test: automatically generate mise upgrade PRs (#485)

* build: ignore all gemini stuff for now

* build: add workflow for automated mise update PRs

* tmp tweaks to test if the PR workflow operates

* tmp fix to test workflow

* build: don't rely on a specific remote, use hardcoded canonical repo when pushing a mise update

.github/workflows/update-mise.yml

@@ -0,0 +1,34 @@
+name: Update Mise Version
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+env:
+  MISE_ENV: ci
+
+jobs:
+  update-mise:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+        with:
+          fetch-depth: 0
+
+      - uses: jdx/mise-action@5228313ee0372e111a38da051671ca30fc5a96db
+
+      # We manually configure the git user here to support the mise-upgrade script
+      # which handles the commit and PR creation. This keeps the script as the
+      # single source of truth for both local and CI usage.
+      - run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - run: mise run mise-upgrade
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -45,8 +45,9 @@ build/
 
 tmp/
 
+examples/*/size.json
+
 ### AI Tooling ###
 .claude/settings.local.json
 examples/**/.claude
-
-examples/*/size.json
+.gemini/

.mise/tasks/mise-upgrade

@@ -1,4 +1,4 @@
-#!/usr/bin/env zsh
+#!/usr/bin/env bash
 # Description: one-click command to check for a new mise version and create a PR to update core/mise/version.txt.
 
 set -euo pipefail
@@ -6,14 +6,29 @@ set -euo pipefail
 repo_root="$(git rev-parse --show-toplevel)"
 cd "$repo_root"
 
-# Ensure upstream remote exists
-if ! git remote | grep -q '^upstream$'; then
-  echo "Error: 'upstream' remote is not configured. Please add it to fetch the latest changes." >&2
+# Check that we're on the main branch
+current_branch="$(git branch --show-current)"
+if [[ "$current_branch" != "main" ]]; then
+  echo "Error: must be on 'main' branch, currently on '$current_branch'" >&2
   exit 1
 fi
 
-# Fetch latest changes from upstream
-git fetch upstream main
+# Pull latest changes from the canonical railpack remote
+canonical_repo="railwayapp/railpack"
+canonical_url="https://github.com/$canonical_repo"
+remote_name=$(git remote -v | grep "$canonical_repo" | head -n1 | awk '{print $1}')
+
+if [[ -n "$remote_name" ]]; then
+  echo "Updating from remote: $remote_name ($canonical_url)"
+  git fetch "$remote_name" main
+  git pull "$remote_name" main
+  base_branch="$remote_name/main"
+else
+  echo "Updating from URL: $canonical_url"
+  git fetch "$canonical_url" main
+  git pull "$canonical_url" main
+  base_branch="FETCH_HEAD"
+fi
 
 # Require clean working tree for tracked files
 if [[ -n "$(git status --porcelain --untracked-files=no)" ]]; then
@@ -47,7 +62,7 @@ if git show-ref --verify --quiet "refs/heads/$branch"; then
   exit 1
 fi
 
-git switch -c "$branch" upstream/main
+git switch -c "$branch" "$base_branch"
 
 # Write the new version to version.txt
 echo "$latest" > "$file"
@@ -69,6 +84,10 @@ fi
 git add -- "$file"
 git commit -m "update mise $latest"
 
+# Push the branch (needed in CI and good practice locally)
+git push -u origin "$branch"
+
 gh pr create \
+  --repo "$canonical_repo" \
   --title "chore: mise update $latest" \
-  --body "Update mise to $latest" \
+  --body "Update mise to $latest"