Add Try Out The Latest Version Of Ruff as a Python TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1837 TILs and counting..._
+_1838 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -1114,6 +1114,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Store And Access Immutable Data In A Tuple](python/store-and-access-immutable-data-in-a-tuple.md)
 - [Strictly Separate Positional And Keyword Arguments](python/strictly-separate-positional-and-keyword-arguments.md)
 - [Test A Function With Pytest](python/test-a-function-with-pytest.md)
+- [Try Out The Latest Version Of Ruff](python/try-out-the-latest-version-of-ruff.md)
 - [Turn Method Into Cached Property On Class Instance](python/turn-method-into-cached-property-on-class-instance.md)
 - [Use pipx To Install End User Apps](python/use-pipx-to-install-end-user-apps.md)
 - [Use `__post_init__` For `dataclass` Validations](python/use-post-init-for-dataclass-validations.md)

python/try-out-the-latest-version-of-ruff.md

@@ -0,0 +1,69 @@
+# Try Out The Latest Version Of Ruff
+
+I have [a Python project](https://github.com/jbranchaud/py-vmt) using
+[`ruff`](https://github.com/astral-sh/ruff) pinned to version `0.15.20`.
+
+```toml
+[dependency-groups]
+dev = [
+    "basedpyright>=1.39.9",
+    "freezegun>=1.5.5",
+    "pytest>=9.0.2",
+    "ruff>=0.15.20",
+    "types-dateparser>=1.3.0.20260211",
+]
+```
+
+All source files are in alignment with the enabled `ruff` rules, so all checks
+pass.
+
+[Simon Willison just posted](https://simonwillison.net/2026/Jul/25/ruff/) about
+a new version of `ruff` (`v0.16.0`) dropping that enables a TON of new rules. He
+mentioned running it against some of his biggest projects and getting a bunch of
+errors.
+
+I was curious to see how my project would fare, so I ran the
+[`uvx`](https://docs.astral.sh/uv/guides/tools/) command that Simon recommended
+in his post.
+
+```bash
+❯ uvx ruff@latest check .
+I001 [*] Import block is un-sorted or un-formatted
+ --> defaults.py:1:1
+  |
+1 | / from datetime import datetime, timezone
+2 | | import time
+  | |___________^
+  |
+help: Organize imports
+  |
+1 + import time
+2 | from datetime import datetime, timezone
+  - import time
+3 |
+  |
+
+UP017 [*] Use `datetime.UTC` alias
+  --> defaults.py:11:36
+
+...
+
+Found 48 errors.
+[*] 41 fixable with the `--fix` option.
+```
+
+Even this small project of mine has 48 errors. Luckily 41 of them can be
+automatically fixed by `ruff`.
+
+It is the `@latest` tag that tells
+[`uvx`](https://docs.astral.sh/uv/guides/tools/) to find and run the latest
+version of `ruff` which currently happens to be `0.16.0`. I can also reliably
+point to a specific version like so:
+
+```bash
+❯ uvx ruff@0.15.14 check .
+All checks passed!
+```
+
+Here is [a listing](https://github.com/astral-sh/ruff/tags) of all tagged `ruff`
+versions.