August 11, 2025

#444 Begone Python of Yore!

25 minutes

Topics covered in this episode:

Coverage.py regex pragmas

* Python of Yore*

* nox-uv*

* A couple Django items*

Extras

Joke

Watch on YouTube

About the show

Sponsored by DigitalOcean: pythonbytes.fm/digitalocean-gen-ai Use code DO4BYTES and get $200 in free credit

Connect with the hosts

Michael: @[email protected] / @mkennedy.codes (bsky)

Brian: @[email protected] / @brianokken.bsky.social

Show: @[email protected] / @pythonbytes.fm (bsky)

Join us on YouTube at pythonbytes.fm/live to be part of the audience. Usually Monday at 10am PT. Older video versions available there too.

Finally, if you want an artisanal, hand-crafted digest of every week of the show notes in email form? Add your name and email to our friends of the show list, we'll never share it.

Brian #1: Coverage.py regex pragmas

Ned Batchelder

The regex implementation of how coverage.py recognizes pragmas is pretty amazing.

It’s extensible through plugins

covdefaults adds a bunch of default exclusions, and also platform- and version-specific comment syntaxes.

coverage-conditional-plugin gives you a way to create comment syntaxes for entire files, for whether other packages are installed, and so on.

A change from last year (as part of coverage.py 7.6 allows multiline regexes, which let’s us do things like:

Exclude an entire file with \\A(?s:.*# pragma: exclude file.*)\\Z

Allow start and stop delimiters with # no cover: start(?s:.*?)# no cover: stop

Exclude empty placeholder methods with ^\\s*(((async )?def .*?)?\\)(\\s*->.*?)?:\\s*)?\\.\\.\\.\\s*(#|$)

See Ned’s article for explanations of these

Michael #2: Python of Yore

via Matthias

Use YORE: ... comments to highlight CPython version dependencies.

# YORE: EOL 3.8: Replace block with line 4.

if sys.version_info < (3, 9):

from astunparse import unparse

else:

from ast import unparse

Then check when they go out of support:

$ yore check --eol-within '5 months'

./src/griffe/agents/nodes/_values.py:11: Python 3.8 will reach its End of Life within approx. 4 months

Even fix them with fix .

Michael #3: nox-uv

via John Hagen

What nox-uv does is make it very simple to install uv extras and/or dependency groups into a nox session's virtual environment.

The versions installed are constrained by uv's lockfile meaning that everything is deterministic and pinned.

Dependency groups make it very easy to install only want is necessary for a session (e.g., only linting dependencies like Ruff, or main dependencies + mypy for type checking).

Brian #4: A couple Django items

Stop Using Django's squashmigrations: There's a Better Way

Johnny Metz

Resetting migrations is sometimes the right thing.

Overly simplified summary: delete migrations and start over

dj-lite

Adam Hill

Use SQLite in production with Django

“Simplify deploying and maintaining production Django websites by using SQLite in production. dj-lite helps enable the best performance for SQLite for small to medium-sized projects. It requires Django 5.1+.”

Extras

Brian:

Test & Code 237 with Sebastian Ramirez on FastAPI Cloud

pythontest.com: pytest fixtures nuts and bolts - revisited

Michael:

New course: Just Enough Python for Data Scientists

My live stream about uv is now on YouTube

Cursor CLI: Built to help you ship, right from your terminal.

Joke: Copy/Paste

...more

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By Michael Kennedy and Brian Okken

4.7

212212 ratings

August 11, 2025

#444 Begone Python of Yore!

25 minutes

Topics covered in this episode:

Coverage.py regex pragmas

* Python of Yore*

* nox-uv*

* A couple Django items*

Extras

Joke

Watch on YouTube

About the show

Sponsored by DigitalOcean: pythonbytes.fm/digitalocean-gen-ai Use code DO4BYTES and get $200 in free credit

Connect with the hosts

Michael: @[email protected] / @mkennedy.codes (bsky)

Brian: @[email protected] / @brianokken.bsky.social

Show: @[email protected] / @pythonbytes.fm (bsky)

Join us on YouTube at pythonbytes.fm/live to be part of the audience. Usually Monday at 10am PT. Older video versions available there too.

Finally, if you want an artisanal, hand-crafted digest of every week of the show notes in email form? Add your name and email to our friends of the show list, we'll never share it.

Brian #1: Coverage.py regex pragmas

Ned Batchelder

The regex implementation of how coverage.py recognizes pragmas is pretty amazing.

It’s extensible through plugins

covdefaults adds a bunch of default exclusions, and also platform- and version-specific comment syntaxes.

coverage-conditional-plugin gives you a way to create comment syntaxes for entire files, for whether other packages are installed, and so on.

A change from last year (as part of coverage.py 7.6 allows multiline regexes, which let’s us do things like:

Exclude an entire file with \\A(?s:.*# pragma: exclude file.*)\\Z

Allow start and stop delimiters with # no cover: start(?s:.*?)# no cover: stop

Exclude empty placeholder methods with ^\\s*(((async )?def .*?)?\\)(\\s*->.*?)?:\\s*)?\\.\\.\\.\\s*(#|$)

See Ned’s article for explanations of these

Michael #2: Python of Yore

via Matthias

Use YORE: ... comments to highlight CPython version dependencies.

# YORE: EOL 3.8: Replace block with line 4.

if sys.version_info < (3, 9):

from astunparse import unparse

else:

from ast import unparse

Then check when they go out of support:

$ yore check --eol-within '5 months'

./src/griffe/agents/nodes/_values.py:11: Python 3.8 will reach its End of Life within approx. 4 months

Even fix them with fix .

Michael #3: nox-uv

via John Hagen

What nox-uv does is make it very simple to install uv extras and/or dependency groups into a nox session's virtual environment.

The versions installed are constrained by uv's lockfile meaning that everything is deterministic and pinned.

Dependency groups make it very easy to install only want is necessary for a session (e.g., only linting dependencies like Ruff, or main dependencies + mypy for type checking).

Brian #4: A couple Django items

Stop Using Django's squashmigrations: There's a Better Way

Johnny Metz

Resetting migrations is sometimes the right thing.

Overly simplified summary: delete migrations and start over

dj-lite

Adam Hill

Use SQLite in production with Django

Extras

Brian:

Test & Code 237 with Sebastian Ramirez on FastAPI Cloud

pythontest.com: pytest fixtures nuts and bolts - revisited