Update Lean Toolchain Version #283

	name: Update Lean Toolchain Version
	on:
	schedule:
	- cron: '44 * * * *'
	workflow_dispatch:

	permissions: write-all

	jobs:
	mathlibtoday:
	name: Update Lean Nightly
	permissions: write-all
	runs-on: ubuntu-latest
	steps:
	- name: Checkout 🛎️
	uses: actions/checkout@v4
	with:
	token: ${{secrets.PAT}}

	- name: Install elan 🕑
	run: \|
	set -o pipefail
	curl https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh -sSf \| sh -s -- --default-toolchain none -y
	~/.elan/bin/lean --version
	echo "$HOME/.elan/bin" >> $GITHUB_PATH

	- name: Install uv
	run: \|
	pip install uv

	- name: Get Lean Nightly Date
	id: leandate
	run: \|
	echo date=`uv run -q .github/workflows/get_lean_version.py` >> $GITHUB_OUTPUT

	- id: check-branch-exists
	uses: GuillaumeFalourd/branch-exists@v1.1
	with:
	branch: auto-lean-update-${{steps.mldate.outputs.date}}

	- if: steps.check-branch-exists.outputs.exists == 'true'
	run: Skip any updates

	- name: Set Lean Toolchain Date
	run: \|
	echo "## lean-toolchain"
	sed -e "s/nightly.*/${{steps.leandate.outputs.date}}/" -i lean-toolchain
	cat lean-toolchain
	lake update --no-cache
	env:
	LAKE_NO_CACHE: true

	- name: Create Pull Request
	id: create-pr
	uses: peter-evans/create-pull-request@v7
	with:
	title: "${{steps.leandate.outputs.date}} lean nightly update"
	branch: "auto-lean-update-${{steps.leandate.outputs.date}}"
	body: "automatic update of lean via GitHub action."
	token: ${{secrets.PAT}}

	- name: Enable Pull Request Automerge
	run: gh pr merge --squash --auto ${{steps.create-pr.outputs.pull-request-number}}
	env:
	GH_TOKEN: ${{secrets.PAT}}

Provide feedback