⚡ Bolt: Parallelize PR inspections in merge scheduler

.jules/bolt.md

@@ -13,3 +13,6 @@
 ## 2026-06-14 - Deferring Pathlib Operations in Hot Paths
 **Learning:** In highly repetitive loops like file scanners (e.g., iterating through thousands of safe files), preemptively calculating `Path.relative_to()` and sanitizing strings adds significant cumulative overhead. Pathlib operations internally parse paths, check parts, and construct new objects, which is extremely expensive when executed on a per-file basis unconditionally.
 **Action:** Always defer expensive path computations (like converting paths to relative or string sanitization) until *after* the fast-path condition (like a regex match) triggers. This drastically cuts down on unnecessary string operations for clean files.
+## 2024-06-16 - Parallelize Subprocess CLI Calls
+**Learning:** Sequential, synchronous execution of `subprocess.run` (like calling the GitHub CLI) across multiple items (like PRs) is a significant I/O bottleneck.
+**Action:** Use `concurrent.futures.ThreadPoolExecutor` with `functools.partial` and `executor.map` to safely parallelize I/O-bound subprocess executions, significantly reducing overall script runtime.

scripts/ci/pr_review_merge_scheduler.py

@@ -6,6 +6,8 @@
 import os
 import subprocess
 import sys
+import concurrent.futures
+from functools import partial
 from dataclasses import dataclass
 from typing import Any
 
@@ -330,17 +332,18 @@ def main(argv: list[str]) -> int:
     if not args.repo:
         raise SystemExit("--repo is required")
     prs = fetch_open_prs(args.repo, args.max_prs)
-    decisions = [
-        inspect_pr(
-            args.repo,
-            pr,
-            dry_run=args.dry_run,
-            trigger_reviews=args.trigger_reviews,
-            enable_auto_merge_flag=args.enable_auto_merge,
-            workflow=args.review_workflow,
-        )
-        for pr in prs
-    ]
+
+    inspect_func = partial(
+        inspect_pr,
+        args.repo,
+        dry_run=args.dry_run,
+        trigger_reviews=args.trigger_reviews,
+        enable_auto_merge_flag=args.enable_auto_merge,
+        workflow=args.review_workflow,
+    )
+    with concurrent.futures.ThreadPoolExecutor() as executor:
+        decisions = list(executor.map(inspect_func, prs))
+
     print_summary(decisions, dry_run=args.dry_run)
     return 0