Support post_mortem mode via entering specific frames #1103

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1. fabioz commented on Oct 27, 2022

   

   Fabio Zadrozny (fabioz)

   on Oct 27, 2022

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   Closing this as this is a duplicate of: #723 (note that there's some code on that issue on how to do that with the current version of the debugger -- it uses some internal APIs, and we'd like to have better public APIs for this, but that can probably be used in the meanwhile... that code has been stable for quite a while and there are no plans to change it).
2. Fabio Zadrozny (fabioz)

   closed this as completedon Oct 27, 2022
3. wookayin commented on Oct 27, 2022

   

   Jongwook Choi (wookayin)

   on Oct 27, 2022

   Last edited by wookayin

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   Thanks for the pointer to #723 (comment) --- which I didn't find while searching the issues with the keywords I was using!

   Based on the code example you provided and a single function extracted from that (#723 (comment)), I was able to make the debugger enter and stop at the exception raised out of a pytest method.

   Below is a proof-of-concept, but a single-file script to demonstrate the behavior:

   """A script to run pytest tests with debugger stopping at exceptions."""
   
   from typing import Union
   
   import pytest
   
   
   def test_foo():
     x = "some local variable"
     with pytest.raises(ValueError):
       raise ValueError("The debugger should not stop here")
     assert False, "A debugger should stop here"
   
   
   def test_bar():
     assert False, "A debugger should stop here AS WELL"
   
   
   def maybe_debugpy_postmortem(excinfo):
     """Make the debugpy debugger enter and stop at a raised exception.
   
     excinfo: A (type(e), e, e.__traceback__) tuple. See sys.exc_info()
     """
     import debugpy
     if not debugpy.is_client_connected():
       return  # Do not thing if not running with a DAP debugger
   
     import threading
     import pydevd
   
     py_db = pydevd.get_global_debugger()
     thread = threading.current_thread()
     additional_info = py_db.set_additional_thread_info(thread)
     additional_info.is_tracing += 1
     try:
       py_db.stop_on_unhandled_exception(py_db, thread, additional_info, excinfo)
     finally:
       additional_info.is_tracing -= 1
   
   
   class PytestDebuggerIntegration:
   
     @staticmethod
     def pytest_exception_interact(
         node: Union['pytest.Item', 'pytest.Collector'],
         call: 'pytest.CallInfo',
         report: Union['pytest.CollectReport', 'pytest.TestReport'],
     ):
       # https://docs.pytest.org/en/latest/reference/reference.html#pytest.hookspec.pytest_exception_interact
       maybe_debugpy_postmortem(call.excinfo._excinfo)
   
   
   if __name__ == '__main__':
     # yapf: disable
     # pytest.main([__file__], plugins=[])     # <-- Does not hit breakpoints
     pytest.main([__file__], plugins=[PytestDebuggerIntegration])  # <-- The debugger should stop twice 
     # yapf: enable

   I might write and publish this as a separate pytest plugin soon, if you don't mind. What do you think?
4. fabioz commented on Oct 27, 2022

   

   Fabio Zadrozny (fabioz)

   on Oct 27, 2022

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   I might write and publish this as a separate pytest plugin soon, if you don't mind. What do you think?

   I think that'd be ok, I just have 1 note:

   Don't check for debugpy.is_client_connected():... just check if pydevd.get_global_debugger() returns None or if you can't import pydevd (then it'd work with both debugpy as well as pydevd).
5. wookayin commented on Oct 27, 2022

   

   Jongwook Choi (wookayin)

   on Oct 27, 2022

   Last edited by wookayin

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   Don't check for debugpy.is_client_connected():... just check if pydevd.get_global_debugger() returns None or if you can't import pydevd (then it'd work with both debugpy as well as pydevd).

   That's a great point. I have updated the code snippet in #723. Thanks so much!