[ Python 常見問題 ] Is it possible to automatically break into the debugger when a exception is thrown?

 Source From Here

Question
Is there a way to automatically start break into the debugger (import pdb; pdb.set_trace()) whenever a exception is thrown to inspect the local stack?

HowTo
I found what I was looking for in an answer to What is the simplest way of using Python pdb to in...use of an unhandled exception?:
- test.py

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1. #!/usr/bin/env python3  
2. import pdb  
3. import sys  
4. import functools  
5.   
6.   
7. def debug_on(*exceptions):  
8.     if not exceptions:  
9.         exceptions = (Exception, )  
10.     def decorator(f):  
11.         @functools.wraps(f)  
12.         def wrapper(*args, **kwargs):  
13.             try:  
14.                 return f(*args, **kwargs)  
15.             except exceptions:  
16.                 pdb.post_mortem(sys.exc_info()[2])  
17.         return wrapper  
18.     return decorator  
19.   
20. @debug_on()  
21. def buggy_function():  
22.     print("About to cause exception!")  
23.     raise Exception("Something wrong!")  
24.     print("Unreachable...")  
25.   
26. if __name__ == '__main__':  
27.     buggy_function()  

Let's test it:

# ./test.py
About to cause exception!
> /tmp/test.py(23)buggy_function()
-> raise Exception("Something wrong!")
(Pdb) list

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1. 18         return decorator  
2. 19  
3. 20     @debug_on()  
4. 21     def buggy_function():  
5. 22         print("About to cause exception!")  
6. 23  ->     raise Exception("Something wrong!")  
7. 24         print("Unreachable...")  
8. 25  
9. 26     if __name__ == '__main__':  
10. 27         buggy_function()  
11. [EOF]  

(Pdb) exit()