[BUG] VS Code sidebar fails to restore (claudeVSCodeSidebarSecondary) on Windows \\?\ workspace paths — uncaught realpathSync EISDIR

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

On Windows, the VS Code extension fails to restore the Claude Code sidebar view claudeVSCodeSidebarSecondary when the workspace was opened with a Windows extended-length / verbatim path (\\?\D:\...).

VS Code then stores the folder as:

file://?/d:/Work/MyProject

(workspace.json: "folder": "file://%3F/d%3A/...")

resolveWebviewView does an uncaught fs.realpathSync(workspaceFolder.uri.fsPath). Node's realpathSync on a \\?\D:\... path throws:

EISDIR: illegal operation on a directory, lstat 'D:'

The webview never loads. The same folder opened via File → Open Folder (normal file:///d:/... URI) works.

This is still broken on Claude Code for VS Code 2.1.246. Related #43101 (lstat 'd:' on a D: workspace) was closed by the stale bot without a fix; that report did not identify the \\?\ URI form.

What Should Happen?

The sidebar should load for any valid Windows folder VS Code can open, including:

• \\?\D:\Work\MyProject (verbatim / extended-length)
• drive-letter-only roots (D: / D:\)

realpathSync should strip \\?\ / \\?\UNC\ (and treat D: as D:\) and/or be wrapped in try/catch like the nearby session-groups path already is.

Error Messages/Logs

EISDIR: illegal operation on a directory, lstat 'D:': Error: EISDIR: illegal operation on a directory, lstat 'D:'
    at Object.realpathSync (node:fs:2759:25)
    at Object.<anonymous> (node:electron/js2c/node_init:2:5778)
    at Xo.resolveWebviewView (.../anthropic.claude-code-2.1.246-win32-x64/extension.js:888:10022)

UI: Error restoring view: claudeVSCodeSidebarSecondary (localized: 还原视图时出错: claudeVSCodeSidebarSecondary)

Call site in the shipped extension (minified extension.js around resolveWebviewView):

let X = vscode.workspace.workspaceFolders?.map(G => G.uri.fsPath) || [];
let Y = fs.realpathSync(X[0] || os.homedir()).normalize("NFC");

There is no try/catch. A nearby helper (session groups) already does:

try { Q = fs.realpathSync($).normalize("NFC") } catch {}

Local Node repro (any existing folder on D:):

require('fs').realpathSync('\\\\?\\D:\\Work\\MyProject')
// Error: EISDIR: illegal operation on a directory, lstat 'D:'

require('fs').realpathSync('D:\\Work\\MyProject')
// => D:\Work\MyProject

Steps to Reproduce

1. Windows 11, install Claude Code for VS Code 2.1.246.
2. Open a folder using a verbatim path, e.g. from cmd:

``bat
code --folder-uri "file://?/d:/Work/MyProject"
``

or launch VS Code with code "\\?\D:\Work\MyProject" (this is what some host apps do after Rust canonicalize()).

1. Confirm User/workspaceStorage/<id>/workspace.json contains file://%3F/d%3A/....
2. Open the Claude Code secondary sidebar.
3. The view shows the restore error; renderer.log has the realpathSync / lstat 'D:' stack.

Control: File → Open Folder on the same directory → URI is file:///d%3A/... → sidebar loads.

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

Claude Code Version

2.1.246 (VS Code extension anthropic.claude-code-2.1.246-win32-x64); CLI 2.1.241 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

• VS Code: 1.134.0 (commit 110a328ea54b42367b803ec53ee0bf52ef26b419), Windows x64
• Trigger in this case: another desktop app spawned code.cmd with a path from Rust Path::canonicalize() (adds \\?\ on Windows). Any launcher that does that will hit this.
• Related: #43101 (same lstat 'd:' / claudeVSCodeSidebarSecondary, closed stale / not_planned), #16634, #34678, #72747 (same view id, different path bugs)
• Suggested fix: sanitize \\?\ / \\?\UNC\ and ^[A-Za-z]:$ before realpathSync, and catch EISDIR/ENOENT falling back to path.resolve, matching the existing session-groups try/catch.