fix(chat): preserve pasted user message newlines

crates/agent-gateway/test/webui/paste-newline-pipeline.test.mjs

@@ -0,0 +1,148 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { createWebModuleLoader } from "../helpers/load-web-module.mjs";
+
+const loader = createWebModuleLoader();
+const composer = loader.loadModule("src/components/chat/MentionComposer.tsx");
+const composerText = loader.loadModule("src/lib/chat/composerText.ts");
+const draftText = loader.loadModule("src/app/chatDraft.ts");
+const uploadedFiles = loader.loadModule("src/lib/chat/uploadedFiles.ts");
+
+const originalNode = globalThis.Node;
+globalThis.Node = { TEXT_NODE: 3, ELEMENT_NODE: 1 };
+
+test.after(() => {
+  if (originalNode === undefined) delete globalThis.Node;
+  else globalThis.Node = originalNode;
+});
+
+function textNode(text) {
+  return { nodeType: Node.TEXT_NODE, textContent: text };
+}
+
+function elementNode(tagName, childNodes = [], attributes = {}) {
+  return {
+    nodeType: Node.ELEMENT_NODE,
+    tagName,
+    childNodes,
+    getAttribute(name) {
+      return attributes[name] ?? null;
+    },
+    hasAttribute(name) {
+      return Object.hasOwn(attributes, name);
+    },
+  };
+}
+
+function chromiumPasteDom(clipboardText) {
+  const normalized = clipboardText.replace(/\r\n?/g, "\n");
+  const lines = normalized.split("\n");
+  const children = [];
+  if (lines[0]) children.push(textNode(lines[0]));
+  else if (lines.length > 1) children.push(elementNode("DIV", [elementNode("BR")]));
+  for (const line of lines.slice(1)) {
+    children.push(elementNode("DIV", line ? [textNode(line)] : [elementNode("BR")]));
+  }
+  return elementNode("DIV", children);
+}
+
+function draftFromSegments(segments) {
+  const text = segments.map((segment) => segment.text ?? "").join("");
+  return {
+    segments,
+    text,
+    textWithoutLargePastes: text,
+    largePastes: [],
+    skillMentions: [],
+    commitMentions: [],
+    gitFileMentions: [],
+    codeMentions: [],
+    isEmpty: text.trim().length === 0,
+  };
+}
+
+const cases = [
+  ["LF no blank line", "alpha\nbeta"],
+  ["LF one blank line", "alpha\n\nbeta"],
+  ["CRLF one blank line", "alpha\r\n\r\nbeta"],
+  ["CR one blank line", "alpha\r\rbeta"],
+  ["multiple blank lines", "alpha\n\n\nbeta"],
+  ["leading newline", "\nalpha"],
+  ["trailing newline", "alpha\n"],
+  ["Markdown paragraphs", "first paragraph\n\nsecond paragraph"],
+  ["Markdown list", "- one\n- two"],
+  ["Markdown quote", "> quote\n> continued"],
+  ["Markdown code block", "```ts\nconst value = 1;\n```"],
+  ["Markdown table", "| a | b |\n| - | - |\n| 1 | 2 |"],
+  ["Unicode and emoji", "你好🙂\n\nκαλημέρα"],
+  ["long text", `${"x".repeat(20_000)}\n\n${"y".repeat(20_000)}`],
+];
+
+test("clipboard DOM -> composer draft -> outbound -> history preserves logical newlines", () => {
+  for (const [name, clipboardText] of cases) {
+    const expected = clipboardText.replace(/\r\n?/g, "\n");
+    const segments = composer.serializeChildrenToSegments(chromiumPasteDom(clipboardText), new Map());
+    const draft = draftFromSegments(segments);
+    const outbound = draftText.buildTextFromComposerDraft(draft);
+    const message = uploadedFiles.createUserMessageWithUploads(outbound, [], 1);
+    const history = JSON.parse(JSON.stringify(message));
+
+    assert.equal(draft.text, expected, `${name}: composer draft`);
+    assert.equal(outbound, expected, `${name}: outbound payload`);
+    assert.equal(history.content, expected, `${name}: history/replay`);
+    assert.equal(
+      uploadedFiles.getUserMessageDisplayText(history),
+      expected,
+      `${name}: transcript user bubble text`,
+    );
+  }
+});
+
+test("pure whitespace remains structurally intact in the draft but is not sendable", () => {
+  const clipboardText = " \r\n\r\n ";
+  const expected = " \n\n ";
+  const segments = composer.serializeChildrenToSegments(chromiumPasteDom(clipboardText), new Map());
+  const draft = draftFromSegments(segments);
+  assert.equal(draft.text, expected);
+  assert.equal(draftText.buildTextFromComposerDraft(draft), expected);
+  assert.equal(uploadedFiles.createUserMessageWithUploads(expected, [], 1), null);
+});
+
+test("message creation normalizes line endings without trimming logical edge newlines", () => {
+  const input = "\r\nalpha\r\nbeta\r";
+  const expected = "\nalpha\nbeta\n";
+  const message = uploadedFiles.createUserMessageWithUploads(input, [], 1);
+  assert.equal(message.content, expected);
+  assert.equal(uploadedFiles.getUserMessageDisplayText(message), expected);
+});
+
+test("plaintext HTML escaping preserves literal content and logical newlines", () => {
+  assert.equal(
+    composerText.plainTextToContentEditableHtml("<tag>& value\r\nnext"),
+    "&lt;tag&gt;&amp; value\nnext",
+  );
+});
+
+test("composer serialization preserves newlines around mention chips", () => {
+  const root = elementNode("DIV", [
+    textNode("first\n"),
+    elementNode("SPAN", [], {
+      "data-mention-path": "src/App.tsx",
+      "data-mention-kind": "file",
+    }),
+    textNode("\nsecond"),
+  ]);
+  const segments = composer.serializeChildrenToSegments(root, new Map());
+  assert.deepEqual(
+    segments.map((segment) =>
+      segment.type === "text"
+        ? { type: "text", text: segment.text }
+        : { type: segment.type, path: segment.reference?.path },
+    ),
+    [
+      { type: "text", text: "first\n" },
+      { type: "fileMention", path: "src/App.tsx" },
+      { type: "text", text: "\nsecond" },
+    ],
+  );
+});

crates/agent-gateway/web/src/app/GatewayApp.tsx

@@ -31,6 +31,7 @@ import { registerAskUserQuestionAnswerHandler } from "@/lib/chat/askUserQuestion
 import type { ChatFileLink } from "@/lib/chat/chatFileLinks";
 import type { ChatHistorySummary } from "@/lib/chat/chatHistory";
 import { buildModelOptions } from "@/lib/chat/chatPageHelpers";
+import { normalizeLogicalLineEndings } from "@/lib/chat/composerText";
 import type { HistoryMessageRef } from "@/lib/chat/conversationState";
 import {
   adoptHistoryWindowState,
@@ -2392,11 +2393,11 @@ export default function GatewayApp() {
     files: PendingUploadedFile[],
     workdir: string,
   ) {
-    let text = (
+    let text = normalizeLogicalLineEndings(
       isAgentMode && draft.largePastes.length > 0
         ? draft.textWithoutLargePastes
-        : buildTextFromComposerDraft(draft)
-    ).trim();
+        : buildTextFromComposerDraft(draft),
+    );
     let uploadedFiles = files;
 
     if (isAgentMode && draft.largePastes.length > 0) {
@@ -2414,7 +2415,7 @@ export default function GatewayApp() {
         if (apiRef.current?.getActiveAgent().trim() !== agentID) {
           throw new Error("Agent 已切换，已取消发送本次大段粘贴内容。");
         }
-        text = buildTextFromComposerDraft(draft, imported.fileByPasteId).trim();
+        text = buildTextFromComposerDraft(draft, imported.fileByPasteId);
         uploadedFiles = mergePendingUploadedFiles(files, imported.files);
       } finally {
         isImportingPastedTextRef.current = false;

crates/agent-gateway/web/src/app/chatDraft.ts

@@ -4,6 +4,7 @@ import type {
   MentionComposerGitFileMention,
   MentionComposerLargePaste,
 } from "@/components/chat/MentionComposer";
+import { normalizeLogicalLineEndings } from "@/lib/chat/composerText";
 import { formatCodeMentionToken, formatFileMentionToken } from "@/lib/chat/mentionReferences";
 import type { PendingUploadedFile } from "@/lib/chat/uploadedFiles";
 import { withPastedTextDisplayMetadata } from "@/lib/chat/uploadedFiles";
@@ -53,31 +54,33 @@ export function buildTextFromComposerDraft(
   draft: MentionComposerDraft,
   pastedFileById?: Map<string, PendingUploadedFile>,
 ) {
-  return draft.segments
-    .map((segment) => {
-      if (segment.type === "text") {
-        return segment.text;
-      }
-      if (segment.type === "fileMention") {
-        return formatFileMentionToken(segment.reference);
-      }
-      if (segment.type === "skillMention") {
-        return `$${segment.skill.name}`;
-      }
-      if (segment.type === "commitMention") {
-        return formatComposerCommitMention(segment.commit);
-      }
-      if (segment.type === "gitFileMention") {
-        return formatComposerGitFileMention(segment.file);
-      }
-      if (segment.type === "codeMention") {
-        return formatCodeMentionToken(segment.reference);
-      }
-      const file = pastedFileById?.get(segment.paste.id);
-      return file ? `[${segment.paste.label}: ${file.relativePath}]` : segment.paste.text;
-    })
-    .join("")
-    .replace(/\u00A0/g, " ");
+  return normalizeLogicalLineEndings(
+    draft.segments
+      .map((segment) => {
+        if (segment.type === "text") {
+          return segment.text;
+        }
+        if (segment.type === "fileMention") {
+          return formatFileMentionToken(segment.reference);
+        }
+        if (segment.type === "skillMention") {
+          return `$${segment.skill.name}`;
+        }
+        if (segment.type === "commitMention") {
+          return formatComposerCommitMention(segment.commit);
+        }
+        if (segment.type === "gitFileMention") {
+          return formatComposerGitFileMention(segment.file);
+        }
+        if (segment.type === "codeMention") {
+          return formatCodeMentionToken(segment.reference);
+        }
+        const file = pastedFileById?.get(segment.paste.id);
+        return file ? `[${segment.paste.label}: ${file.relativePath}]` : segment.paste.text;
+      })
+      .join("")
+      .replace(/\u00A0/g, " "),
+  );
 }
 
 export async function importPastedTextsAsFiles(params: {