perf(comment-checker): add hard process reap and global semaphore to prevent CPU runaway

src/hooks/comment-checker/cli-runner.ts

@@ -4,6 +4,24 @@ import { existsSync } from "fs"
 import { runCommentChecker, getCommentCheckerPath, startBackgroundInit, type HookInput } from "./cli"
 
 let cliPathPromise: Promise<string | null> | null = null
+let isRunning = false
+
+async function withCommentCheckerLock<T>(
+  fn: () => Promise<T>,
+  fallback: T,
+  debugLog: (...args: unknown[]) => void,
+): Promise<T> {
+  if (isRunning) {
+    debugLog("comment-checker already running, skipping")
+    return fallback
+  }
+  isRunning = true
+  try {
+    return await fn()
+  } finally {
+    isRunning = false
+  }
+}
 
 export function initializeCommentCheckerCli(debugLog: (...args: unknown[]) => void): void {
   // Start background CLI initialization (may trigger lazy download)
@@ -30,32 +48,34 @@ export async function processWithCli(
   customPrompt: string | undefined,
   debugLog: (...args: unknown[]) => void,
 ): Promise<void> {
-  void input
-  debugLog("using CLI mode with path:", cliPath)
+  await withCommentCheckerLock(async () => {
+    void input
+    debugLog("using CLI mode with path:", cliPath)
 
-  const hookInput: HookInput = {
-    session_id: pendingCall.sessionID,
-    tool_name: pendingCall.tool.charAt(0).toUpperCase() + pendingCall.tool.slice(1),
-    transcript_path: "",
-    cwd: process.cwd(),
-    hook_event_name: "PostToolUse",
-    tool_input: {
-      file_path: pendingCall.filePath,
-      content: pendingCall.content,
-      old_string: pendingCall.oldString,
-      new_string: pendingCall.newString,
-      edits: pendingCall.edits,
-    },
-  }
+    const hookInput: HookInput = {
+      session_id: pendingCall.sessionID,
+      tool_name: pendingCall.tool.charAt(0).toUpperCase() + pendingCall.tool.slice(1),
+      transcript_path: "",
+      cwd: process.cwd(),
+      hook_event_name: "PostToolUse",
+      tool_input: {
+        file_path: pendingCall.filePath,
+        content: pendingCall.content,
+        old_string: pendingCall.oldString,
+        new_string: pendingCall.newString,
+        edits: pendingCall.edits,
+      },
+    }
 
-  const result = await runCommentChecker(hookInput, cliPath, customPrompt)
+    const result = await runCommentChecker(hookInput, cliPath, customPrompt)
 
-  if (result.hasComments && result.message) {
-    debugLog("CLI detected comments, appending message")
-    output.output += `\n\n${result.message}`
-  } else {
-    debugLog("CLI: no comments detected")
-  }
+    if (result.hasComments && result.message) {
+      debugLog("CLI detected comments, appending message")
+      output.output += `\n\n${result.message}`
+    } else {
+      debugLog("CLI: no comments detected")
+    }
+  }, undefined, debugLog)
 }
 
 export interface ApplyPatchEdit {
@@ -75,25 +95,27 @@ export async function processApplyPatchEditsWithCli(
   debugLog("processing apply_patch edits:", edits.length)
 
   for (const edit of edits) {
-    const hookInput: HookInput = {
-      session_id: sessionID,
-      tool_name: "Edit",
-      transcript_path: "",
-      cwd: process.cwd(),
-      hook_event_name: "PostToolUse",
-      tool_input: {
-        file_path: edit.filePath,
-        old_string: edit.before,
-        new_string: edit.after,
-      },
-    }
+    await withCommentCheckerLock(async () => {
+      const hookInput: HookInput = {
+        session_id: sessionID,
+        tool_name: "Edit",
+        transcript_path: "",
+        cwd: process.cwd(),
+        hook_event_name: "PostToolUse",
+        tool_input: {
+          file_path: edit.filePath,
+          old_string: edit.before,
+          new_string: edit.after,
+        },
+      }
 
-    const result = await runCommentChecker(hookInput, cliPath, customPrompt)
+      const result = await runCommentChecker(hookInput, cliPath, customPrompt)
 
-    if (result.hasComments && result.message) {
-      debugLog("CLI detected comments for apply_patch file:", edit.filePath)
-      output.output += `\n\n${result.message}`
-    }
+      if (result.hasComments && result.message) {
+        debugLog("CLI detected comments for apply_patch file:", edit.filePath)
+        output.output += `\n\n${result.message}`
+      }
+    }, undefined, debugLog)
   }
 }