The documentation for the tempfile module in Python 3.x for the `buffering` option is incorrect:

https://docs.python.org/3/library/tempfile.html

TemporaryFile, NamedTemporaryFile, and SpooledTemporaryFile all take the `buffering` option, which in turn appears to correlate to the Python 2.7 option `bufsize`, which was and continues to be an integer (per the source).

In the 3.x documentation the default signature for TemporaryFile, NamedTemporaryFile, and SpooledTemporaryFile includes `buffering=None`. Actually specifying None as a default for this will cause an exception (`TypeError: an integer is required (got type NoneType)`).

There is a cross-reference in the 3.x tempfile docs to `open` (https://docs.python.org/3/library/functions.html#open) which in turn shows the correct signature to use for `buffering`. Additionally, the source code is clearly documented (https://github.com/python/cpython/blob/master/Lib/tempfile.py)

A good correction would be to ensure `buffering=-1` is documented as the default for the three functions in tempfile, with an additional note explicitly stating that -1 == no buffering, and the existing `open` cross-reference retained.

Hi, will it be good to link the cross-reference for `open`(https://docs.python.org/3/library/functions.html#open) in the documentation?

I think specifically mentioning the usage of the  `buffering` is a better way.

The correction of `buffering=None` --> `buffering=-1` for the defaults definitely needs to happen.

A reference to `open()` is already present in the 3.x documentation: "buffering, encoding and newline are interpreted as for open()."

Given that the `open()` reference already suffices for `encoding` and `newline`, it ought to suffice for `buffering` as well. No extra text beyond that should be necessary (I originally thought that might be good to add, but looking at this now it's clear if you add more to describe `buffering` you'll need to add it for the other two options, and it's all duplicative. Fixing the defaults should suffice.)

This week we were bit by this in production. I foolishly thought that the  docs would give me correct default values... It is worse that it didn't actually occur until we went over the limit.

New changeset b48389d95093c3f912549add8da339edc164bf0d by Sergey Fedoseev in branch 'master':
bpo-33239: Fix default value of 'buffering' parameter in docs of tempfile.* functions (GH-21763)
https://github.com/python/cpython/commit/b48389d95093c3f912549add8da339edc164bf0d

New changeset bf50b0e80a8a0d651af2f953b662eeadd27c7c93 by Miss Islington (bot) in branch '3.8':
bpo-33239: Fix default value of 'buffering' parameter in docs of tempfile.* functions (GH-21763) (GH-22226)
https://github.com/python/cpython/commit/bf50b0e80a8a0d651af2f953b662eeadd27c7c93

New changeset c978be283db768743d995f04414c65439a632bdd by Miss Islington (bot) in branch '3.9':
bpo-33239: Fix default value of 'buffering' parameter in docs of tempfile.* functions (GH-21763) (GH-22225)
https://github.com/python/cpython/commit/c978be283db768743d995f04414c65439a632bdd