When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

Thanks for the feedback, @gpshead!

I'm not happy with the first draft. It's not elegant. It's easier to track builtin constructors in C and map them directly in _hashopenssl.c.

Seems that commit 933dfd7 introduced some reference leaks:

commit 933dfd7
Author: Christian Heimes christian@python.org
Date: Sat Mar 27 14:55:03 2021 +0100

[bpo-40645](https://bugs.python.org/issue40645): use C implementation of HMAC (GH-24920)

𓋹 ./python.exe -m test test_hashlib -R 3:3
0:00:00 load avg: 5.67 Run tests sequentially
0:00:00 load avg: 5.67 [1/1] test_hashlib
beginning 6 repetitions
123456
......
test_hashlib leaked [1, 1, 1] references, sum=3
test_hashlib failed

== Tests result: FAILURE ==

1 test failed:
test_hashlib

Total duration: 8.7 sec
Tests result: FAILURE

- [x] fix tests
- [ ] add test scenarios for old/new code.

Signed-off-by: Christian Heimes <christian@python.org>

Lib/hashlib.py | 1 +
Lib/hmac.py | 86 +++++++-----
Lib/test/test_hmac.py | 114 +++++++++-------
.../2021-03-19-10-22-17.bpo-40645.5pXhb-.rst | 2 +
Modules/_hashopenssl.c | 150 +++++++++++++++++++--
Modules/clinic/_hashopenssl.c.h | 38 +-----
6 files changed, 267 insertions(+), 124 deletions(-)
create mode 100644 bpo-40645.5pXhb-.rst">Misc/NEWS.d/next/Library/2021-03-19-10-22-17.bpo-40645.5pXhb-.rst

Opened #25063 to address it