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Bug #15911

Updated by cfis (Charlie Savage) almost 5 years ago

While updating ruby-prof, I ran into an issue while profiling rails that caused ruby-prof to show an incorrect method invocation tree. This caused by the use of the ||= operator in minitest. 

 Here is a small test case: 

 ``` <pre> 
 class Operators 
   def self.should_be_called_by_test 
   end 

   def self.test 
     self.a 
     should_be_called_by_test 
   end 

   def self.b=(value) 
   end 

   def self.b 
   end 

   def self.a 
     self.b ||= :random 
   end 
 end 

 tp = TracePoint.new(:call, :c_call, :return, :c_return) do |event| 
   p [event.event, event.method_id] 
 end 

 tp.enable do 
   Operators.test 
 end 
 ``` </pre> 

 This is the result: 

 ``` <pre> 
 [:call, :test] 
 [:call, :a] 
 [:call, :b] 
 [:return, :b] 
 [:call, :b=] 
 [:return, :b=] 
                                     <---------- Missing [:return, :a] 
 [:call, :should_be_called_by_test] 
 [:return, :should_be_called_by_test] 
 [:return, :test] 
 </pre> 

 ``` 
 Notice there is a missing :return event for the :a method. 

 ruby -v 
 ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin18]

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