fix(auto-reply): preserve newlines in stripInlineStatus and extractInlineSimpleCommand

The /\s+/g whitespace normalizer collapsed newlines along with spaces/tabs,
destroying paragraph structure in multi-line messages before they reached
the LLM. Use /[^\S\n]+/g to only collapse horizontal whitespace while
preserving line breaks.

Closes #32216

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/auto-reply/reply/reply-inline.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it } from "vitest";
+import { extractInlineSimpleCommand, stripInlineStatus } from "./reply-inline.js";
+
+describe("stripInlineStatus", () => {
+  it("strips /status directive from message", () => {
+    const result = stripInlineStatus("/status hello world");
+    expect(result.cleaned).toBe("hello world");
+    expect(result.didStrip).toBe(true);
+  });
+
+  it("preserves newlines in multi-line messages", () => {
+    const result = stripInlineStatus("first line\nsecond line\nthird line");
+    expect(result.cleaned).toBe("first line\nsecond line\nthird line");
+    expect(result.didStrip).toBe(false);
+  });
+
+  it("preserves newlines when stripping /status", () => {
+    const result = stripInlineStatus("/status\nfirst paragraph\n\nsecond paragraph");
+    expect(result.cleaned).toBe("first paragraph\n\nsecond paragraph");
+    expect(result.didStrip).toBe(true);
+  });
+
+  it("collapses horizontal whitespace but keeps newlines", () => {
+    const result = stripInlineStatus("hello   world\n  indented  line");
+    expect(result.cleaned).toBe("hello world\n indented line");
+    // didStrip is true because whitespace normalization changed the string
+    expect(result.didStrip).toBe(true);
+  });
+
+  it("returns empty string for whitespace-only input", () => {
+    const result = stripInlineStatus("   ");
+    expect(result.cleaned).toBe("");
+    expect(result.didStrip).toBe(false);
+  });
+});
+
+describe("extractInlineSimpleCommand", () => {
+  it("extracts /help command", () => {
+    const result = extractInlineSimpleCommand("/help some question");
+    expect(result?.command).toBe("/help");
+    expect(result?.cleaned).toBe("some question");
+  });
+
+  it("preserves newlines after extracting command", () => {
+    const result = extractInlineSimpleCommand("/help first line\nsecond line");
+    expect(result?.command).toBe("/help");
+    expect(result?.cleaned).toBe("first line\nsecond line");
+  });
+
+  it("returns null for empty body", () => {
+    expect(extractInlineSimpleCommand("")).toBeNull();
+    expect(extractInlineSimpleCommand(undefined)).toBeNull();
+  });
+});

src/auto-reply/reply/reply-inline.ts

@@ -24,7 +24,10 @@ export function extractInlineSimpleCommand(body?: string): {
   if (!command) {
     return null;
   }
-  const cleaned = body.replace(match[0], " ").replace(/\s+/g, " ").trim();
+  const cleaned = body
+    .replace(match[0], " ")
+    .replace(/[^\S\n]+/g, " ")
+    .trim();
   return { command, cleaned };
 }
 
@@ -36,6 +39,11 @@ export function stripInlineStatus(body: string): {
   if (!trimmed) {
     return { cleaned: "", didStrip: false };
   }
-  const cleaned = trimmed.replace(INLINE_STATUS_RE, " ").replace(/\s+/g, " ").trim();
+  // Use [^\S\n]+ instead of \s+ to only collapse horizontal whitespace,
+  // preserving newlines so multi-line messages keep their paragraph structure.
+  const cleaned = trimmed
+    .replace(INLINE_STATUS_RE, " ")
+    .replace(/[^\S\n]+/g, " ")
+    .trim();
   return { cleaned, didStrip: cleaned !== trimmed };
 }