Upgrading Python

Upgrading Python

Django 6.0 needs Python 3.12. When the target Django needs a newer Python than your project uses, the report starts with what all your dependencies need on it, not only the Django-related ones. A C extension without a wheel for the new Python is the most common surprise of a Django upgrade.

Python 3.12 first (2)
  These dependencies need something before they run on Python 3.12.
  ↑ numpy            1.22.4 → 1.26.0  1.22.4 no wheel for Python 3.12, pip builds it from source
  ↑ psycopg2-binary  2.9.3 → 2.9.9    2.9.3 no wheel for Python 3.12, pip builds it from source
  3 more dependencies run on Python 3.12, all pure Python.
  1 says nothing about Python versions: pycrypto.
  Django 4.2.7 does not declare Python 3.12, 4.2.8 does: update Django 4.2 first.

When it runs

--python-target	Checks
auto (default)	The Python the target Django needs, when your project uses an older one. Your project's Python must be known, see Dependency sources.
3.13, …	That Python, whatever Django needs. Useful for a Python upgrade on its own.
none	Nothing.

How a release is judged on a Python

In this order:

1. A Requires-Python that excludes it means no.
2. A Programming Language :: Python :: 3.12 classifier means yes.
3. A wheel built for it (cp312) means yes.
4. An abi3 wheel for an older Python, or a pure-Python wheel (py3-none-any), runs on it too.
5. Wheels only for other Pythons mean pip builds it from source: that needs a compiler and headers and often fails. Without a source distribution it cannot be installed at all, which means no.
6. Otherwise the release says nothing about Python versions.

Wheels count when they install on CPython under Linux on x86_64, where Django apps run. PyPy and free-threading (cp313t) wheels do not count.

What the section shows

• Rows for dependencies whose installed release excludes the Python or would be built from source, with the oldest newer release that runs on it, and those no release fixes (blocked).
• A note goes together with the switch to Python 3.12 when that release no longer runs on the Python you use today.
• One line counts the dependencies that run on it already; another names those whose release says nothing about Python at all (old sdist-only packages).
• One line says whether your Django patch release declares the Python, or which patch of your series first does.
• In the Django plan, an upgrade whose release excludes the new Python says so on its row.

The installed releases come from the cache the Django check already filled. A release history is only fetched for a dependency that needs an upgrade.

In CI

django-upgrade-report --fail-on-python blocked

fails when a dependency has no release that runs on the new Python. The GitHub Action has the inputs python-target and fail-on-python, and the output python-blocked. The JSON report has the section under python.