Merge master to nightly #400

	# This job merges every commit to `master` into `nightly-testing`, resolving merge conflicts in favor of `nightly-testing`.

	name: Merge master to nightly

	on:
	schedule:
	- cron: '30 /3 * *' # 8AM CET/11PM PT

	jobs:
	merge-to-nightly:
	runs-on: ubuntu-latest
	steps:
	- name: install elan
	run: \|
	set -o pipefail
	curl -sSfL https://github.com/leanprover/elan/releases/download/v3.0.0/elan-x86_64-unknown-linux-gnu.tar.gz \| tar xz
	./elan-init -y --default-toolchain none
	echo "$HOME/.elan/bin" >> "${GITHUB_PATH}"

	- name: Checkout repository
	uses: actions/checkout@v4
	with:
	fetch-depth: 0
	token: ${{ secrets.NIGHTLY_TESTING }}

	- name: Configure Git User
	run: \|
	git config user.name "leanprover-community-mathlib4-bot"
	git config user.email "[email protected]"

	- name: Merge master to nightly favoring nightly changes
	run: \|
	git checkout nightly-testing
	# If the merge goes badly, we proceed anyway via '\|\| true'.
	# CI will report failures on the 'nightly-testing' branch direct to Zulip.
	git merge master --strategy-option ours --no-commit --allow-unrelated-histories \|\| true
	# We aggressively run `lake update`, to avoid having to do this by hand.
	# When Batteries changes break Mathlib, this will likely show up on nightly-testing first.
	lake update
	git add .
	# If there's nothing to do (because there are no new commits from master),
	# that's okay, hence the '\|\| true'.
	git commit -m "Merge master into nightly-testing" \|\| true
	git push origin nightly-testing

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