🔧 Update package metadata, drop support for Python 3.6, move build internals from Flit to Hatch

[ofek]

Background

Hello there! The Python packaging ecosystem has standardized on the interface for build backends (PEP 517/PEP 660) and the format for metadata declaration (PEP 621/PEP 631).

So, I'm spending my free time updating important projects so that they are modernized and set an example for others 😄

The is a follow-up to pydantic/pydantic#4282

Summary of changes

Metadata

This implements PEP 621 and removes Flit as a development dependency, allowing pip to be used directly which simplifies the contributing workflow and CI/CD. The build backend hatchling (of which I am a maintainer in the PyPA) is now used as that is the default in the official Python packaging tutorial. Hatchling is available on all the major distribution channels such as Debian, Fedora, Arch Linux, conda-forge, Nixpkgs, Alpine Linux, FreeBSD, Gentoo Linux, MacPorts, OpenEmbedded, Spack, etc.

Python support

The earliest supported Python 3 version of Hatchling is 3.7, therefore I've also set that as the minimum here. Python 3.6 is EOL and other build backends like flit-core and setuptools also dropped support. Python 3.6 accounts for 3-4% of downloads in the last month: https://pypistats.org/packages/fastapi

If support is still desired for some reason, I can keep the existing cap and only require 3.7+ in CI/CD.

Documentation

I updated the contributing docs, which accounts for most of the diff. Luckily, they were written in such a way that going from flit to pip didn't alter semantics for any language!

Future

• We now have the ability to ship optional wheels compiled with Mypyc, as Black recently did, to be even faster in benchmarks. Though as @tiangolo mentioned offline, it may be best to wait for the great work @samuelcolvin is doing on Pydantic v2 to be over to be sure we don't cause any disruptions in their test suite.
• We could source the version from Git

[codecov]

Codecov Report

Merging #5240 (90950e3) into master (b2aa359) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #5240   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          540       540           
  Lines        13951     13947    -4     
=========================================
- Hits         13951     13947    -4     

Impacted Files	Coverage Δ
fastapi/encoders.py	100.00% <ø> (ø)
fastapi/concurrency.py	100.00% <100.00%> (ø)
fastapi/dependencies/utils.py	100.00% <100.00%> (ø)

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[github-actions]

📝 Docs preview for commit 0c10260 at: https://62ef63a1ba5a2255983c34e7--fastapi.netlify.app

[ofek]

Ah looks like the 3.6 job is hard coded in this repo's GitHub settings as required.

[github-actions]

📝 Docs preview for commit 8ed4d8a at: https://62fdccd962cae252d9a65fc8--fastapi.netlify.app

[github-actions]

📝 Docs preview for commit ab290a9 at: https://62fdd03bc009ce60bf4787ee--fastapi.netlify.app

[github-actions]

📝 Docs preview for commit 8ee7c5e at: https://632218ad6f7e673abce043d5--fastapi.netlify.app

[ofek]

Suggested change

	with:
	with:
	user: __token__

[tiangolo]

Is it needed? Then maybe the docs in the GitHub Action need an update too?

https://github.com/pypa/gh-action-pypi-publish#usage

[ofek]

Ah, guess not!

[github-actions]

📝 Docs preview for commit c52e2ee at: https://63221a832b16da3418038c4d--fastapi.netlify.app

[github-actions]

📝 Docs preview for commit 90950e3 at: https://63221be7afbe8635f3f1102d--fastapi.netlify.app

[tiangolo]

Awesome job, thanks a lot @ofek! FastAPI is now built with Hatch. 🥚 🐍 😎

Also, Python 3.6 is now officially NOT supported. 🔥