def main()

in dev/bk-merge-pr3.py [0:0]


def main():
    global original_head

    if not GITHUB_OAUTH_KEY:
        print("OAuth key is needed for merging bookkeeper pull requests.")
        print("If environment variable 'GITHUB_OAUTH_KEY' is not defined,")
        print("then requests will be unauthenticated.")
        print("You can create an OAuth key at https://github.com/settings/tokens")
        print("and set it to the environment variable 'GITHUB_OAUTH_KEY'.")
        print("(This token only needs the 'public_repo' scope permissions)")
        exit(-1)

    # 0. get the current state so we can go back
    original_head = get_current_branch()

    # 1. retrieve milestones, labels, branches
    milestones = get_milestones()
    labels = get_all_labels()
    branches = get_json("%s/branches" % GITHUB_API_BASE)
    branch_names = list(filter(lambda x: x.startswith(RELEASE_BRANCH_PREFIX), [x['name'] for x in branches]))
    # Assumes branch names can be sorted lexicographically
    latest_branch = sorted(branch_names, reverse=True)[0]

    # 2. retrieve the details for a given pull request
    pr_num = input("Which pull request would you like to merge? (e.g. 34): ")
    pr = get_json("%s/pulls/%s" % (GITHUB_API_BASE, pr_num))
    pr_events = get_json("%s/issues/%s/events" % (GITHUB_API_BASE, pr_num))
    pr_reviewers = get_reviewers(pr_num)
    check_ci_status(pr)

    url = pr["url"]

    # 3. repair the title for commit message
    pr_title = pr["title"]
    commit_title = input("Commit title [%s]: " % pr_title)
    if commit_title == "":
        commit_title = pr_title

    # Decide whether to use the modified title or not
    modified_title, github_issue_ids = standardize_issue_ref(commit_title)
    if modified_title != commit_title:
        print("I've re-written the title as follows to match the standard format:")
        print("Original: %s" % commit_title)
        print("Modified: %s" % modified_title)
        result = input("Would you like to use the modified title? (y/n): ")
        if result.lower() == "y":
            commit_title = modified_title
            print("Using modified title:")
        else:
            print("Using original title:")
        print(commit_title)

    body = pr["body"]
    modified_body = ""
    for line in body.split('\n'):
        if line.startswith('>'):
            continue
        modified_body = modified_body + line + "\n"
    modified_body = modified_body[:-1]
    if modified_body != body:
        print("I've re-written the body as follows to match the standard formats:")
        print("Original: ")
        print(body)
        print("Modified: ")
        print(modified_body)
        result = input("Would you like to use the modified body? (y/n): ")
        if result.lower() == "y":
            body = modified_body
            print("Using modified body.")
        else:
            print("Using original body.")

    target_ref = pr["base"]["ref"]
    user_login = pr["user"]["login"]
    base_ref = pr["head"]["ref"]
    pr_repo_desc = "%s/%s" % (user_login, base_ref)

    # append pr num to the github issues - we need to attach label and milestone to them
    github_issue_ids.append(pr_num)

    #
    # 4. attach milestone, area, type and release to github issues
    #

    # get issue labels
    issue_labels = get_github_issue_labels(pr_num)
    # ask for fix milestone, area and type
    fix_milestone, fix_milestone_number, fix_areas, fix_types = \
        ask_updates_for_github_issues(milestones, labels, issue_labels, target_ref == "master")
    # update issues with fix milestone, are and type
    other_labels = list(filter(lambda x: not x.startswith("area"), issue_labels))
    all_issue_labels = update_github_issues( \
        github_issue_ids, \
        fix_milestone_number, \
        fix_milestone, \
        fix_areas, \
        fix_types, \
        other_labels)
    # add the pr author to the assignees
    add_assignees_to_github_issues(github_issue_ids, [ user_login ])

    if target_ref != "master":
        branch_version = target_ref.split('-')[1]
        # add releases
        fix_releases = ask_release_for_github_issues(branch_version, labels)
        if len(fix_releases) > 0:
            all_issue_labels = add_release_to_github_issues(github_issue_ids, all_issue_labels, fix_releases[0])

    #
    # 5. Process the merge
    #

    # Merged pull requests don't appear as merged in the GitHub API;
    # Instead, they're closed by asfgit.
    merge_commits = \
        [e for e in pr_events if e["actor"]["login"] == "asfgit" and e["event"] == "closed"]

    if merge_commits:
        merge_hash = merge_commits[0]["commit_id"]
        message = get_json("%s/commits/%s" % (GITHUB_API_BASE, merge_hash))["commit"]["message"]

        print("Pull request %s has already been merged, assuming you want to backport" % pr_num)
        commit_is_downloaded = run_cmd(['git', 'rev-parse', '--quiet', '--verify',
                                    "%s^{commit}" % merge_hash]).strip() != ""
        if not commit_is_downloaded:
            fail("Couldn't find any merge commit for #%s, you may need to update HEAD." % pr_num)

        print("Found commit %s:\n%s" % (merge_hash, message))
        
        cherry_pick(pr_num, merge_hash, ask_for_branch(latest_branch))
        sys.exit(0)

    if not bool(pr["mergeable"]):
        msg = "Pull request %s is not mergeable in its current form.\n" % pr_num + \
            "You may need to rebase the PR."
        fail(msg)

    print("\n=== Pull Request #%s ===" % pr_num)
    print("PR title\t%s\nCommit title\t%s\nSource\t\t%s\nTarget\t\t%s\nURL\t\t%s" % (
        pr_title, commit_title, pr_repo_desc, target_ref, url))
    continue_maybe("Proceed with merging pull request #%s?" % pr_num)

    merged_refs = [target_ref]
    # proceed with the merge
    merge_hash, merge_commit_log = merge_pr(pr_num, target_ref, commit_title, body, pr_reviewers, pr_repo_desc)

    # once the pr is merged, refresh the local repo
    run_cmd("git fetch %s" % PR_REMOTE_NAME)

    pick_prompt = "Would you like to pick %s into another branch?" % merge_hash
    while input("\n%s (y/n): " % pick_prompt).lower() == "y":
        pick_ref = ask_for_branch(latest_branch) 
        branch_version = pick_ref.split('-')[1]
        # add releases
        fix_releases = ask_release_for_github_issues(branch_version, labels)
        if len(fix_releases) > 0:
            all_issue_labels = add_release_to_github_issues(github_issue_ids, all_issue_labels, fix_releases[0])
        merged_refs = merged_refs + [cherry_pick(pr_num, merge_hash, pick_ref)]