Fix performance issues.

__tests__/sync.test.ts

@@ -10,6 +10,7 @@ import { describe, it, expect, beforeEach, afterEach } from 'vitest';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as os from 'os';
+import { execFileSync } from 'child_process';
 import CodeGraph from '../src/index';
 
 describe('Sync Module', () => {
@@ -150,4 +151,112 @@ describe('Sync Module', () => {
       });
     });
   });
+
+  describe('Git-based sync', () => {
+    let testDir: string;
+    let cg: CodeGraph;
+
+    function git(...args: string[]) {
+      execFileSync('git', args, { cwd: testDir, stdio: 'pipe' });
+    }
+
+    beforeEach(async () => {
+      testDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codegraph-git-sync-'));
+
+      // Initialize a git repo with an initial commit
+      git('init');
+      git('config', 'user.email', 'test@test.com');
+      git('config', 'user.name', 'Test');
+
+      const srcDir = path.join(testDir, 'src');
+      fs.mkdirSync(srcDir);
+      fs.writeFileSync(
+        path.join(srcDir, 'index.ts'),
+        `export function hello() { return 'world'; }`
+      );
+
+      git('add', '-A');
+      git('commit', '-m', 'initial');
+
+      // Initialize CodeGraph and index
+      cg = CodeGraph.initSync(testDir, {
+        config: {
+          include: ['**/*.ts'],
+          exclude: [],
+        },
+      });
+      await cg.indexAll();
+    });
+
+    afterEach(() => {
+      if (cg) {
+        cg.destroy();
+      }
+      if (fs.existsSync(testDir)) {
+        fs.rmSync(testDir, { recursive: true, force: true });
+      }
+    });
+
+    it('should detect modified files via git', async () => {
+      fs.writeFileSync(
+        path.join(testDir, 'src', 'index.ts'),
+        `export function hello() { return 'modified'; }`
+      );
+
+      const result = await cg.sync();
+
+      expect(result.filesModified).toBe(1);
+      expect(result.changedFilePaths).toContain('src/index.ts');
+    });
+
+    it('should detect new untracked files via git', async () => {
+      fs.writeFileSync(
+        path.join(testDir, 'src', 'new.ts'),
+        `export function newFunc() { return 42; }`
+      );
+
+      const result = await cg.sync();
+
+      expect(result.filesAdded).toBe(1);
+      expect(result.changedFilePaths).toContain('src/new.ts');
+
+      // Verify the function was indexed
+      const nodes = cg.searchNodes('newFunc');
+      expect(nodes.length).toBeGreaterThan(0);
+    });
+
+    it('should detect deleted files via git', async () => {
+      fs.unlinkSync(path.join(testDir, 'src', 'index.ts'));
+
+      const result = await cg.sync();
+
+      expect(result.filesRemoved).toBe(1);
+
+      // Verify function is gone
+      const nodes = cg.searchNodes('hello');
+      expect(nodes.length).toBe(0);
+    });
+
+    it('should skip files not matching config', async () => {
+      // Create a .js file which doesn't match **/*.ts
+      fs.writeFileSync(
+        path.join(testDir, 'src', 'ignored.js'),
+        `function ignored() {}`
+      );
+
+      const result = await cg.sync();
+
+      expect(result.filesAdded).toBe(0);
+      expect(result.filesModified).toBe(0);
+    });
+
+    it('should report no changes on clean working tree', async () => {
+      const result = await cg.sync();
+
+      expect(result.filesAdded).toBe(0);
+      expect(result.filesModified).toBe(0);
+      expect(result.filesRemoved).toBe(0);
+      expect(result.changedFilePaths).toBeUndefined();
+    });
+  });
 });