prepare-python-release.yml

# Opens the PR that stamps today's CalVer date (e.g. 2026.8.1) onto each Python
# server that changed since its last version bump (#4472). Dispatched by a
# maintainer when preparing a release; the logic, and why Python stays on
# CalVer, is in `scripts/prepare-python-release.mjs`.
#
# It is the Python counterpart of the changesets "Version Packages" PR: the
# version changes in a reviewed PR on the develop branch, and nothing is
# published until a maintainer publishes a GitHub Release (`release.yml`).
#
# The PR targets the branch the workflow was dispatched on, which is `v2/main`
# in the normal flow. It is one of a release's preparation PRs, so it follows
# the same rules as any other PR here: its body opens with `Closes #N` for the
# milestone's release issue (the `issue` input), its branch is named for that
# issue, and it is labeled `v2`. The link is only a cross-reference on
# `v2/main`; the release issue stays open until the Release is published.

name: Prepare Python Release

on:
  workflow_dispatch:
    inputs:
      issue:
        description: "The release issue this PR belongs to (its number, e.g. 4930)"
        required: true
        type: string

jobs:
  prepare:
    timeout-minutes: 10
    if: github.repository_owner == 'modelcontextprotocol'
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write
    steps:
      # The ref this was dispatched on becomes the PR's base, and every PR
      # targets `v2/main`. A run from `main` would open a version PR straight
      # against the release branch, around the milestone merge.
      - name: Refuse a dispatch from any branch but v2/main
        run: |
          if [ "$GITHUB_REF" != "refs/heads/v2/main" ]; then
            echo "::error::Dispatch this workflow on v2/main, not $GITHUB_REF."
            exit 1
          fi

      # Full history: the script finds each package's last version bump with
      # `git log`, and a shallow clone would make every package look new.
      - uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - uses: actions/setup-node@v7
        with:
          node-version: 22

      # The script runs `uv lock` in each package it stamps.
      - name: Install uv
        uses: astral-sh/setup-uv@v7

      - name: Stamp CalVer versions
        run: node scripts/prepare-python-release.mjs > "$RUNNER_TEMP/stamped.txt"

      - name: Check for changes
        id: changes
        run: |
          if git diff --quiet; then
            echo "No Python package needs a version stamp"
            echo "changed=false" >> "$GITHUB_OUTPUT"
          else
            echo "changed=true" >> "$GITHUB_OUTPUT"
          fi

      - name: Create pull request
        if: steps.changes.outputs.changed == 'true'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          BASE: ${{ github.ref_name }}
          ISSUE: ${{ inputs.issue }}
        run: |
          # The input is free text; only a bare issue number may reach the
          # branch name and the PR body.
          case "$ISSUE" in
            '' | *[!0-9]*) echo "issue must be a number, got: '$ISSUE'" >&2; exit 1 ;;
          esac
          DATE=$(date -u +%Y.%-m.%-d)
          BRANCH="v2/chore/$ISSUE-python-calver-$DATE"
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git checkout -b "$BRANCH"
          git add -u
          git commit -m "chore: stamp Python CalVer versions for $DATE"
          git push --force origin "$BRANCH"
          {
            echo "Closes #$ISSUE"
            echo
            echo "Stamps today's CalVer date onto the Python packages that changed since their last version bump:"
            echo
            sed 's/^/- /' "$RUNNER_TEMP/stamped.txt"
            echo
            echo "Generated by the **Prepare Python Release** workflow. Nothing is published until a maintainer publishes a GitHub Release."
            echo
            echo "> [!NOTE]"
            echo "> A PR opened with the workflow token does not trigger CI. Close and reopen this PR to run it."
          } > "$RUNNER_TEMP/pr-body.md"
          # A second run on the same day force-updates the branch, and may
          # stamp a different set of packages; the open PR's body is rewritten
          # to match what the branch now holds.
          EXISTING=$(gh pr list --head "$BRANCH" --state open --json number --jq '.[0].number // empty')
          if [ -n "$EXISTING" ]; then
            gh pr edit "$EXISTING" --body-file "$RUNNER_TEMP/pr-body.md"
            echo "PR #$EXISTING for $BRANCH was already open; its branch and body were updated"
          else
            gh pr create \
              --base "$BASE" \
              --head "$BRANCH" \
              --label v2 \
              --title "chore: stamp Python CalVer versions for $DATE" \
              --body-file "$RUNNER_TEMP/pr-body.md"
          fi