linshenkx/prompt-optimizer · error · TestError

At least one message is required

Error message

At least one message is required

What it means

testCustomConversationStream requires at least one entry in request.messages; an empty or missing array throws TestError 'At least one message is required'. The custom conversation test replays a message list, so an empty list has nothing to send.

Source

Thrown at packages/core/src/services/prompt/service.ts:1113

  // 3. 版本管理逻辑在UI层更容易处理
  //
  // 相比之下，优化操作会创建新的链，所以可以在核心层处理
  // 这种混合架构是经过权衡的设计决策

  /**
   * 自定义会话测试（流式）- 高级模式功能
   */
  async testCustomConversationStream(
    request: CustomConversationRequest,
    callbacks: StreamHandlers,
  ): Promise<void> {
    try {
      // 验证请求
      if (!request.modelKey?.trim()) {
        throw new TestError("", "", "Model key is required");
      }
      if (!request.messages || request.messages.length === 0) {
        throw new TestError("", "", "At least one message is required");
      }

      // 验证模型存在
      const modelConfig = await this.modelManager.getModel(request.modelKey);
      if (!modelConfig) {
        throw new TestError("", "", "Model not found");
      }

      // 处理会话消息：替换变量
      const processedMessages = TemplateProcessor.processConversationMessages(
        request.messages,
        request.variables,
      );

      if (processedMessages.length === 0) {
        throw new TestError("", "", "No valid messages after processing");
      }

View on GitHub (pinned to 3e677b1d9f)

Solutions

1. Ensure at least one message (typically the user's draft) is appended before invoking the test
2. Guard in the UI: disable Test when the conversation list is empty
3. Construct the request only after pushing the current draft message

Example fix

// before
await service.testCustomConversationStream({ modelKey, messages: [] }, handlers);

// after
const messages = [...conversation, { role: 'user', content: draft }];
if (messages.length === 0) return;
await service.testCustomConversationStream({ modelKey, messages }, handlers);

const messages = [...conversation];
if (messages.length === 0) throw new Error('Add at least one message before testing');

const hasMessages = (
  r: { messages?: unknown[] }
): r is { messages: unknown[] } =>
  Array.isArray(r.messages) && r.messages.length > 0;

try {
  await svc.testCustomConversationStream(req, handlers);
} catch (e) {
  if (e instanceof TestError && e.message === 'At least one message is required') {
    // notify user to write a message first
  } else throw e;
}

When it happens

Trigger: Calling testCustomConversationStream with messages: [], messages: undefined, or a messages array that was filtered down to zero entries.

Common situations: Chat editor state cleared before Test clicked; message draft not yet appended to the conversation array; serialization dropping empty-ish message collections.

Understand the failure class

Background: Missing required parameter errors: what 'X is required' and 'the required X param is missing' mean, and how to fix them — this error's family across 27 libraries.

Related errors

• ${label} testCaseId must not be empty.
• Function mode (functionMode) cannot be empty
• CONFIG_INVALID
• Model config cannot be empty
• Messages array cannot be empty

AI-assisted analysis of linshenkx/prompt-optimizer@3e677b1d9f (2026-08-27). Data as JSON: /api/errors/4e14601dfca90868. Report an issue: GitHub.