# Copyright 2026 RustFS Team
# SPDX-License-Identifier: Apache-2.0

name: Gateway Integration Sync

# Merges `main` into the long-lived `gateway/integration` branch every weekday
# so the s3s -> gateway migration (rustfs/backlog#2734, task T0.1 in #2736)
# never accumulates merge debt. A clean merge lands as a `--no-ff` merge commit
# pushed straight to the branch. A conflicting merge is aborted and fails the
# run after its summary records the source and target SHAs, run URL, and exact
# conflicting paths. It creates no sync branch or pull request. Resolve the
# merge in an isolated worktree based on the latest target, preserve the
# two-parent merge commit, and push only after the required checks pass and the
# target still matches the merge's first parent. If the target moves, restart
# from its new head.
#
# Write scope: only `gateway/integration` is ever pushed. The push uses a
# one-hour installation token of the organisation's GitHub App (contents:
# write) because that app is the only non-admin bypass actor of the
# `gateway/integration` ruleset; GITHUB_TOKEN cannot be a ruleset bypass actor,
# so it cannot push through the required reviews and checks. GITHUB_TOKEN is
# read-only here.
#
# `schedule` fires only from the default branch, so the cron is live once this
# file exists on `main`. `workflow_dispatch` runs from any ref that carries the
# file and always acts on `gateway/integration`.

on:
  schedule:
    - cron: "0 2 * * 1-5" # Weekdays 02:00 UTC
  workflow_dispatch:
    inputs:
      source_ref:
        description: >-
          Branch to merge into gateway/integration. The schedule always merges
          main; only the conflict acceptance test (rustfs/backlog#2736) sets
          another branch.
        required: false
        default: main
        type: string

permissions:
  contents: read

concurrency:
  group: ${{ github.workflow }}
  cancel-in-progress: false

env:
  TARGET_BRANCH: gateway/integration

jobs:
  sync:
    name: Merge main into gateway/integration
    if: github.repository == 'rustfs/rustfs'
    runs-on: ubuntu-latest
    timeout-minutes: 15
    steps:
      - name: Create the branch push token
        id: push-token
        uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1 # v3
        with:
          app-id: ${{ vars.CLA_BOT_APP_ID }}
          private-key: ${{ secrets.CLA_BOT_APP_PRIVATE_KEY }}
          owner: ${{ github.repository_owner }}
          repositories: rustfs
          permission-contents: write

      - name: Checkout gateway/integration
        uses: actions/checkout@f548e57e544e1ff5a4c46bf1e1b8685f8e4a348a # v7
        with:
          # persist-credentials-exempt: this checkout's token IS the push
          # credential — the merge commit and the sync branch are pushed with it
          # below. It is a one-hour installation token scoped to contents.
          ref: gateway/integration
          fetch-depth: 0
          token: ${{ steps.push-token.outputs.token }}

      - name: Configure the bot identity
        run: |
          git config user.name "rustfs-cla-assistant[bot]"
          git config user.email "273121464+rustfs-cla-assistant[bot]@users.noreply.github.com"

      - name: Merge the source branch
        id: merge
        env:
          SOURCE_REF: ${{ inputs.source_ref || 'main' }}
          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        run: |
          set -euo pipefail
          if ! [[ "$SOURCE_REF" =~ ^[A-Za-z0-9][A-Za-z0-9._/-]*$ ]] \
            || [[ "$SOURCE_REF" == *..* ]] \
            || [[ "$SOURCE_REF" == "$TARGET_BRANCH" ]]; then
            echo "::error::refusing source_ref '${SOURCE_REF}'"
            exit 1
          fi
          git fetch origin "refs/heads/${SOURCE_REF}:refs/remotes/origin/${SOURCE_REF}"
          source_sha=$(git rev-parse "origin/${SOURCE_REF}")
          target_sha=$(git rev-parse HEAD)
          {
            echo "source_ref=${SOURCE_REF}"
            echo "source_sha=${source_sha}"
            echo "target_sha=${target_sha}"
          } >> "$GITHUB_OUTPUT"
          if git merge --no-ff --no-edit "origin/${SOURCE_REF}"; then
            if [[ "$(git rev-parse HEAD)" == "$target_sha" ]]; then
              echo "result=up-to-date" >> "$GITHUB_OUTPUT"
              echo "\`${TARGET_BRANCH}\` already contains \`${SOURCE_REF}\` (${source_sha}); nothing to push." >> "$GITHUB_STEP_SUMMARY"
            else
              echo "result=merged" >> "$GITHUB_OUTPUT"
            fi
            exit 0
          fi
          conflicts=$(git diff --name-only --diff-filter=U)
          if [[ -z "$conflicts" ]]; then
            git merge --abort || true
            echo "::error::git merge failed without reporting conflicting paths; this is not a conflict"
            exit 1
          fi
          {
            echo "## Gateway integration sync stopped on conflicts"
            echo
            echo "- Run: ${RUN_URL}"
            echo "- Source: \`${SOURCE_REF}\` at ${source_sha}"
            echo "- Target: \`${TARGET_BRANCH}\` at ${target_sha}"
            echo
            echo "Conflicting files:"
            printf '%s\n' "$conflicts" | sed 's/^/- /'
          } >> "$GITHUB_STEP_SUMMARY"
          git merge --abort
          echo "::error::${SOURCE_REF} cannot be merged cleanly into ${TARGET_BRANCH}; no branch or pull request was created"
          exit 1

      - name: Push the merge commit
        if: steps.merge.outputs.result == 'merged'
        env:
          SOURCE_REF: ${{ steps.merge.outputs.source_ref }}
          SOURCE_SHA: ${{ steps.merge.outputs.source_sha }}
        run: |
          set -euo pipefail
          git push origin HEAD:refs/heads/gateway/integration
          echo "Merged \`${SOURCE_REF}\` (${SOURCE_SHA}) into \`${TARGET_BRANCH}\` as $(git rev-parse HEAD)." >> "$GITHUB_STEP_SUMMARY"

  alert-on-failure:
    name: Alert on scheduled failure
    needs: [sync]
    # Same ci-8 mechanism audit.yml and coverage.yml use: a scheduled run that
    # could not push or encountered merge conflicts must not stay visible only
    # in the Actions tab.
    if: github.repository == 'rustfs/rustfs' && (always() && github.event_name == 'schedule' && contains(needs.*.result, 'failure'))
    runs-on: ubuntu-latest
    timeout-minutes: 10
    permissions:
      contents: read
      issues: write
    steps:
      - uses: actions/checkout@f548e57e544e1ff5a4c46bf1e1b8685f8e4a348a # v7
        with:
          persist-credentials: false
      - name: Open or update failure-tracking issue
        uses: ./.github/actions/schedule-failure-issue
        with:
          github-token: ${{ secrets.BACKLOG_ISSUE_TOKEN }}