Documentation

While messing around trying to find undocumented module attributes, I noticed that csv.__all__ contains both __doc__ and __version__. Those inclusions are themselves weird, but I further noticed this:

from _csv import Error, __version__, writer, reader, register_dialect, \
                 unregister_dialect, get_dialect, list_dialects, \
                 field_size_limit, \
                 QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE, \
                 QUOTE_STRINGS, QUOTE_NOTNULL, \
                 __doc__

Note that both attributes are imported from the underlying _csv module. Furthermore, the __doc__ attribute is pretty extensive.

I see no particular reason either attribute needs to be defined in the underlying C module. In particular, maintaining a docstring in C (with its constrainged multi-line string syntax) is much more difficult than in Python (with its rather nice triple-quoted string syntax).

I hope I wasn't the ultimate source of this problem. I suspect that in pulling non-performance-critical bits out of the old CSV module (when it was written entirely in C) these two attributes were just missed.

Linked PRs

• gh-114123: migrate docstring from _csv to csv #114124