fix(clipboard): write CRLF line endings on Windows copies

apps/desktop/src/lib/common/__tests__/clipboard.spec.ts

@@ -1,6 +1,10 @@
-import { describe, expect, it, vi } from "vitest";
+import { afterEach, describe, expect, it, vi } from "vitest";
 
-import { copyToClipboard, type ClipboardEnvironment } from "@/lib/common/clipboard";
+import { clipboardLineEndings, copyToClipboard, type ClipboardEnvironment } from "@/lib/common/clipboard";
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
 
 function legacyClipboardEnvironment(activeDialog?: { appendChild: ReturnType<typeof vi.fn>; removeChild: ReturnType<typeof vi.fn> }) {
   const textarea = {
@@ -45,4 +49,41 @@ describe("copyToClipboard", () => {
     expect(body.appendChild).toHaveBeenCalledWith(textarea);
     expect(body.removeChild).toHaveBeenCalledWith(textarea);
   });
+
+  it("writes CRLF line endings on Windows", async () => {
+    vi.spyOn(navigator, "userAgent", "get").mockReturnValue("Mozilla/5.0 (Windows NT 10.0; Win64; x64)");
+    const writeText = vi.fn();
+
+    await copyToClipboard("SELECT 1\nFROM t\nWHERE x = 1", { navigator: { clipboard: { writeText } } });
+
+    expect(writeText).toHaveBeenCalledWith("SELECT 1\r\nFROM t\r\nWHERE x = 1");
+  });
+
+  it("keeps LF line endings off Windows", async () => {
+    vi.spyOn(navigator, "userAgent", "get").mockReturnValue("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)");
+    const writeText = vi.fn();
+
+    await copyToClipboard("SELECT 1\nFROM t", { navigator: { clipboard: { writeText } } });
+
+    expect(writeText).toHaveBeenCalledWith("SELECT 1\nFROM t");
+  });
+});
+
+describe("clipboardLineEndings", () => {
+  it("converts bare LF and CR to CRLF on Windows", () => {
+    expect(clipboardLineEndings("a\nb\rc", "windows")).toBe("a\r\nb\r\nc");
+  });
+
+  it("leaves text that already uses CRLF untouched", () => {
+    expect(clipboardLineEndings("a\r\nb\r\n", "windows")).toBe("a\r\nb\r\n");
+  });
+
+  it("leaves single-line text untouched on Windows", () => {
+    expect(clipboardLineEndings("SELECT 1", "windows")).toBe("SELECT 1");
+  });
+
+  it("returns the text unchanged on other platforms", () => {
+    expect(clipboardLineEndings("a\nb", "macos")).toBe("a\nb");
+    expect(clipboardLineEndings("a\nb", "linux")).toBe("a\nb");
+  });
 });

apps/desktop/src/lib/common/clipboard.ts

@@ -1,4 +1,5 @@
 import { isTauriRuntime } from "@/lib/backend/tauriRuntime";
+import { getPlatform, type Platform } from "@/lib/backend/platform";
 
 interface ClipboardApi {
   readText?: () => Promise<string> | string;
@@ -42,6 +43,21 @@ export interface ClipboardEnvironment {
   document?: ClipboardDocument;
 }
 
+/**
+ * Rewrites the line endings of text destined for the system clipboard.
+ *
+ * Windows native edit controls (the Win32 EDIT control, and applications built
+ * on it such as PowerBuilder) only treat CRLF as a line break, so text copied
+ * with bare LF arrives as a single line. Other platforms keep LF.
+ *
+ * Existing CRLF pairs are matched before bare CR and LF so that already
+ * normalized text is left byte-identical.
+ */
+export function clipboardLineEndings(text: string, platform: Platform = getPlatform()): string {
+  if (platform !== "windows") return text;
+  return text.replace(/\r\n|\r|\n/g, "\r\n");
+}
+
 export interface ClipboardShortcutEvent {
   key: string;
   metaKey?: boolean;
@@ -136,6 +152,8 @@ export async function readTextFromClipboard(env: ClipboardEnvironment = globalTh
 }
 
 export async function copyToClipboard(text: string, env: ClipboardEnvironment = globalThis as unknown as ClipboardEnvironment): Promise<void> {
+  text = clipboardLineEndings(text);
+
   if (isTauriRuntime(env as unknown as Record<string, unknown>)) {
     try {
       const { writeText } = await import("@tauri-apps/plugin-clipboard-manager");