On 2019-11-18 10:49, Random832 wrote:
I would say open() is arguably a wart. Had context managers existed in the language all along, it should not be possible to do anything that creates an open-ended future requirement to do something (i.e. "require that the returned object gets closed at some stage") without either using a with statement or writing code to manually call __enter__ and __exit__. The likely most common case being a class that holds an open file, which should really have its own context manager that forwards to the file's.
I agree. I think this discussion wouldn't be necessary if there were a context manager that was like open() but opened the file in __enter__ and closed it in __exit__. I would go so far as to say I think it would be a good idea to add such a context manager to Python and deprecate open().
When I teach Python, I don't really even explain open() in isolation to students, I just tell them to always use it with a with statement. If I see code that uses open() outside a with statement it's a red flag to me. These hypothetical cases where you might want to use open() outside a with statement seem, to me, to be fairly esoteric. The best policy is for every file-opening operation to occur as part of a context manager,