Feature: lint helper pre push script

CONTRIBUTING.md

@@ -104,11 +104,13 @@ The general workflow for branching is as follows:
 
 6. Make sure the tests are still running with success.
 
-7. Push the changes to `origin` (i.e. your fork)
+7. Run lint locally or set up the pre-push hook: to set up a git pre-push hook that runs lint locally, copy `tools/ci/lint/pre-push.sample` to `.git/hooks/pre-push` and make it executable.
+
+8. Push the changes to `origin` (i.e. your fork)
 
     ```git push origin <branch name>```
 
-8. Create a new Pull Request (see below).
+9. Create a new Pull Request (see below).
 
 #### Creating A Pull Request
 

TESTING.md

@@ -123,6 +123,16 @@ foo.search_paths = {"/usr/lib/lua/lime/hwd/*.lua"}
 
 Coverage is measured using the [luacov](https://keplerproject.github.io/luacov/) library each time the tests are run. The results statistics are merged at `./luacov.stats.out` and a human friendly report is generated at `luacov.report.out`.
 
+## Linting
+
+To ensure code quality and consistency, we have a lint workflow that runs on GitHub Actions.
+You can also run the lint workflow locally before pushing your changes.
+
+To easily run lint locally before pushing, we provide a git pre-push hook:
+* Copy `tools/ci/lint/pre-push.sample` to `.git/hooks/pre-push`
+* Make it executable: `chmod +x .git/hooks/pre-push`
+* This script requires [act](https://github.com/nektos/act) and Docker to run the GitHub Actions workflow locally.
+
 ## Under the hood: tools in detail
 
 As one of the goals is that it must be easy for developers to write, modify and run the tests we created some simple tools to do this:

tools/ci/lint/pre-push.sample

@@ -0,0 +1,23 @@
+#!/bin/sh
+# Run the lint workflow from .github/workflows/lint.yml locally using 'act'
+# Requires: https://github.com/nektos/act (and Docker)
+#
+# Install act:
+#   curl -s https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash -s -- -b /usr/local/bin
+#   On first run, act will ask for an image size. Select "Medium" (~500MB), it is enough.
+#
+# Skip hook: git push --no-verify
+
+# Find act: check PATH first, then common local install locations
+ACT="$(command -v act 2>/dev/null)" \
+	|| ACT="$(git rev-parse --show-toplevel)/bin/act" \
+	|| ACT=""
+
+if [ ! -x "$ACT" ]; then
+	echo "Error: 'act' not found. Install it with:"
+	echo "  curl -s https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash -s -- -b /usr/local/bin"
+	exit 1
+fi
+
+echo "=== Running lint workflow locally ==="
+"$ACT" push -W .github/workflows/lint.yml