Add a script for bulk merging PRs

When modulesyncing, often CI is overloaded. This script makes it easy to
automatically merge PRs when CI is green and there's approval. This
allows reviewers to approve and later on automatically merge when CI is
done.

bin/merge-prs

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+import os
+from argparse import ArgumentParser
+
+from github import Github
+
+
+def verify_pull_request(title, pull_request, required_status, merge):
+    description = f"{title} ({pull_request.title})"
+
+    if pull_request.merged:
+        print(f"{description} is merged")
+        return
+
+    if not pull_request.state == 'open':
+        print(f"{description} is {pull_request.state}")
+        return
+
+    if not pull_request.mergeable:
+        print(f"{description} is not mergeable")
+        return
+
+    reviews = pull_request.get_reviews()
+    if not [review for review in reviews if review.state != 'PENDING']:
+        print(f"{description} has no reviews")
+        return
+
+    commit = list(pull_request.get_commits())[-1]
+    combined_status = commit.get_combined_status()
+    if combined_status.state != 'success':
+        print(f"{description} CI status is {combined_status.state}")
+        return
+
+    if required_status:
+        # Travis can not a required status on GH because that blocks other workflows
+        if not any(status.context == required_status for status in combined_status.statuses):
+            print(f"{description} does not have a status from {required_status}")
+            return
+
+    approved = all(review.state in ('APPROVED', 'PENDING') for review in reviews)
+    if not approved:
+        print(f"{description} is not approved")
+        return
+
+    if merge:
+        print(f"Merging {description}")
+        pull_request.merge()
+    else:
+        print(f"{description} can be merged")
+
+
+def main():
+    parser = ArgumentParser()
+    parser.add_argument('pull_request', nargs='+', help="Pass in PRs as user/repo#pr")
+    parser.add_argument('--required-status', help='Require this status context',
+                        default='continuous-integration/travis-ci/pr')
+    parser.add_argument('--merge', help='Actually merge', action='store_true')
+
+    args = parser.parse_args()
+
+    github = Github(os.environ.get('GITHUB_TOKEN'))
+
+    for pull_request in args.pull_request:
+        name, number = pull_request.split('#', 1)
+        repo = github.get_repo(name)
+        pull = repo.get_pull(int(number))
+        verify_pull_request(pull_request, pull, args.required_status, args.merge)
+
+
+if __name__ == '__main__':
+    main()