Right now there is no documented way to create a datetime instance with a tzinfo instance. The documented macros all hard code the value Py_None for the tzinfo parameter. Using the PyObject_Call() method instead of the macro for creating a datetime instance is ~5x slower.

In addition, there is no macro or method for getting the tzinfo from an existing datetime instance. Perhaps creating DATE_GET_TZINFO and TIME_GET_TZINFO would be acceptable?

The enhancement 10381 (http://bugs.python.org/issue10381) would also be needed.

I can provide a GitHub PR if that would be helpful. I first want to make sure that such an effort would be appreciated!

Hmm. I never noticed this. In the past I have used the (undocumented) PyDateTimeAPI struct, which the official macros wrap. I'm not sure how official that struct is considering it doesn't show up in the documentation.

I agree that it should be possible to construct TZ-aware datetimes using the official C API, so I guess the question is whether to add a bunch more macros or document the existing struct.

Any progress on this?

So this bug is asking for two things:

1. An official accessor for the `tzinfo` component of an existing datetime, which I think is very reasonable in light of the fact that there are official accessors for all the other components of a datetime.

2. An official constructor for a timezone-aware datetime, which I think basically exists in the form of PyDatetime_CAPI->PyDateTimeAPI->DateTime_FromDateAndTime / ->DateTime_FromDateAndTimeAndFold, and we just need to document it. I think this is basically a separate issue, and I have opened #39604 to track it.

I'm going to rename this bug to focus only on issue #1. I think we can accept a PR adding two new macros. I would suggest calling them:

- PyDateTime_DATE_GET_TZINFO
- PyDateTime_TIME_GET_TZINFO

Please make sure to add tests to any PR you make. See the CapiTest case (https://github.com/python/cpython/blob/d68e0a8a165761604e820c8cb4f20abc735e717f/Lib/test/datetimetester.py#L5914) for examples. You may want to look at the git blame for a few of those tests to see the PRs that they were added in, since part of the tests are defined in a C file.

(As an aside: I don't love that the accessor methods are not available on the struct, since all the "macro-only" code needs to be re-implemented in all other-language bindings. Since the accessors are already all macro-only, though, might as well keep with the tradition for now :P)

> I'm going to rename this bug to focus only on issue #1. I think we can accept a PR adding two new macros. I would suggest calling them:
> - PyDateTime_DATE_GET_TZINFO
> - PyDateTime_TIME_GET_TZINFO

+1 for this.

I have created PR 21633 to add these macros.  Please consider taking a look.

New changeset 2e4dd336e5b50fd30947fdecb605ddcd71f7f6f5 by Zackery Spytz in branch 'master':
bpo-30155: Add macros to get tzinfo from datetime instances (GH-21633)
https://github.com/python/cpython/commit/2e4dd336e5b50fd30947fdecb605ddcd71f7f6f5

pull_requests: + pull_request20775
stage: needs patch -> patch review