Add support for comparing objects that are later deleted.

 






 

 


  Review Request #14332
  —
  Created Feb. 6, 2025 and updated 

 




















 

  

   Information

  





 
 

  chipx86
 









 
 

  django-assert-queries
 









 
 

  main
 









 
 

  
 









 
 

  
 






 




 

  

   Reviewers

  





 
 

  beanbag-misc
 









 
 

  
 






 








 





  


 
 

  
When deleting an object via any relation (including when cascading

certain types of relations), we can end up in a situation where objects

can no longer be compared.


Model object comparisons check the primary key and model type. If one of

the primary keys is null, the model falls back to checking if the two

objects are the same exact instances.


What happens with deletion is that Django will perform a query

internally during delete object collection, delete them, and erase the

primary keys. This leads to several queries that are captured that

reference an object that no longer has a primary key and won't be the

same instances the unit test would have.


The solution to this is to listen in on object deletion and record any

primary keys being deleted. Then, during Q normalization, we can wrap

every model object referenced in a query to improve its equality checks,

factoring in instances that are deleted. This allows us to compare

instances.

 








  


 
 

  
All unit tests pass.


Tested this with unit tests in Review Board that were breaking due to

the deletion comparison behavior in Django.

 







 









 





  

 


 
 

  



 

  
   


    Summary
    ID

   

  
  

   


    

     

      Add support for comparing objects that are later deleted.
      
When deleting an object via any relation (including when cascading
certain types of relations), we can end up in a situation where objects
can no longer be compared.

Model object comparisons check the primary key and model type. If one of
the primary keys is null, the model falls back to checking if the two
objects are the same exact instances.

What happens with deletion is that Django will perform a query
internally during delete object collection, delete them, and erase the
primary keys. This leads to several queries that are captured that
reference an object that no longer has a primary key and won't be the
same instances the unit test would have.

The solution to this is to listen in on object deletion and record any
primary keys being deleted. Then, during `Q` normalization, we can wrap
every model object referenced in a query to improve its equality checks,
factoring in instances that are deleted. This allows us to compare
instances.

     


    		
    0df2ffa268ab14052910ebcd7a1b17cfa64ed47b

   



  
 




 













 






 
 
 

  

   

    

     
    

    
    
     
  • 
      
     
    • 
     
  • 
      
     
    • 
     
  • 
      
     
    • 
     
  • 
      
     
    • 
     
  • 
      
     
    • 
    

   

   

    
     

      Description
      From
      Last Updated
     

    
    



     

      
       
       
'django.db.models.expressions.NegatedExpression' imported but unused Column: 1 Error code: F401

      		
      
       reviewbotreviewbot
      
      
       
      
     


    
   

  

 







 






  

 



















 




 

  


   

   

    
 
Checks run (1 failed, 1 succeeded)


    
   


  

  

  





 

 flake8
 failed.
 





 

 JSHint
 passed.
 













 
flake8

 


 










  

 





 














 



 

  

   




chipx86




   

   

  

 



 















 



 

  

   




chipx86




   

   

  

 



 

  


   

   

    
 Review request changed

    
   


  

  

  









  

   

    Change Summary:
   

   

    
    

  • Removed an unused import.
    • 

  • Updated the version to 2.0.
    • 


   

  








  

   

    Commits:
   

   

    





 

  
   


    

    Summary
    ID

   

  
  

   


    

    

     

      Add support for comparing objects that are later deleted.
      
When deleting an object via any relation (including when cascading
certain types of relations), we can end up in a situation where objects
can no longer be compared.

Model object comparisons check the primary key and model type. If one of
the primary keys is null, the model falls back to checking if the two
objects are the same exact instances.

What happens with deletion is that Django will perform a query
internally during delete object collection, delete them, and erase the
primary keys. This leads to several queries that are captured that
reference an object that no longer has a primary key and won't be the
same instances the unit test would have.

The solution to this is to listen in on object deletion and record any
primary keys being deleted. Then, during `Q` normalization, we can wrap
every model object referenced in a query to improve its equality checks,
factoring in instances that are deleted. This allows us to compare
instances.

     


    		
    4a3bb58db38e9f6026b909d1108599e211cb164a

   




   


    

    

     

      Add support for comparing objects that are later deleted.
      
When deleting an object via any relation (including when cascading
certain types of relations), we can end up in a situation where objects
can no longer be compared.

Model object comparisons check the primary key and model type. If one of
the primary keys is null, the model falls back to checking if the two
objects are the same exact instances.

What happens with deletion is that Django will perform a query
internally during delete object collection, delete them, and erase the
primary keys. This leads to several queries that are captured that
reference an object that no longer has a primary key and won't be the
same instances the unit test would have.

The solution to this is to listen in on object deletion and record any
primary keys being deleted. Then, during `Q` normalization, we can wrap
every model object referenced in a query to improve its equality checks,
factoring in instances that are deleted. This allows us to compare
instances.

     


    		
    0df2ffa268ab14052910ebcd7a1b17cfa64ed47b

   



  
 







   

  





  

   

    Diff:
   

   

    
 Revision 2 (+652 -24)
Show changes
 
    django_assert_queries/query_catcher.py 
    django_assert_queries/query_comparator.py 
    django_assert_queries/tests/test_query_catcher.py 
    django_assert_queries/tests/test_query_comparator.py 
 

   

  











 

  
Checks run (2 succeeded)



  

 flake8
 passed.
 





  

 JSHint
 passed.
 





 















  

 
















 





 

  

   




david




   

   







  

 



 

  


   

   

    
 
david



    
   


  

  

  



    




  1. 
 
    
  
    
   
    Ship It!
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

    2. 















  2. 
 
    
  
    
   
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

    3.