fix(cli): make WSL image paste use PowerShell STA + PNG format

.changeset/wsl-clipboard-image-sta.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix WSL image paste by running the Windows clipboard helper in STA mode and preferring the PNG clipboard format.

apps/kimi-code/src/utils/clipboard/clipboard-image.ts

@@ -309,11 +309,16 @@ function readClipboardImageViaXclip(): ClipboardImage | null {
  * Linux clipboard. PowerShell reaches the Windows clipboard directly;
  * we round-trip via a temp PNG because binary stdout is unreliable
  * across the WSL interop boundary.
+ *
+ * WinForms Clipboard APIs require a single-threaded apartment — without
+ * `-STA`, `GetImage()` silently returns $null under `powershell.exe`
+ * (default MTA), so Ctrl+V appeared to do nothing in WSL (see #2425).
+ * Prefer the PNG clipboard format when present; fall back to GetImage().
  */
-function readClipboardImageViaPowerShell(): ClipboardImage | null {
+function readClipboardImageViaPowerShell(run: RunCommand): ClipboardImage | null {
   const tmpFile = join(tmpdir(), `kimi-wsl-clip-${randomUUID()}.png`);
   try {
-    const winPathResult = runCommand('wslpath', ['-w', tmpFile], {
+    const winPathResult = run('wslpath', ['-w', tmpFile], {
       timeoutMs: DEFAULT_LIST_TIMEOUT_MS,
     });
     if (!winPathResult.ok) return null;
@@ -324,14 +329,33 @@ function readClipboardImageViaPowerShell(): ClipboardImage | null {
       'Add-Type -AssemblyName System.Windows.Forms',
       'Add-Type -AssemblyName System.Drawing',
       '$path = $env:KIMI_WSL_CLIPBOARD_IMAGE_PATH',
-      '$img = [System.Windows.Forms.Clipboard]::GetImage()',
-      "if ($img) { $img.Save($path, [System.Drawing.Imaging.ImageFormat]::Png); Write-Output 'ok' } else { Write-Output 'empty' }",
+      '$ok = $false',
+      '$obj = [System.Windows.Forms.Clipboard]::GetDataObject()',
+      "if ($obj -and $obj.GetDataPresent('PNG')) {",
+      "  $stream = $obj.GetData('PNG')",
+      '  if ($stream -is [System.IO.MemoryStream]) {',
+      "    [System.IO.File]::WriteAllBytes($path, $stream.ToArray()); $ok = $true",
+      '  }',
+      '}',
+      'if (-not $ok) {',
+      '  $img = [System.Windows.Forms.Clipboard]::GetImage()',
+      '  if ($img) {',
+      '    $img.Save($path, [System.Drawing.Imaging.ImageFormat]::Png)',
+      '    $ok = $true',
+      '  }',
+      '}',
+      "if ($ok) { Write-Output 'ok' } else { Write-Output 'empty' }",
     ].join('; ');
 
-    const result = runCommand('powershell.exe', ['-NoProfile', '-Command', psScript], {
-      timeoutMs: DEFAULT_POWERSHELL_TIMEOUT_MS,
-      env: { ...process.env, KIMI_WSL_CLIPBOARD_IMAGE_PATH: winPath },
-    });
+    // `-STA` is required for WinForms clipboard access from powershell.exe.
+    const result = run(
+      'powershell.exe',
+      ['-STA', '-NoProfile', '-NonInteractive', '-Command', psScript],
+      {
+        timeoutMs: DEFAULT_POWERSHELL_TIMEOUT_MS,
+        env: { ...process.env, KIMI_WSL_CLIPBOARD_IMAGE_PATH: winPath },
+      },
+    );
     if (!result.ok) return null;
     if (result.stdout.toString('utf-8').trim() !== 'ok') return null;
 
@@ -424,7 +448,7 @@ export async function readClipboardMedia(options?: {
       image = readClipboardImageViaWlPaste() ?? readClipboardImageViaXclip();
     }
     if (image === null && wsl) {
-      image = readClipboardImageViaPowerShell();
+      image = readClipboardImageViaPowerShell(run);
     }
     if (image === null && !wayland) {
       const nativeFileMedia = await readClipboardFileMediaViaNativeText(clip);

apps/kimi-code/test/utils/clipboard/clipboard-image.test.ts

@@ -135,6 +135,73 @@ describe('readClipboardMedia', () => {
     expect(getImageBinary).not.toHaveBeenCalled();
   });
 
+  it('reads a WSL clipboard image through powershell.exe -STA (WinForms requires STA)', async () => {
+    const imageBytes = png(8, 8);
+    let linuxTmpPath = '';
+    const runCommand = vi.fn((command: string, args: string[], options?: { env?: NodeJS.ProcessEnv }) => {
+      if (command === 'wslpath') {
+        linuxTmpPath = args[1] ?? '';
+        return { ok: true, stdout: Buffer.from('C:\\Users\\test\\AppData\\Local\\Temp\\kimi.png') };
+      }
+      if (command === 'powershell.exe') {
+        expect(args).toContain('-STA');
+        expect(args).toContain('-NoProfile');
+        expect(args).toContain('-NonInteractive');
+        expect(args).toContain('-Command');
+        expect(options?.env?.['KIMI_WSL_CLIPBOARD_IMAGE_PATH']).toBe(
+          'C:\\Users\\test\\AppData\\Local\\Temp\\kimi.png',
+        );
+        // PowerShell writes via the Windows path; under WSL that is the same inode
+        // as the Linux temp file created before wslpath.
+        writeFileSync(linuxTmpPath, imageBytes);
+        return { ok: true, stdout: Buffer.from('ok\n') };
+      }
+      // wl-paste / xclip miss on WSL so the PowerShell fallback runs.
+      return { ok: false, stdout: Buffer.alloc(0) };
+    });
+
+    const media = await readClipboardMedia({
+      platform: 'linux',
+      env: { WSL_DISTRO_NAME: 'Ubuntu' },
+      clipboard: fakeClipboard({}),
+      runCommand,
+    });
+
+    expect(media).toEqual({
+      kind: 'image',
+      bytes: imageBytes,
+      mimeType: 'image/png',
+    });
+    expect(runCommand).toHaveBeenCalledWith(
+      'powershell.exe',
+      expect.arrayContaining(['-STA', '-NoProfile', '-NonInteractive', '-Command']),
+      expect.objectContaining({
+        env: expect.objectContaining({ KIMI_WSL_CLIPBOARD_IMAGE_PATH: expect.any(String) }),
+      }),
+    );
+  });
+
+  it('returns null when the WSL PowerShell clipboard fallback reports empty', async () => {
+    const runCommand = vi.fn((command: string) => {
+      if (command === 'wslpath') {
+        return { ok: true, stdout: Buffer.from('C:\\Temp\\kimi.png') };
+      }
+      if (command === 'powershell.exe') {
+        return { ok: true, stdout: Buffer.from('empty\n') };
+      }
+      return { ok: false, stdout: Buffer.alloc(0) };
+    });
+
+    const media = await readClipboardMedia({
+      platform: 'linux',
+      env: { WSL_DISTRO_NAME: 'Ubuntu' },
+      clipboard: fakeClipboard({}),
+      runCommand,
+    });
+
+    expect(media).toBeNull();
+  });
+
   it('rejects pasted videos larger than 100 MB', async () => {
     const dir = mkdtempSync(join(tmpdir(), 'kimi-code-clip-'));
     try {