fix: stabilize streamed answer completion

2026-07-19 15:26:55 +08:00
parent c22dea9979
commit 695a969c57
4 changed files with 141 additions and 37 deletions
@@ -0,0 +1,54 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import test from "node:test";
+
+import { chatMessageViews } from "../src/lib/chat-message-view.ts";
+
+const pageSource = readFileSync(new URL("../src/app/page.tsx", import.meta.url), "utf8");
+
+const previousMessages = [
+  { role: "user", text: "问题" },
+] as const;
+
+test("keeps the assistant render identity stable when streaming settles", () => {
+  // Given: one assistant answer exists first as a transient stream.
+  const streaming = chatMessageViews(previousMessages, true, "完整答案");
+
+  // When: the same answer becomes part of the persisted transcript.
+  const settled = chatMessageViews([
+    ...previousMessages,
+    { role: "assistant", text: "完整答案" },
+  ], false, "");
+
+  // Then: React receives the same key and can reuse the existing message shell.
+  assert.equal(streaming.at(-1)?.renderKey, settled.at(-1)?.renderKey);
+  assert.equal(streaming.at(-1)?.state, "streaming");
+  assert.equal(settled.at(-1)?.state, "settled");
+});
+
+test("does not duplicate a completed assistant answer while loading state settles", () => {
+  // Given: the final answer has entered the transcript while request cleanup lags.
+  const completedMessages = [
+    ...previousMessages,
+    { role: "assistant", text: "完整答案" },
+  ] as const;
+
+  // When: the render view is derived with the old loading flag still true.
+  const views = chatMessageViews(completedMessages, true, "完整答案");
+
+  // Then: only the persisted answer is rendered.
+  assert.equal(views.length, completedMessages.length);
+  assert.equal(views.at(-1)?.state, "settled");
+});
+
+test("keeps the suggestion row height stable while an answer streams", () => {
+  // Given: a completed answer already supplies follow-up suggestions.
+  const suggestionBlock = pageSource.match(/\{activeSuggestions\.length > 0[\s\S]*?<div className="composer-suggestions"[\s\S]*?<\/div>\n\s*\)\}/);
+
+  // When: the suggestion visibility and button state are inspected.
+  assert.ok(suggestionBlock);
+
+  // Then: loading disables the actions without removing their layout slot.
+  assert.doesNotMatch(suggestionBlock[0].split("<div className=", 1)[0], /!isLoading/);
+  assert.match(suggestionBlock[0], /disabled=\{[^}]*isLoading/);
+});