StandardError in Python 2 -> 3

[Steven D'Aprano]

The exception hierarchy in Python 3 is shallower than in Python 2.

Here is a partial list of exceptions in Python 2:


BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- StandardError
| +-- AttributeError
| +-- ImportError
| +-- NameError
| +-- TypeError
| +-- ValueError
+-- Warning

and the same again in Python 3:

BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- AttributeError
+-- ImportError
+-- NameError
+-- SystemError
+-- TypeError
+-- ValueError
+-- Warning


Note that StandardError is gone.

Does anyone use StandardError in their own code? In Python 2, I normally
inherit from StandardError rather than Exception. Should I stop and just
inherit from Exception in both 2 and 3?

 

[Ian Kelly]

Does anyone use StandardError in their own code? In Python 2, I normally
inherit from StandardError rather than Exception. Should I stop and just
inherit from Exception in both 2 and 3?

According to the docs, StandardError is for built-in exceptions, and
user-defined exceptions are meant to inherit from Exception.

http://docs.python.org/2/library/exceptions.html#exceptions.Exception