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Bug #9358

TracePoint's raise event should throw 'not supported by this event (RuntimeError)' on calling return_value

Added by andhapp (Anuj Dutta) over 6 years ago. Updated 11 months ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Target version:
-
ruby -v:
2.1.0
Backport:
[ruby-core:59521]

Description

=begin
Hello,

In TracePoint class, if a particular introspection method is not supported then 'not supported by this event (RuntimeError)' is thrown.

=== Line event doesn't support raised_exception

 TracePoint.trace(:line) do |tp|
   p tp.raised_exception
 end

 #=> RuntimeError: 'raised_exception' not supported by this event

However, that doesn't seem to happen for 'raise' event. The call to return_value stops the trace altogether. Here's the code to reproduce it:

=== Code

class Car
def self.start
begin
raise StandardError.new, 'Error!'
rescue
end
end
end

TracePoint.trace(:raise) do |tp|
p tp.raised_exception
p [tp.return_value, tp.raised_exception]
end

Car.start

=== Expected Output
#=> #
#=> `return_value': not supported by this event (RuntimeError)

=== Actual Output
#=> #

Is this expected behaviour?

Thanks

=end

Updated by jeremyevans0 (Jeremy Evans) 11 months ago

  • Backport deleted (1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN)
  • Status changed from Open to Closed

This is expected behavior. As the documentation states:

raised_exception: Value from exception raised on the :raise event
return_value: Return value from :return, c_return, and b_return event

You cannot call methods not supported by the type. You can use the event method to check the type of the particular event.

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