make os._wrap_close not inherit from TextIOWrapper

[tungol]

Methods are passed through at runtime via __getattr__

related to #3968

I think is more correct, but we may be getting into territory where duplication of effort becomes a question. Is getting the inheritance right worth maintaining the extra lines of code in this case?

I could see no reason why TextIOWrapper was imported as _TextIOWrapper, other than that import is extremely old; I didn't check but I suspect the current rules around as imports were not as established at the time, and the underscore was added to prevent it appearing in os's namespace. I normalized to just a normal import for that reason.

[tungol]

We could also consider leaving some of the methods out of the stubs since the full scope of what's available on _wrap_close is basically undocumented. reconfigure in particular seems unlikely to be useful, and the same goes for seeking related methods. Actual documentation just says:

The return value is an open file object connected to the pipe, which can be read or written depending on whether mode is 'r' (default) or 'w'. [...] The returned file object reads or writes text strings rather than bytes.

[tungol]

I've kept thinking about this one, and the more I think about it the more it seems like picking only a subset of TextIOWrapper's methods to put in the stubs seems like a reasonable idea. If anyone else has thoughts on that, I'd love to hear them.

[tungol]

mypy-primer revealed only read(): #12782 (comment)

I'm not too surprised - the primary use of os.popen probably happens in smaller scripts than what make it into mypy-primer's corpus.

[srittau]

I'm fine with proxying all methods, but if you want to go for a smaller subset (at least until someone complains), I'm fine with that, too.

[tungol]

I looked through the first five pages of github code search results for os.popen and saw examples of read, readline, and readlines being used, as well as iteration, but nothing else.

Let's go with the smaller subset to start and see if anyone notices. I updated to include the read* and write* methods, but leave out the rest.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉