Run pre-commit for all files and add instructions for installing pre-commit to dev environments

.github/workflows/pre-commit.yml

@@ -9,6 +9,10 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
+    - id: changed-files
+      uses: tj-actions/changed-files@v47
     - uses: actions/checkout@v3
     - uses: actions/setup-python@v3
     - uses: pre-commit/[email protected]
+      with:
+        extra_args: --files ${{ steps.changed-files.outputs.all_changed_files }}

.pre-commit-config.yaml

@@ -1,4 +1,3 @@
-files: _shared_utils
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.4.0
@@ -12,7 +11,7 @@ repos:
     rev: 7.3.0
     hooks:
       - id: flake8
-        args: ["--ignore=E501,W503,F403,F405,E711,E712,E231,E702,E203"] 
+        args: ["--ignore=E501,W503,F403,F405,E711,E712,E231,E702,E203"]
         # E711: comparison to None should be 'if cond is not None:' (siuba filtering requires we use != None and not is not)
         # E712: line too long and line before binary operator (black is ok with these), assign lambda expression OK, comparison to True with is (siuba uses ==)
         # E231: missing whitespace after colon (we don't want white space when setting gs://)

README.md

@@ -1,14 +1,27 @@
 # data-analyses
 Place for sharing quick reports, and works in progress
 
-This repository is for quick sharing of works in progress and simple analyses. 
+This repository is for quick sharing of works in progress and simple analyses.
 For collaborative short-term tasks, create a new folder and work off a separate branch.
 For longer-term projects, consider making a new repository!
 
 ## Using this Repo
 
 * Use [this link](https://docs.calitp.org/data-infra/analytics_tools/saving_code.html#onboarding-setup) to get started in JupyterHub, set up SSH, and start commiting to the repo!
 
+### Contributing
+#### Pre-commit
+
+This repository uses pre-commit hooks to format code, including [Black](https://black.readthedocs.io/en/stable/index.html). This ensures baseline consistency in code formatting.
+
+> [!IMPORTANT]
+> Before contributing to this project, please install pre-commit locally by running `pip install pre-commit` and `pre-commit install` in the root of the repo.
+
+Once installed, pre-commit checks will run before you can make commits locally. If a pre-commit check fails, it will need to be addressed before you can make your commit. Many formatting issues are fixed automatically within the pre-commit actions, so check the changes made by pre-commit on failure -- they may have automatically addressed the issues that caused the failure, in which case you can simply re-add the files, re-attempt the commit, and the checks will then succeed.
+
+Installing pre-commit locally saves time dealing with formatting issues on pull requests. There is a [GitHub Action](./.github/workflows/lint.yml)
+that runs pre-commit on all files, not just changed ones, as part of our continuous integration.
+
 ## Quick Links - Get Started in Data Analysis
 
 #### Data Analytics Documentation - Welcome