fix(repos): 修复在全新的工作目录中，检出指定commit时，找不到commit.

src/repos/repos.service.ts

@@ -26,8 +26,14 @@ export class ReposService {
     );
   }
 
+  async lockWorkspace(workspaceRoot: string) {
+    // TODO:  获取锁，失败抛错。
+  }
+
   async getGit(project: Project) {
     const workspaceRoot = this.getWorkspaceRoot(project);
+    await this.lockWorkspace(workspaceRoot);
+
     const firstInit = await access(workspaceRoot, F_OK)
       .then(() => false)
       .catch(async () => {
@@ -83,12 +89,13 @@ export class ReposService {
   async checkoutCommit(project: Project, commitNumber: string) {
     const git = await this.getGit(project);
     try {
-      await git.checkout([commitNumber]);
+      await git.fetch(DEFAULT_REMOTE_NAME);
     } catch (err) {
       if (err.message.includes("couldn't find remote ref nonexistent")) {
         throw new NotFoundException(err.message);
       }
       throw err;
     }
+    await git.checkout([commitNumber]);
   }
 }