git-batch-merge.yaml

apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: git-batch-merge
  labels:
    app.kubernetes.io/version: "0.1"
  annotations:
    tekton.dev/pipelines.minVersion: "0.12.1"
    tekton.dev/tags: git
    tekton.dev/displayName: "git batch merge"
spec:
  description: >-
    This task takes a set of refspecs, fetches them and performs git operations
    (cherry-pick or merge) to apply them in order on the given base revision (default master).

    The resulting commit SHA will not match across taskruns, but the git tree SHA should
    match. This can be useful for batch testing changes, for example, when you want to
    batch up your PRs into a single merge by taking the HEAD of the branch you want to merge
    to, and adding all the PRs to it. This concept is used in tools such as Tide to
    batch test PR’s, and Zuul CI Gating, to perform speculative execution of
    PR’s/change requests individually

  workspaces:
    - name: output
      description: The git repo will be cloned onto the volume backing this workspace
  params:
    - name: url
      description: git url to clone
      type: string
    - name: revision
      description: base git revision to checkout (branch, tag, sha, ref…)
      type: string
      default: master
    - name: refspec
      description: base git refspec to fetch before checking out revision
      type: string
      default: "refs/heads/master:refs/heads/master"
    - name: batchedRefs
      description: git refs to fetch and batch on top of revision using the given mode (must be a valid refname, no commit SHA's)
      type: string
    - name: gitUserName
      description: git user name to use for creating the batched commit (First Last)
      type: string
      default: GitBatch Task
    - name: gitUserEmail
      description: git user email to use for creating the batched commit (First.Last@domain.com)
      type: string
      default: GitBatch.Task@tekton.dev
    - name: mode
      description: git operation to perform while batching (choose from merge, cherry-pick)
      type: string
      default: merge
    - name: submodules
      description: defines if the resource should initialize and fetch the submodules
      type: string
      default: "true"
    - name: depth
      description: performs a shallow clone where only the most recent commit(s) will be fetched
      type: string
      default: "1"
    - name: sslVerify
      description: defines if http.sslVerify should be set to true or false in the global git config
      type: string
      default: "true"
    - name: subdirectory
      description: subdirectory inside the "output" workspace to clone the git repo into
      type: string
      default: "src"
    - name: deleteExisting
      description: clean out the contents of the repo's destination directory (if it already exists) before trying to clone the repo there
      type: string
      default: "false"
  results:
    - name: commit
      description: The final commit SHA that was obtained after batching all provided refs onto revision
    - name: tree
      description: The git tree SHA that was obtained after batching all provided refs onto revision.
  steps:
    - name: clone
      image: gcr.io/tekton-releases/github.com/tektoncd/pipeline/cmd/git-init:v0.14.2
      script: |
        CHECKOUT_DIR="$(workspaces.output.path)/$(params.subdirectory)"

        cleandir() {
          # Delete any existing contents of the repo directory if it exists.
          #
          # We don't just "rm -rf $CHECKOUT_DIR" because $CHECKOUT_DIR might be "/"
          # or the root of a mounted volume.
          if [[ -d "$CHECKOUT_DIR" ]] ; then
            # Delete non-hidden files and directories
            rm -rf "$CHECKOUT_DIR"/*
            # Delete files and directories starting with . but excluding ..
            rm -rf "$CHECKOUT_DIR"/.[!.]*
            # Delete files and directories starting with .. plus any other character
            rm -rf "$CHECKOUT_DIR"/..?*
          fi
        }

        if [[ "$(params.deleteExisting)" == "true" ]] ; then
          cleandir
        fi

        p="$(params.batchedRefs)"
        refs="$(params.refspec)"
        for ref in $p; do
          refs="$refs $ref:refs/batch/$ref"
        done

        /ko-app/git-init \
          -url "$(params.url)" \
          -revision "$(params.revision)" \
          -refspec "$refs" \
          -path "$CHECKOUT_DIR" \
          -sslVerify="$(params.sslVerify)" \
          -submodules="$(params.submodules)" \
          -depth "$(params.depth)"

        git -C $CHECKOUT_DIR config user.name "$(params.gitUserName)"
        git -C $CHECKOUT_DIR config user.email "$(params.gitUserEmail)"

        mode="$(params.mode)"
        if [[ $mode == "merge" ]]; then
          for ref in $p; do
             git -C $CHECKOUT_DIR merge --quiet --allow-unrelated-histories refs/batch/$ref
          done
        elif [[ $mode == "cherry-pick" ]]; then
          for ref in $p; do
             git -C $CHECKOUT_DIR cherry-pick --allow-empty --keep-redundant-commits refs/batch/$ref
          done
        else
            echo "unsupported mode $mode"
            exit 1
        fi

        RESULT_SHA="$(git -C $CHECKOUT_DIR rev-parse HEAD)"
        TREE_SHA="$(git -C $CHECKOUT_DIR rev-parse HEAD^{tree})"
        # Make sure we don't add a trailing newline to the result!
        echo -n "$(echo $RESULT_SHA | tr -d '\n')" > $(results.commit.path)
        echo -n "$(echo $TREE_SHA | tr -d '\n')" > $(results.tree.path)