Fix cherry-pick workflow (#2727)

Summary:
Pull Request resolved: #2727

imported-using-ghimport

Test Plan: Imported from OSS

Reviewed By: mcr229

Differential Revision: D55450296

Pulled By: guangy10

fbshipit-source-id: 8037d1e06f14f1c7ace1fbe7aa150f1c8b4c697f

Author: guangy10

.github/scripts/cherry_pick.py

@@ -0,0 +1,228 @@
+#!/usr/bin/env python3
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+import json
+import os
+import re
+from typing import Any, Optional
+
+from urllib.error import HTTPError
+
+from github_utils import gh_fetch_url, gh_post_pr_comment
+
+from gitutils import get_git_remote_name, get_git_repo_dir, GitRepo
+from trymerge import get_pr_commit_sha, GitHubPR
+
+
+# This is only a suggestion for now, not a strict requirement
+REQUIRES_ISSUE = {
+    "regression",
+    "critical",
+    "fixnewfeature",
+}
+
+
+def parse_args() -> Any:
+    from argparse import ArgumentParser
+
+    parser = ArgumentParser("cherry pick a landed PR onto a release branch")
+    parser.add_argument(
+        "--onto-branch", type=str, required=True, help="the target release branch"
+    )
+    parser.add_argument(
+        "--github-actor", type=str, required=True, help="all the world’s a stage"
+    )
+    parser.add_argument(
+        "--classification",
+        choices=["regression", "critical", "fixnewfeature", "docs", "release"],
+        required=True,
+        help="the cherry pick category",
+    )
+    parser.add_argument("pr_num", type=int)
+    parser.add_argument(
+        "--fixes",
+        type=str,
+        default="",
+        help="the GitHub issue that the cherry pick fixes",
+    )
+    parser.add_argument("--dry-run", action="store_true")
+
+    return parser.parse_args()
+
+
+def get_merge_commit_sha(repo: GitRepo, pr: GitHubPR) -> Optional[str]:
+    """
+    Return the merge commit SHA iff the PR has been merged. For simplicity, we
+    will only cherry pick PRs that have been merged into main
+    """
+    commit_sha = get_pr_commit_sha(repo, pr)
+    return commit_sha if pr.is_closed() else None
+
+
+def cherry_pick(
+    github_actor: str,
+    repo: GitRepo,
+    pr: GitHubPR,
+    commit_sha: str,
+    onto_branch: str,
+    classification: str,
+    fixes: str,
+    dry_run: bool = False,
+) -> None:
+    """
+    Create a local branch to cherry pick the commit and submit it as a pull request
+    """
+    current_branch = repo.current_branch()
+    cherry_pick_branch = create_cherry_pick_branch(
+        github_actor, repo, pr, commit_sha, onto_branch
+    )
+
+    try:
+        if not dry_run:
+            org, project = repo.gh_owner_and_name()
+            cherry_pick_pr = submit_pr(repo, pr, cherry_pick_branch, onto_branch)
+
+            msg = f"The cherry pick PR is at {cherry_pick_pr}"
+            if fixes:
+                msg += f" and it is linked with issue {fixes}"
+            elif classification in REQUIRES_ISSUE:
+                msg += f" and it is recommended to link a {classification} cherry pick PR with an issue"
+
+            post_comment(org, project, pr.pr_num, msg)
+
+    finally:
+        if current_branch:
+            repo.checkout(branch=current_branch)
+
+
+def create_cherry_pick_branch(
+    github_actor: str, repo: GitRepo, pr: GitHubPR, commit_sha: str, onto_branch: str
+) -> str:
+    """
+    Create a local branch and cherry pick the commit. Return the name of the local
+    cherry picking branch.
+    """
+    repo.checkout(branch=onto_branch)
+    repo._run_git("submodule", "update", "--init", "--recursive")
+
+    # Remove all special characters if we want to include the actor in the branch name
+    github_actor = re.sub("[^0-9a-zA-Z]+", "_", github_actor)
+
+    cherry_pick_branch = f"cherry-pick-{pr.pr_num}-by-{github_actor}"
+    repo.create_branch_and_checkout(branch=cherry_pick_branch)
+
+    # We might want to support ghstack later
+    repo._run_git("cherry-pick", "-x", "-X", "theirs", commit_sha)
+    repo.push(branch=cherry_pick_branch, dry_run=False)
+
+    return cherry_pick_branch
+
+
+def submit_pr(
+    repo: GitRepo,
+    pr: GitHubPR,
+    cherry_pick_branch: str,
+    onto_branch: str,
+) -> str:
+    """
+    Submit the cherry pick PR and return the link to the PR
+    """
+    org, project = repo.gh_owner_and_name()
+
+    default_msg = f"Cherry pick #{pr.pr_num} onto {onto_branch} branch"
+    title = pr.info.get("title", default_msg)
+    body = pr.info.get("body", default_msg)
+
+    try:
+        response = gh_fetch_url(
+            f"https://api.github.com/repos/{org}/{project}/pulls",
+            method="POST",
+            data={
+                "title": title,
+                "body": body,
+                "head": cherry_pick_branch,
+                "base": onto_branch,
+            },
+            headers={"Accept": "application/vnd.github.v3+json"},
+            reader=json.load,
+        )
+
+        cherry_pick_pr = response.get("html_url", "")
+        if not cherry_pick_pr:
+            raise RuntimeError(
+                f"Fail to find the cherry pick PR: {json.dumps(response)}"
+            )
+
+        return str(cherry_pick_pr)
+
+    except HTTPError as error:
+        msg = f"Fail to submit the cherry pick PR: {error}"
+        raise RuntimeError(msg) from error
+
+
+def post_comment(org: str, project: str, pr_num: int, msg: str) -> None:
+    """
+    Post a comment on the PR itself to point to the cherry picking PR when success
+    or print the error when failure
+    """
+    internal_debugging = ""
+
+    run_url = os.getenv("GH_RUN_URL")
+    # Post a comment to tell folks that the PR is being cherry picked
+    if run_url is not None:
+        internal_debugging = "\n".join(
+            line
+            for line in (
+                "<details><summary>Details for Dev Infra team</summary>",
+                f'Raised by <a href="{run_url}">workflow job</a>\n',
+                "</details>",
+            )
+            if line
+        )
+
+    comment = "\n".join(
+        (f"### Cherry picking #{pr_num}", f"{msg}", "", f"{internal_debugging}")
+    )
+    gh_post_pr_comment(org, project, pr_num, comment)
+
+
+def main() -> None:
+    args = parse_args()
+    pr_num = args.pr_num
+
+    repo = GitRepo(get_git_repo_dir(), get_git_remote_name())
+    org, project = repo.gh_owner_and_name()
+
+    pr = GitHubPR(org, project, pr_num)
+
+    try:
+        commit_sha = get_merge_commit_sha(repo, pr)
+        if not commit_sha:
+            raise RuntimeError(
+                f"Refuse to cherry pick #{pr_num} because it hasn't been merged yet"
+            )
+
+        cherry_pick(
+            args.github_actor,
+            repo,
+            pr,
+            commit_sha,
+            args.onto_branch,
+            args.classification,
+            args.fixes,
+            args.dry_run,
+        )
+
+    except RuntimeError as error:
+        if not args.dry_run:
+            post_comment(org, project, pr_num, str(error))
+        else:
+            raise error
+
+
+if __name__ == "__main__":
+    main()