Set sys.last_value / sys.last_exc before entering the debugger #380
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**Background:** In commit 6eae532, we introduced a new utility in pyflyby named `saveframe`. This utility is designed to save error stack frames upon an exception. Users can also enter a debugger after an exception (using ipdb.pm()) and call `saveframe` to dump a specific frame. `saveframe` relies on `sys.last_value` (or `sys.last_exc` in Python 3.12) to retrieve the last exception object raised. These attributes are automatically set by Python after an uncaught exception occurs. **Issue:** When a user executes a script or command using `py <some_script_or_command>` or employs the `@debug_on_exception` decorator, the exception is caught, and the debugger is invoked. Consequently, `sys.last_value` (or `sys.last_exc`) is not set. If the user attempts to call `saveframe` within the debugger, it fails because the necessary exception information is unavailable. **Solution:** In this commit, we modified the code to explicitly set `sys.last_value` (or `sys.last_exc`) after an exception is caught and before entering the debugger. This ensures that users can directly enter the debugger and successfully call the `pyflyby.saveframe` function. Request: PyInf#12047
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cc @sac111gp |
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Background:
In commit 6eae532, we introduced a new utility in pyflyby named
saveframe. This utility is designed to save error stack frames upon an exception. Users can also enter a debugger after an exception (using ipdb.pm()) and callsaveframeto dump a specific frame.saveframerelies onsys.last_value(orsys.last_excin Python 3.12) to retrieve the last exception object raised. These attributes are automatically set by Python after an uncaught exception occurs.Issue:
When a user executes a script or command using
py <some_script_or_command>or employs the@debug_on_exceptiondecorator, the exception is caught, and the debugger is invoked. Consequently,sys.last_value(orsys.last_exc) is not set. If the user attempts to callsaveframewithin the debugger, it fails because the necessary exception information is unavailable.Solution:
In this commit, we modified the code to explicitly set
sys.last_value(orsys.last_exc) after an exception is caught and before entering the debugger. This ensures that users can directly enter the debugger usingpy, and successfully call thepyflyby.saveframefunction.Request: PyInf#12047