# 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 surfaced as
# a pull request from `sync/<source>-<date>`, whose head is the un-merged
# source commit, so the conflict is resolved the same day, in review, with no
# other change riding along. The run itself stays green in that case: the pull
# request is the signal. Any other failure (push rejected, pull request not
# created) fails the run and, on the schedule, files the shared failure issue.
#
# Resolving a conflict pull request: merge `origin/gateway/integration` into
# the sync branch, resolve, push, get the review. Land it with a fast-forward
# push of the resolved merge commit to `gateway/integration`, not with the
# squash button: a squash drops the merge ancestry and the same hunks conflict
# again on the next run.
#
# Write scope: only `gateway/integration` and `sync/*` are ever pushed, and
# both push targets below are literal refs. The pushes use a one-hour
# installation token of the organisation's own 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. The conflict pull
# request is opened with FLAKE_UPDATE_TOKEN, the PAT that already opens the
# weekly flake.lock pull requests, because this repository keeps "Allow GitHub
# Actions to create and approve pull requests" switched off. GITHUB_TOKEN is
# therefore 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: ${{ inputs.source_ref || 'main' }}
        run: |
          set -euo pipefail
          if ! [[ "$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
          git diff --name-only --diff-filter=U > "$RUNNER_TEMP/conflicts.txt"
          git merge --abort
          if [[ ! -s "$RUNNER_TEMP/conflicts.txt" ]]; then
            echo "::error::git merge failed without reporting conflicting paths; this is not a conflict"
            exit 1
          fi
          echo "result=conflict" >> "$GITHUB_OUTPUT"

      - 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"

      - name: Open the conflict pull request
        if: steps.merge.outputs.result == 'conflict'
        env:
          GH_TOKEN: ${{ secrets.FLAKE_UPDATE_TOKEN }}
          SOURCE_REF: ${{ steps.merge.outputs.source_ref }}
          SOURCE_SHA: ${{ steps.merge.outputs.source_sha }}
          TARGET_SHA: ${{ steps.merge.outputs.target_sha }}
          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        run: |
          set -euo pipefail
          date_utc=$(date -u +%Y-%m-%d)
          sync_branch="sync/${SOURCE_REF//\//-}-${date_utc}"
          git push origin "refs/remotes/origin/${SOURCE_REF}:refs/heads/${sync_branch}"
          {
            echo "The scheduled merge of \`${SOURCE_REF}\` into \`${TARGET_BRANCH}\` stopped on conflicts and was aborted; \`${TARGET_BRANCH}\` is unchanged."
            echo
            echo "This branch is the un-merged \`${SOURCE_REF}\` head. Merge \`origin/${TARGET_BRANCH}\` into it, resolve the files below, push, and get the review. Land the resolved merge commit with a fast-forward push to \`${TARGET_BRANCH}\`; a squash merge drops the merge ancestry and the same hunks conflict again on the next run. Do not include any change that is not conflict resolution."
            echo
            echo "- Run: ${RUN_URL}"
            echo "- Source: \`${SOURCE_REF}\` at ${SOURCE_SHA}"
            echo "- Target: \`${TARGET_BRANCH}\` at ${TARGET_SHA}"
            echo
            echo "## Conflicting files"
            echo
            echo "Output of \`git diff --name-only --diff-filter=U\` captured before \`git merge --abort\`:"
            echo
            sed 's/^/- /' "$RUNNER_TEMP/conflicts.txt"
          } > "$RUNNER_TEMP/pr-body.md"
          title="sync: merge ${SOURCE_REF} ${date_utc} (conflicts)"
          existing=$(gh pr list --repo "$GITHUB_REPOSITORY" --base "$TARGET_BRANCH" --head "$sync_branch" --state open --json number --jq '.[0].number // empty')
          if [[ -n "$existing" ]]; then
            gh pr edit "$existing" --repo "$GITHUB_REPOSITORY" --title "$title" --body-file "$RUNNER_TEMP/pr-body.md"
            pr_url=$(gh pr view "$existing" --repo "$GITHUB_REPOSITORY" --json url --jq .url)
          else
            pr_url=$(gh pr create --repo "$GITHUB_REPOSITORY" --base "$TARGET_BRANCH" --head "$sync_branch" --title "$title" --body-file "$RUNNER_TEMP/pr-body.md")
          fi
          echo "Conflicts in \`${SOURCE_REF}\` -> \`${TARGET_BRANCH}\`; pull request: ${pr_url}" >> "$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 could not open the conflict pull request 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 }}