[llvm] [Utils] Add new merge-release-pr.py script. (PR #101630)

[Aiden Grossman via llvm-commits]

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+#!/usr/bin/env python3
+# ===-- merge-release-pr.py  ------------------------------------------------===#
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# ===------------------------------------------------------------------------===#
+#
+# Helper script that will merge a Pull Request into a release branch. It will first
+# do some validations of the PR then rebase and finally push the changes to the
+# release branch.
+#
+# Usage: merge-release-pr.py <PR id>
+# By default it will push to the 'upstream' origin, but you can pass
+# --upstream-origin/-o <origin> if you want to change it.
+#
+# If you want to skip a specific validation, like the status checks you can
+# pass -s status_checks, this argument can be passed multiple times.
+#
+import argparse
+import json
+import subprocess
+import sys
+import time
+from typing import List
+
+
+class PRMerger:
+    def __init__(self, args):
+        self.pr = args.pr
+        self.args = args
+
+    def run_gh(self, gh_cmd: str, args: List[str]) -> str:
+        cmd = ["gh", gh_cmd, "-Rllvm/llvm-project"] + args
+        p = subprocess.run(cmd, capture_output=True)
+        if p.returncode != 0:
+            print(p.stderr)
+            raise RuntimeError("Failed to run gh")
+        return p.stdout
+
+    # Validate the state of the PR, this means making sure that it is
+    # OPEN and not already merged or closed.
+    def validate_state(self, data):
+        state = data["state"]
+        if state != "OPEN":
+            return False, f"state is {state.lower()}, not open"
+        return True
+
+    # Validate that the PR is targetting a release/ branch. We could
+    # validate the exact branch here, but I am not sure how to figure
+    # out what we want except an argument and that might be a bit to
+    # to much overhead.
+    def validate_target_branch(self, data):
+        baseRefName: str = data["baseRefName"]
+        if not baseRefName.startswith("release/"):
+            return False, f"target branch is {baseRefName}, not a release branch"
+        return True
+
+    # Validate the approval decision. This checks that the PR has been
+    # approved.
+    def validate_approval(self, data):
+        if data["reviewDecision"] != "APPROVED":
+            return False, "PR is not approved"
+        return True
+
+    # Check that all the actions / status checks succeeded. Will also
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boomanaiden154 wrote:

Docstring here.

https://github.com/llvm/llvm-project/pull/101630