⚡ Bolt: Remove synchronous I/O operations from core logic

.jules/bolt.md

@@ -70,3 +70,6 @@
 ## 2023-10-27 - O(N) Re-renders in List Components
 **Learning:** React list components mapped from arrays (e.g. `sessions.map(...)`) will experience severe O(N) re-renders when a single element changes state if the evaluation is done inline inside the map without memoization. Passing the active check (e.g., `isActive={activeSessionId === s.id}`) down to a `React.memo` wrapper component is necessary to convert this into an O(1) re-render (only the two affected components will update).
 **Action:** When creating high-frequency updating list elements with individual active states in React, extract the items into `React.memo` components and pass simple boolean flags to prevent massive VDOM updates.
+## 2024-05-24 - [Remove Synchronous File Operations]
+**Learning:** Checking for file existence using `fs.existsSync` introduces blocking I/O on the Node.js event loop, creating micro-stutters and reducing application concurrency.
+**Action:** Always prefer asynchronous file access (e.g., `fs.promises.readFile` or `fs.promises.access`) enclosed in a `try...catch` block. This approach avoids blocking and eliminates Time-of-Check to Time-of-Use (TOCTOU) race conditions.

packages/core/src/agent.ts

@@ -1,7 +1,6 @@
 import Anthropic from '@anthropic-ai/sdk';
 import type { MessageParam, Tool, ToolUseBlock, TextBlock, ContentBlock } from '@anthropic-ai/sdk/resources/messages';
 import fetch from 'node-fetch';
-import { existsSync, readFileSync } from 'fs';
 import { readFile } from 'fs/promises';
 import { join } from 'path';
 import { homedir } from 'os';
@@ -759,12 +758,10 @@ export class EnhancedAgent extends EventEmitter {
       } else {
         // Fallback: read .xibecode/memory.md directly (cheap single read)
         const fallbackMd = join(process.cwd(), '.xibecode', 'memory.md');
-        if (existsSync(fallbackMd)) {
-          try {
-            const content = await readFile(fallbackMd, 'utf-8');
-            this.autoMemoryMarkdownSection = `\n\n## Project Memory\n\n${content.trim()}`;
-          } catch { /* ignore */ }
-        }
+        try {
+          const content = await readFile(fallbackMd, 'utf-8');
+          this.autoMemoryMarkdownSection = `\n\n## Project Memory\n\n${content.trim()}`;
+        } catch { /* ignore if not exist */ }
       }
 
       if (newMem.trim() && !this.autoMemoryMarkdownSection.includes(newMem.trim())) {

packages/core/src/code-graph.ts

@@ -24,7 +24,15 @@ export class CodeGraph {
         if (this.isInitialized) return;
 
         const tsConfigPath = path.join(this.workingDir, 'tsconfig.json');
-        if (fs.existsSync(tsConfigPath)) {
+        let hasTsConfig = false;
+        try {
+            await fs.promises.access(tsConfigPath);
+            hasTsConfig = true;
+        } catch {
+            hasTsConfig = false;
+        }
+
+        if (hasTsConfig) {
             this.project = new Project({
                 tsConfigFilePath: tsConfigPath,
                 skipAddingFilesFromTsConfig: false,

packages/core/src/memory.ts

@@ -1,5 +1,4 @@
 import * as fs from 'fs/promises';
-import { existsSync } from 'fs';
 import * as path from 'path';
 import { createHash } from 'crypto';
 import { MemoryPromotions } from './memory-promotions.js';
@@ -36,13 +35,15 @@ export class NeuralMemory {
 
         try {
             const xibeDir = path.dirname(this.memoryFile);
-            if (!existsSync(xibeDir)) {
-                await fs.mkdir(xibeDir, { recursive: true });
-            }
+            await fs.mkdir(xibeDir, { recursive: true });
 
-            if (existsSync(this.memoryFile)) {
+            try {
                 const content = await fs.readFile(this.memoryFile, 'utf-8');
                 this.memory = JSON.parse(content);
+            } catch (readError: any) {
+                if (readError.code !== 'ENOENT') {
+                    throw readError;
+                }
             }
             this.initialized = true;
         } catch (error) {

packages/core/src/permission-store.ts

@@ -1,5 +1,4 @@
 import * as fs from 'fs/promises';
-import { existsSync } from 'fs';
 import * as path from 'path';
 import type { PermissionMode } from './permissions.js';
 
@@ -18,10 +17,6 @@ export class PermissionStore {
   }
 
   async load(): Promise<PersistedPermissionState | null> {
-    if (!existsSync(this.storePath)) {
-      return null;
-    }
-
     try {
       const raw = await fs.readFile(this.storePath, 'utf8');
       const parsed = JSON.parse(raw) as PersistedPermissionState;

packages/core/src/utils/auto-memory.ts

@@ -3,8 +3,7 @@
  * Keyword relevance scoring; optional env to disable.
  */
 
-import { existsSync } from 'fs';
-import { readFile, readdir } from 'fs/promises';
+import { readFile, readdir, access } from 'fs/promises';
 import { homedir } from 'os';
 import { join } from 'path';
 
@@ -75,9 +74,6 @@ async function loadMemoryFile(
   type: LoadedMemory['type'],
 ): Promise<LoadedMemory | null> {
   try {
-    if (!existsSync(filePath)) {
-      return null;
-    }
     const content = await readFile(filePath, 'utf-8');
     return {
       path: filePath,
@@ -117,11 +113,9 @@ async function loadProjectMemories(cwd: string): Promise<LoadedMemory[]> {
   }
 
   const autoDir = join(cwd, '.xibecode', 'memories');
-  if (!existsSync(autoDir)) {
-    return memories;
-  }
 
   try {
+    await access(autoDir);
     const names = await readdir(autoDir, { withFileTypes: true });
     const mdFiles = names.filter((d) => d.isFile() && d.name.endsWith('.md')).map((d) => join(autoDir, d.name));
     for (const fp of mdFiles.slice(0, MAX_AUTO_LOAD_MEMORIES)) {