugger (https://github.com/denofevil/debase and https://github.com/ruby-debug/ruby-debug-ide) and such behavior means
that either user has be be very smart about setting breakpoints (it needs to know/guess at which lines it is possible to set breakpoints and this is not very obvious)
or debugger should be even smarter than the user and move breakpoints to the closest allowed place (which is even harder).

It would be nice to have consistent behavior and get events for the first line of the a multi line assignment in all cases.

Originally the problem reported agains RubyMine's debugger (https://youtrack.jetbrains.com/issue/RUBY-16152)




-- 
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