GitHub Verify a Branch and Merge It

arazzo: 1.0.1
info:
  title: GitHub Verify a Branch and Merge It
  summary: Confirm a head branch exists, then merge it into a base branch.
  description: >-
    A server-side branch integration pattern that does not require a pull
    request. The workflow verifies the head branch exists and reads its tip
    commit, then performs a merge of that head branch into the base branch.
    Every step spells out its request inline so the flow can be read and
    executed without opening the underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: githubRepoBranchesApi
  url: ../openapi/github-repo-branches-api-openapi.yml
  type: openapi
- name: githubReposApi
  url: ../openapi/github-repos-api-openapi.yml
  type: openapi
workflows:
- workflowId: verify-and-merge-branch
  summary: Verify a head branch exists then merge it into a base branch.
  description: >-
    Reads the head branch to confirm it exists and then merges it into the base
    branch with a custom commit message.
  inputs:
    type: object
    required:
    - githubToken
    - owner
    - repo
    - headBranch
    - baseBranch
    properties:
      githubToken:
        type: string
        description: A GitHub token with repo scope, passed as a Bearer credential.
      owner:
        type: string
        description: The account owner of the repository.
      repo:
        type: string
        description: The name of the repository.
      headBranch:
        type: string
        description: The branch to merge in (the head of the merge).
      baseBranch:
        type: string
        description: The branch to receive the merge (the base of the merge).
      commitMessage:
        type: string
        description: The commit message to use for the merge commit.
  steps:
  - stepId: verifyHeadBranch
    description: >-
      Read the head branch to confirm it exists before attempting the merge.
    operationId: getBranch
    parameters:
    - name: Authorization
      in: header
      value: Bearer $inputs.githubToken
    - name: owner
      in: path
      value: $inputs.owner
    - name: repo
      in: path
      value: $inputs.repo
    - name: branch
      in: path
      value: $inputs.headBranch
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      headSha: $response.body#/commit/sha
  - stepId: mergeIntoBase
    description: >-
      Merge the verified head branch into the base branch with the supplied
      commit message.
    operationId: mergeBranch
    parameters:
    - name: Authorization
      in: header
      value: Bearer $inputs.githubToken
    - name: owner
      in: path
      value: $inputs.owner
    - name: repo
      in: path
      value: $inputs.repo
    requestBody:
      contentType: application/json
      payload:
        base: $inputs.baseBranch
        head: $inputs.headBranch
        commit_message: $inputs.commitMessage
    successCriteria:
    - condition: $statusCode == 201
    outputs:
      mergeSha: $response.body#/sha
      mergeUrl: $response.body#/html_url
  outputs:
    headSha: $steps.verifyHeadBranch.outputs.headSha
    mergeSha: $steps.mergeIntoBase.outputs.mergeSha
    mergeUrl: $steps.mergeIntoBase.outputs.mergeUrl