Add Another Way To Mark Keyword-Only Dataclass Fields 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).
 
-_1844 TILs and counting..._
+_1846 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -486,6 +486,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Capture An Output Value For Use In A Later Step](github-actions/capture-an-output-value-for-use-in-a-later-step.md)
 - [Disable A Workflow With The gh CLI](github-actions/disable-a-workflow-with-the-gh-cli.md)
 - [Reference An Encrypted Secret In An Action](github-actions/reference-an-encrypted-secret-in-an-action.md)
+- [Run Schedule Action To Commit Regular Updates](github-actions/run-scheduled-action-to-commit-regular-updates.md)
 - [Trigger A Workflow Via An API Call](github-actions/trigger-a-workflow-via-an-api-call.md)
 - [Use Labels To Block PR Merge](github-actions/use-labels-to-block-pr-merge.md)
 
@@ -1072,6 +1073,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Access Most Recent Return Value In REPL](python/access-most-recent-return-value-in-repl.md)
 - [Access SQLite Result Values By Name With Row Factory](python/access-sqlite-result-values-by-name-with-row-factory.md)
 - [Access Variables Outside Loop Scope](python/access-variables-outside-loop-scope.md)
+- [Another Way To Mark Keyword-Only Dataclass Fields](python/another-way-to-mark-keyword-only-dataclass-fields.md)
 - [Argument Defaults Are Evaluated When Function Is Defined](python/argument-defaults-are-evaluated-when-function-is-defined.md)
 - [Assert Is Only A Development Check](python/assert-is-only-a-development-check.md)
 - [Avoid Modification With Frozen Dataclass](python/avoid-modification-with-frozen-dataclass.md)

github-actions/run-scheduled-action-to-commit-regular-updates.md

@@ -0,0 +1,58 @@
+# Run Scheduled Action To Commit Regular Updates
+
+The quintessential example of what GitHub Actions are used for is running CI
+tasks like the test suite, type checker, linter, etc. Each CI step runs to
+completion and either passes or fails and you see the results in the GitHub PR
+interface. That's a great use case, but far from the only one. GitHub Actions
+are a much more general-purpose execution environment that can be used for much
+more.
+
+Here is a recent example that expanded my mind a bit on what is possible with
+GitHub actions. Imagine a GitHub Action that is scheduled to run once a day, it
+executes a script that might make changes to the repo itself (e.g. the
+`README.md`), and then commits those changes (self-updating the repo).
+
+Here is a minimal version of a workflow that does that:
+
+```yaml
+on:
+  schedule:
+    - cron: '17 11 * * *' # daily at 11:17 UTC (06:17 CT)
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4 # get the repo + push credentials
+
+      - run: ./bin/regenerate_readme.sh # apply updates to README
+
+      - run: |
+          git config user.name  "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add -A README.md
+          git diff --staged --quiet || {
+            git commit -m "chore: regenerate README with latest updates"
+            git push
+          } # commit updates to README if there are any, otherwise no-op
+```
+
+Once a day at 11:17 UTC, GitHub Actions will run this workflow which is made up
+of a single job with permissions to write to the repo.
+
+- First, it checks out the repo in the job container which includes push
+credentials.
+- Then it runs a script that might update the README (e.g. maybe based on other
+things that have since been committed to the repo).
+- Last, it attempts to stage any changes the script made to the README. If there
+are any, then it will commit them with that generic commit message. Finally it
+will push that commit to the main branch.
+
+If this all sounds a bit untethered from a real-world example, then take a look
+at how I use this exact pattern to [apply daily updates to my GitHub Profile
+README](https://github.com/jbranchaud/jbranchaud/blob/main/.github/workflows/update-tils.yml)
+based on the latest [TILs](https://github.com/jbranchaud/til) I have written.

python/another-way-to-mark-keyword-only-dataclass-fields.md

@@ -0,0 +1,47 @@
+# Another Way To Mark Keyword-Only Dataclass Fields
+
+In [Configure Other Attributes Of Dataclass
+Field](configure-other-attributes-of-dataclass-field), I showed how the
+[`dataclasses.field`](https://docs.python.org/3/library/dataclasses.html#dataclasses.field)
+constructor function can be used. One of the parameters I demonstrated was
+`kw_only`. Each field constructed with `kw_only=True` will be required to be
+passed as a keyword-only parameter when constructing an instance of that
+`dataclass`.
+
+Another way to specify keyword-only parameters with `dataclass` fields is to
+segment them with `KW_ONLY`. This sentinel value can be included as a
+pseudo-field where all fields that come after it are treated as keyword-only.
+
+Translating the example from that other post would look like this:
+
+```python
+from dataclasses import dataclass, field, KW_ONLY
+from datetime import datetime
+
+@dataclass
+class Session:
+    start_time: datetime
+    project_name: str
+    _: KW_ONLY
+    tags: list[str] = field(default_factory=list, kw_only=True)
+    end_time: datetime | None = None
+
+    # ...
+
+sesh1 = Session(start1, "my-project", tags=["pytorch", "numpy"])
+sesh2 = Session(start2, "other-project", end_time=datetime.now())
+```
+
+The field whose value is `KW_ONLY` is only used to signal that keyword-only
+boundary. It does not itself become a field of the dataclass.
+
+On the one hand I like this approach because it feels closer to [the way this is
+signaled in standard function definition
+syntax](force-remaining-arguments-to-be-named.md).
+
+```python
+def build_session(start_time, project_name, *, tags, end_time=None)
+```
+
+On the other hand, it feels like magic `dataclass` syntax whereas the
+`kw_only=True` parameter is more explicit.