feat: 统一路径处理——UNC/软链接分类/html 路由平台守卫（#65 #67 #43 #79 #115）

- fs-tree: requireAbsolute 改用 path.isAbsolute（win32 UNC 放行、C:foo 仍拒）；
  目录列表仅对 symlink 行 stat 一次，暴露 isSymlink/broken，目录软链接可展开
- html-route: UNC 路径经 '//' 标记编码往返；标记仅在 Windows 风格会话启用，
  POSIX '//' 绝对路径不再被误判（平台守卫）
- client: isAbsolutePath/isWindowsStylePath 镜像 + resolveSidebarPath 识别 UNC，
  htmlUrl 以会话 cwd 形态传递平台信号；FsEntry 增加 isSymlink/broken
- explorer: 软链接行链接徽标、悬空链接标红 + tooltip（issue #65）
- 测试: tests/platform.ts 守卫助手；win32 专属用例改为 skipIf 可见跳过，
  补 POSIX 反向分支与 UNC 矩阵；新增 fs-tree-symlink.spec

README.md

@@ -21,7 +21,7 @@
 
 ## ✨ 功能一览
 
-- **🗂️ 文件工作台**：资源管理器（懒加载目录树）+ CodeMirror 编辑器；图片 / Markdown / HTML / PDF / Office 内联预览
+- **🗂️ 文件工作台**：资源管理器（懒加载目录树；软链接按目标类型展示——目录软链接可展开、失效链接标红）+ CodeMirror 编辑器；图片 / Markdown / HTML / PDF / Office 内联预览
 - **🌐 内嵌浏览器**：多开网页 tab，后退 / 前进 / 刷新；内容运行在沙箱 iframe；外链默认按协议分流——HTTP 在侧边栏打开、HTTPS 走系统浏览器（设置页可分别调整）
 - **💻 真实终端**：xterm.js + node-pty 真实 shell，断线重连回放；可选为模型注入 `terminal_*` 工具
 - **🌿 Git 面板**：真 diff + VSCode 式 diff tab、历史、右键暂存 / 提交 / 还原

README_EN.md

@@ -21,7 +21,7 @@
 
 ## ✨ Features
 
-- **🗂️ File Workbench**: file explorer (lazy-loading tree) + CodeMirror editor; inline preview for images / Markdown / HTML / PDF / Office
+- **🗂️ File Workbench**: file explorer (lazy-loading tree; symlinks show their target kind — directory links expand, dangling links flagged) + CodeMirror editor; inline preview for images / Markdown / HTML / PDF / Office
 - **🌐 Embedded Browser**: multiple web tabs with back / forward / refresh; content runs in a sandboxed iframe; external links are routed by protocol by default — HTTP opens in the sidebar, HTTPS goes to the system browser (both adjustable in settings)
 - **💻 Real Terminal**: xterm.js + node-pty real shell, reconnect with transcript replay; optionally injects `terminal_*` tools for the model
 - **🌿 Git Panel**: real diff + VSCode-style diff tabs, history, right-click to stage / commit / revert

docs/external-plugin-guide.md

@@ -480,7 +480,7 @@ const { value } = await res.json()   // 错误时 { ok: false, error: { code, me
 | 方法 | 说明 |
 |---|---|
 | `session.cwd` | 会话权威 cwd（`{ cwd, root, parent }`） |
-| `fs.tree` | 目录列表（`{ path, entries: FsEntry[], truncated }`） |
+| `fs.tree` | 目录列表（`{ path, entries: FsEntry[], truncated }`；FsEntry 含 `isSymlink`/`broken`，目录软链接的 `isDir` 按目标类型） |
 | `fs.read` | 读文件：文本返回 `{ kind: 'text', content, truncated }`；二进制返回 `{ kind: 'binary', size, truncated, head }`（head = base64 前 4KB） |
 | `fs.write` | 原子写文件 |
 | `git.status` / `git.diff` / `git.log` 等 | 全套 Git 只读 + 写操作 |

src/client/ExplorerView.tsx

@@ -14,7 +14,7 @@ import { useCallback, useEffect, useRef, useState, type MouseEvent, type ReactNo
 import clsx from 'clsx'
 import {
   IconCodeOutline16, IconCopyOutline16, IconDownloadOutline16, IconFolderClose16, IconFolderOpen16,
-  IconRefreshOutline16, Menu, writeClipboard,
+  IconLinkOutline16, IconRefreshOutline16, Menu, writeClipboard,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import { api, downloadUrl, type FsEntry } from './api.ts'
 import { relativeTo } from './paths.ts'
@@ -163,6 +163,7 @@ export function ExplorerView(props: {
             >
               {isOpen ? <IconFolderOpen16 size={14} /> : <IconFolderClose16 size={14} />}
               <span className={css.explorerName}>{entry.name}</span>
+              {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
               {rowActions(entry)}
             </div>
             {isOpen && renderLevel(entry.path, depth + 1)}
@@ -174,9 +175,9 @@ export function ExplorerView(props: {
           key={entry.path}
           role="button"
           tabIndex={0}
-          className={clsx(css.explorerRow, entry.hidden && css.explorerHidden)}
+          className={clsx(css.explorerRow, entry.hidden && css.explorerHidden, entry.broken && css.explorerBroken)}
           style={{ paddingLeft: depth * 22 + 6 }}
-          title={entry.path}
+          title={entry.broken ? `${entry.path} — ${t('brokenSymlink')}` : entry.path}
           onClick={() => { onOpenFile(entry.path) }}
           onKeyDown={(event) => {
             if (event.key === 'Enter' || event.key === ' ') {
@@ -188,6 +189,7 @@ export function ExplorerView(props: {
         >
           <IconCodeOutline16 size={14} />
           <span className={css.explorerName}>{entry.name}</span>
+          {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
           {rowActions(entry)}
         </div>
       )

src/client/api.ts

@@ -8,6 +8,7 @@
  */
 import { encodeHtmlUrl } from '../html-route.ts'
 import type { BrowserProbeResult } from './browser.ts'
+import { isWindowsStylePath } from './paths.ts'
 
 /** One wire failure. */
 export class SidebarApiError extends Error {
@@ -25,6 +26,10 @@ export interface FsEntry {
   path: string
   isDir: boolean
   hidden: boolean
+  /** Whether the row is a symlink; `isDir` then describes the link's target. */
+  isSymlink: boolean
+  /** For symlinks: the target is missing or unreadable (stat failed). */
+  broken: boolean
 }
 
 /** Git status entry (host git shape). */
@@ -207,9 +212,13 @@ function fileUrl(scope: SessionScope, path: string, download: boolean): string {
   return `/sidebar/file?${params.toString()}`
 }
 
-/** Absolute URL of the HTML preview route (see html-route.ts): the path is
- *  fully encoded so the previewed page's relative assets resolve back into
- *  the same route with the session scope intact. */
+/**
+ * Absolute URL of the HTML preview route (see html-route.ts): the path is
+ * fully encoded so the previewed page's relative assets resolve back into
+ * the same route with the session scope intact. The session cwd's shape
+ * supplies the platform guard for the UNC marker (the browser OS may differ
+ * from the host OS, so no client-side platform detection is used).
+ */
 export function htmlUrl(scope: SessionScope, path: string): string {
-  return encodeHtmlUrl(scope.sessionId, path)
+  return encodeHtmlUrl(scope.sessionId, path, isWindowsStylePath(scope.cwd ?? ''))
 }

src/client/locales.ts

@@ -17,6 +17,7 @@ export const zh = {
   editor: '编辑器',
   newTab: '新建标签页',
   openExplorer: '资源管理器',
+  brokenSymlink: '失效的软链接',
   openGit: 'Git 面板',
   newTerminal: '新终端',
   terminalLimit: '终端数量已达上限 (3)',
@@ -239,6 +240,7 @@ export const en: Record<keyof typeof zh, string> = {
   editor: 'Editor',
   newTab: 'New tab',
   openExplorer: 'Explorer',
+  brokenSymlink: 'Broken symlink',
   openGit: 'Git panel',
   newTerminal: 'New terminal',
   terminalLimit: 'Terminal limit reached (3)',

src/client/paths.ts

@@ -3,8 +3,38 @@
  * the session cwd (for the @-reference button and "copy relative path").
  * The fs-tree joins with '/' even on Windows, so both separators normalize
  * to '/' before comparison.
+ *
+ * This module is dependency-free (no node:path in the client bundle): the
+ * host is the authority for path semantics, so these mirrors deliberately
+ * accept a SUPERSET of absolute forms — anything a Windows host would emit
+ * (drive letters, UNC) plus POSIX roots. A form the host would reject
+ * (e.g. a backslash UNC path on a POSIX host) passes through here and then
+ * fails loudly in the host's requireAbsolute instead of being silently
+ * joined onto the cwd.
  */
 
+/**
+ * Whether a path looks like it belongs to a Windows-style session: a drive
+ * letter or any backslash (UNC shares, and drive paths in general).
+ * Used as the platform signal for the html route's UNC marker — the client
+ * cannot read process.platform (the browser OS may differ from the host),
+ * but the session cwd shape is authoritative.
+ */
+export function isWindowsStylePath(path: string): boolean {
+  return path.includes('\\') || /^[A-Za-z]:[\\/]/.test(path)
+}
+
+/**
+ * Mirror of the host's absolute-path notion (see fs-tree.requireAbsolute):
+ * POSIX roots, Windows drive letters, and Windows UNC network shares in
+ * both backslash (`\\server\share\...`) and forward-slash
+ * (`//server/share/...`) form. Deliberately a superset — see the module
+ * comment — so a produced UNC path is never joined onto the cwd.
+ */
+export function isAbsolutePath(path: string): boolean {
+  return path.startsWith('/') || /^[A-Za-z]:[\\/]/.test(path) || /^[\\/]{2}[^\\/]/.test(path)
+}
+
 /**
  * The path relative to the session's working directory.
  * @param cwd - the explorer root (absolute).

src/client/produced-files.ts

@@ -6,6 +6,7 @@
  * Kept dependency-free so the takeover logic is unit-testable and the
  * replica is easy to diff against upstream when it drifts.
  */
+import { isAbsolutePath } from './paths.ts'
 
 /** Paths a tool-result view reports as produced, by render intent. */
 export function producedPaths(view: unknown): readonly string[] {
@@ -76,10 +77,13 @@ export function selectProducedFiles(owner: unknown): readonly string[] | null {
   return paths.length === 0 ? null : paths
 }
 
-/** Resolve a (possibly relative) path against the session cwd for the sidebar. */
+/**
+ * Resolve a (possibly relative) path against the session cwd for the sidebar.
+ * Absolute detection mirrors the host (see client/paths.isAbsolutePath):
+ * POSIX roots, drive letters and UNC shares must not be joined onto the cwd.
+ */
 export function resolveSidebarPath(cwd: string | undefined, path: string): string {
-  const absolute = path.startsWith('/') || /^[A-Za-z]:[\\/]/.test(path)
-  if (absolute) return path
+  if (isAbsolutePath(path)) return path
   const base = cwd ?? ''
   if (base === '') return path
   const separator = base.includes('\\') ? '\\' : '/'

src/client/sidebar.module.css

@@ -703,6 +703,18 @@
   opacity: 0.45;
 }
 
+/* The link badge on symlink rows (folder and file rows alike). */
+.explorerSymlink {
+  flex: none;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* A symlink whose target is missing: error ink on the name (the row stays
+   clickable — the editor surfaces the read failure). */
+.explorerBroken .explorerName {
+  color: var(--dsw-alias-state-error-primary);
+}
+
 .explorerName {
   overflow: hidden;
   text-overflow: ellipsis;

src/fs-tree.ts

@@ -2,11 +2,13 @@
  * Single-level directory listing for the sidebar explorer. Streams the level
  * with opendir, sorts directories first then names (case-insensitive), and
  * marks POSIX-hidden entries (dot-prefixed) for dimmed display. Symlinks are
- * reported as files without probing their target — the explorer shows what
- * dirent says, keeping the read cheap for arbitrarily large levels.
+ * stat'ed once to expose their target kind — a symlink to a directory
+ * expands like a directory — and dangling links are flagged broken. The
+ * probe runs only for entries that are actually symlinks, so levels without
+ * links stay as cheap as before.
  */
-import { opendir } from 'node:fs/promises'
-import { basename, dirname, join, resolve } from 'node:path'
+import { opendir, stat } from 'node:fs/promises'
+import { basename, dirname, isAbsolute, join, resolve } from 'node:path'
 import { SidebarError } from './wire.ts'
 
 /** One explorer row. */
@@ -15,6 +17,10 @@ export interface SidebarFsEntry {
   path: string
   isDir: boolean
   hidden: boolean
+  /** Whether the row is a symlink; `isDir` then describes the link's target. */
+  isSymlink: boolean
+  /** For symlinks: the target is missing or unreadable (stat failed). */
+  broken: boolean
 }
 
 /** One listed level. */
@@ -52,12 +58,22 @@ export async function listDirectory(path: string, maxEntries = 1000): Promise<Si
         overflow += 1
         continue
       }
+      // Platform join: on Windows the level path uses '\' — a hardcoded '/'
+      // would leak mixed separators into every row's path.
+      const fullPath = join(path, dirent.name)
+      const isSymlink = dirent.isSymbolicLink()
+      // Probe the link's target once so a symlinked directory renders as an
+      // expandable directory row. stat follows the chain; any failure
+      // (missing target, ELOOP, permission) leaves the row as a broken
+      // file-shaped link the editor will refuse to read. Non-symlink entries
+      // skip the syscall entirely — dirent already classified them.
+      const info = isSymlink ? await stat(fullPath).catch(() => undefined) : undefined
       rows.push({
         name: dirent.name,
-        // Platform join: on Windows the level path uses '\' — a hardcoded '/'
-        // would leak mixed separators into every row's path.
-        path: join(path, dirent.name),
-        isDir: dirent.isDirectory(),
+        path: fullPath,
+        isDir: info !== undefined ? info.isDirectory() : dirent.isDirectory(),
+        isSymlink,
+        broken: isSymlink && info === undefined,
         hidden: dirent.name.startsWith('.'),
       })
     }
@@ -80,9 +96,15 @@ export function parentOf(path: string): string | undefined {
   return parent === path ? undefined : parent
 }
 
-/** Normalize a caller-supplied path to an absolute, resolved path or throw fs-error. */
+/**
+ * Normalize a caller-supplied path to an absolute, resolved path or throw
+ * fs-error. `path.isAbsolute()` is the OS's own notion of absolute: POSIX
+ * roots (`/...`), Windows drive letters (`C:\...`) and — on win32 — UNC
+ * network shares (`\\server\share\...`); drive-relative forms (`C:foo`)
+ * stay rejected.
+ */
 export function requireAbsolute(path: string): string {
-  if (!path.startsWith('/') && !/^[A-Za-z]:[\\/]/.test(path)) {
+  if (!isAbsolute(path)) {
     throw new SidebarError('fs-error', `"${path}" is not an absolute path`, 400)
   }
   return resolve(path)

src/html-route.ts

@@ -13,6 +13,16 @@
  *   /sidebar/html/S/Users/me/proj/index.html
  *     + ./style.css → /sidebar/html/S/Users/me/proj/style.css
  *   Windows: C:\Users\me\a.html → /sidebar/html/S/C%3A/Users/me/a.html
+ *   Windows UNC (windowsPathStyle): \\server\share\proj\a.html
+ *     → /sidebar/html/S//server/share/proj/a.html  ('//' right after the
+ *       sessionId marks the UNC prefix; the WHATWG URL keeps '//' intact so
+ *       relative assets still resolve inside the same route)
+ *
+ * The `windowsPathStyle` flag is the platform guard: a leading `//` is a
+ * legitimate POSIX absolute path, so the UNC marker is only emitted for
+ * sessions whose cwd shape identifies them as Windows (see the client's
+ * isWindowsStylePath) — otherwise a POSIX `//server/share/...` would decode
+ * back to a backslash UNC form the host then rejects.
  *
  * This module is intentionally dependency-free (no node imports, no wire
  * helpers) so the client bundle can import `encodeHtmlUrl` without tripping
@@ -35,25 +45,32 @@ export type HtmlDecodeResult =
 /** The route prefix both encoders/decoders agree on. */
 export const HTML_ROUTE_PREFIX = '/sidebar/html/'
 
-/** Build the route URL for one absolute file path (client + tests). */
-export function encodeHtmlUrl(sessionId: string, path: string): string {
+/**
+ * Build the route URL for one absolute file path (client + tests).
+ * @param windowsPathStyle - whether the path belongs to a Windows-style
+ * session (drive or UNC). Only then is a `\\`/`//`-prefixed UNC path marked
+ * with the '//' marker; POSIX sessions keep `//` as an ordinary absolute
+ * path (see the module comment for the platform guard rationale).
+ */
+export function encodeHtmlUrl(sessionId: string, path: string, windowsPathStyle = false): string {
+  const unc = windowsPathStyle && /^[\\/]{2}[^\\/]/.test(path)
   const segments = path.split(/[\\/]+/).filter(segment => segment !== '')
-  return `${HTML_ROUTE_PREFIX}${encodeURIComponent(sessionId)}/${segments.map(encodeURIComponent).join('/')}`
+  return `${HTML_ROUTE_PREFIX}${encodeURIComponent(sessionId)}/${unc ? '/' : ''}${segments.map(encodeURIComponent).join('/')}`
 }
 
 /**
  * Decode a route pathname into the session + absolute file path. Rejects
- * a wrong prefix (404), an empty or double-slash path, malformed percent
- * encoding, and a missing sessionId or file path (400). The caller still
- * must bound the decoded path with requireAbsolute + isWithin(cwd) — a
- * decoded `..` segment resolves outside the cwd and is refused there.
+ * a wrong prefix (404), an empty path, malformed percent encoding, and a
+ * missing sessionId or file path (400). The caller still must bound the
+ * decoded path with requireAbsolute + isWithin(cwd) — a decoded `..`
+ * segment resolves outside the cwd and is refused there.
  */
 export function decodeHtmlUrl(pathname: string): HtmlDecodeResult {
   if (!pathname.startsWith(HTML_ROUTE_PREFIX)) {
     return { ok: false, status: 404, message: 'not an html route' }
   }
   const rest = pathname.slice(HTML_ROUTE_PREFIX.length)
-  if (rest === '' || rest.includes('//')) {
+  if (rest === '') {
     return { ok: false, status: 400, message: 'invalid html route path' }
   }
   let segments: string[]
@@ -63,17 +80,32 @@ export function decodeHtmlUrl(pathname: string): HtmlDecodeResult {
     return { ok: false, status: 400, message: 'malformed URL encoding' }
   }
   const [sessionId, ...pathSegments] = segments
-  if (sessionId === undefined || sessionId === '' || pathSegments.length === 0 || pathSegments.some(segment => segment === '')) {
+  if (sessionId === undefined || sessionId === '') {
     return { ok: false, status: 400, message: 'sessionId and file path are required' }
   }
-  // A Windows drive segment ('D:') is the FIRST path segment of an encoded
-  // drive path. Rejoining it with a leading slash would yield '/D:/work/...'
-  // which node's path.resolve() mangles into 'D:\D:\work\...' on Windows —
-  // the html route's isWithin(cwd) fence would then reject every drive path.
-  // Keep the drive form slash-free so requireAbsolute() resolves it verbatim.
-  const first = pathSegments[0] ?? ''
-  const path = /^[A-Za-z]:$/.test(first)
-    ? pathSegments.join('/')
-    : `/${pathSegments.join('/')}`
+  // An empty FIRST path segment is the UNC marker (encodeHtmlUrl emits
+  // '<sid>//server/share/...' for Windows UNC paths); the encoder filters
+  // empty segments everywhere else, so an empty segment can only be the
+  // marker or a malformed URL — both handled here.
+  const unc = pathSegments[0] === ''
+  const tail = unc ? pathSegments.slice(1) : pathSegments
+  if (tail.length === 0 || tail.some(segment => segment === '')) {
+    return { ok: false, status: 400, message: 'sessionId and file path are required' }
+  }
+  let path: string
+  if (unc) {
+    // Rebuild the UNC form \\server\share\... so requireAbsolute() +
+    // isWithin(cwd) see the same path the explorer works with.
+    path = `\\\\${tail.join('\\')}`
+  } else if (/^[A-Za-z]:$/.test(tail[0] ?? '')) {
+    // A Windows drive segment ('D:') is the FIRST path segment of an encoded
+    // drive path. Rejoining it with a leading slash would yield '/D:/work/...'
+    // which node's path.resolve() mangles into 'D:\D:\work\...' on Windows —
+    // the html route's isWithin(cwd) fence would then reject every drive path.
+    // Keep the drive form slash-free so requireAbsolute() resolves it verbatim.
+    path = tail.join('/')
+  } else {
+    path = `/${tail.join('/')}`
+  }
   return { ok: true, ref: { sessionId, path } }
 }

tests/fs-tree-symlink.spec.ts

@@ -0,0 +1,89 @@
+/**
+ * fs-tree symlink listing: the explorer must show a symlink as what it
+ * points at (a symlink to a directory expands like a directory) and flag
+ * links whose target is missing. The host listing keeps the probe cheap:
+ * only entries that are actually symlinks are stat'ed.
+ */
+import { describe, expect, it } from 'vitest'
+import { mkdirSync, mkdtempSync, rmSync, symlinkSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { listDirectory } from '../src/fs-tree.ts'
+
+/**
+ * Symlink creation needs extra privileges on Windows; skip the suite there
+ * rather than fail (mirror of the smoke spec's platform-tolerant fixtures).
+ */
+const canSymlink = (() => {
+  const dir = mkdtempSync(join(tmpdir(), 'dsh-sidebar-symlink-probe-'))
+  try {
+    symlinkSync('target', join(dir, 'link'))
+    return true
+  } catch {
+    return false
+  } finally {
+    rmSync(dir, { recursive: true, force: true })
+  }
+})()
+
+/** A scratch level with real entries plus three symlinks (dir/file/dangling). */
+function makeFixture(): string {
+  const dir = mkdtempSync(join(tmpdir(), 'dsh-sidebar-symlink-'))
+  mkdirSync(join(dir, 'real-dir'))
+  writeFileSync(join(dir, 'real-file.txt'), 'content')
+  symlinkSync(join(dir, 'real-dir'), join(dir, 'link-to-dir'))
+  symlinkSync(join(dir, 'real-file.txt'), join(dir, 'link-to-file'))
+  symlinkSync(join(dir, 'missing-target'), join(dir, 'broken-link'))
+  return dir
+}
+
+describe.skipIf(!canSymlink)('fs-tree symlink listing', () => {
+  it('reports a symlink to a directory as an expandable directory', async () => {
+    const dir = makeFixture()
+    try {
+      const listing = await listDirectory(dir)
+      const row = listing.entries.find(entry => entry.name === 'link-to-dir')
+      expect(row).toMatchObject({ isDir: true, isSymlink: true, broken: false })
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
+  it('reports a symlink to a file as a file with a link badge', async () => {
+    const dir = makeFixture()
+    try {
+      const listing = await listDirectory(dir)
+      const row = listing.entries.find(entry => entry.name === 'link-to-file')
+      expect(row).toMatchObject({ isDir: false, isSymlink: true, broken: false })
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
+  it('flags a dangling symlink as broken', async () => {
+    const dir = makeFixture()
+    try {
+      const listing = await listDirectory(dir)
+      const row = listing.entries.find(entry => entry.name === 'broken-link')
+      expect(row).toMatchObject({ isDir: false, isSymlink: true, broken: true })
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
+  it('leaves regular entries unmarked and sorts symlinked dirs with the directories', async () => {
+    const dir = makeFixture()
+    try {
+      const listing = await listDirectory(dir)
+      const realDir = listing.entries.find(entry => entry.name === 'real-dir')
+      const realFile = listing.entries.find(entry => entry.name === 'real-file.txt')
+      expect(realDir).toMatchObject({ isDir: true, isSymlink: false, broken: false })
+      expect(realFile).toMatchObject({ isDir: false, isSymlink: false, broken: false })
+      // Directory-first ordering counts a symlinked directory as a directory.
+      const dirs = listing.entries.filter(entry => entry.isDir).map(entry => entry.name)
+      expect(dirs).toEqual(['link-to-dir', 'real-dir'])
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+})

tests/fs-tree.spec.ts

@@ -1,43 +1,76 @@
 import { describe, expect, it } from 'vitest'
+import { resolve } from 'node:path'
 import { compareEntries, isWithin, parentOf, requireAbsolute, rootLabel } from '../src/fs-tree.ts'
+import { isPosix, isWin32 } from './platform.ts'
 
 describe('fs-tree', () => {
   it('sorts directories first, then names case-insensitively', () => {
     const rows = [
-      { name: 'b.txt', path: '/x/b.txt', isDir: false, hidden: false },
-      { name: 'A', path: '/x/A', isDir: true, hidden: false },
-      { name: 'a.txt', path: '/x/a.txt', isDir: false, hidden: false },
-      { name: '.hidden', path: '/x/.hidden', isDir: false, hidden: true },
+      { name: 'b.txt', path: '/x/b.txt', isDir: false, hidden: false, isSymlink: false, broken: false },
+      { name: 'A', path: '/x/A', isDir: true, hidden: false, isSymlink: false, broken: false },
+      { name: 'a.txt', path: '/x/a.txt', isDir: false, hidden: false, isSymlink: false, broken: false },
+      { name: '.hidden', path: '/x/.hidden', isDir: false, hidden: true, isSymlink: false, broken: false },
     ]
     expect(rows.sort(compareEntries).map(row => row.name)).toEqual(['A', '.hidden', 'a.txt', 'b.txt'])
   })
 
-  it('derives root labels and parents', () => {
+  it('derives root labels and parents (POSIX-style)', () => {
     // POSIX-style inputs behave identically on both platforms (win32 parses '/'
     // as a separator), so these assertions are platform-independent.
     expect(rootLabel('/Users/me/code')).toBe('code')
     expect(rootLabel('/')).toBe('/')
     expect(parentOf('/Users/me/code')).toBe('/Users/me')
     expect(parentOf('/')).toBeUndefined()
-    // Windows-drive roots and segments, asserted only where win32 semantics apply.
-    if (process.platform === 'win32') {
-      expect(rootLabel('C:\\')).toBe('C:\\')
-      expect(parentOf('C:\\')).toBeUndefined()
-      expect(rootLabel('C:\\Users\\me')).toBe('me')
-      expect(parentOf('C:\\Users\\me')).toBe('C:\\Users')
-    }
   })
 
-  it('accepts absolute paths and rejects relative ones', () => {
+  it.skipIf(!isWin32)('derives root labels and parents for Windows drives', () => {
+    expect(rootLabel('C:\\')).toBe('C:\\')
+    expect(parentOf('C:\\')).toBeUndefined()
+    expect(rootLabel('C:\\Users\\me')).toBe('me')
+    expect(parentOf('C:\\Users\\me')).toBe('C:\\Users')
+  })
+
+  it('accepts POSIX absolute paths and rejects relative ones', () => {
     // resolve() is platform-native: '/a/b' roots to the current drive on win32.
-    expect(requireAbsolute('/a/b')).toBe(process.platform === 'win32' ? '\\a\\b' : '/a/b')
-    if (process.platform === 'win32') {
-      expect(requireAbsolute('C:/proj')).toBe('C:\\proj')
-    }
+    expect(requireAbsolute('/a/b')).toBe(resolve('/a/b'))
     expect(() => requireAbsolute('a/b')).toThrow(/not an absolute path/)
     expect(() => requireAbsolute('../a')).toThrow(/not an absolute path/)
   })
 
+  // Windows-only path semantics — skipped (not silently passing) on POSIX:
+  // drive letters and UNC shares are absolute on win32, drive-relative 'C:foo'
+  // is not.
+  describe.skipIf(!isWin32)('win32 path semantics', () => {
+    it('accepts drive letters and normalizes their separators', () => {
+      expect(requireAbsolute('C:/proj')).toBe('C:\\proj')
+      expect(requireAbsolute('C:\\proj')).toBe('C:\\proj')
+      // A drive path resolves against its own drive, never a bare root.
+      expect(resolve('/a/b')).toMatch(/^[A-Za-z]:/)
+    })
+
+    it('accepts UNC network shares in both separator styles', () => {
+      expect(requireAbsolute('\\\\server\\share\\proj')).toBe('\\\\server\\share\\proj')
+      expect(requireAbsolute('//server/share/proj')).toBe('\\\\server\\share\\proj')
+    })
+
+    it('rejects drive-relative paths', () => {
+      expect(() => requireAbsolute('C:proj')).toThrow(/not an absolute path/)
+    })
+  })
+
+  // POSIX-only path semantics — the reverse branch of the win32 suite: forms
+  // the host can never access must be refused loudly instead of mangled.
+  describe.skipIf(isWin32)('POSIX path semantics', () => {
+    it('rejects Windows drive paths', () => {
+      expect(() => requireAbsolute('C:/proj')).toThrow(/not an absolute path/)
+      expect(() => requireAbsolute('C:\\proj')).toThrow(/not an absolute path/)
+    })
+
+    it('rejects backslash UNC paths (not absolute on POSIX)', () => {
+      expect(() => requireAbsolute('\\\\server\\share\\proj')).toThrow(/not an absolute path/)
+    })
+  })
+
   it('isWithin tolerates separators and (on win32) letter case', () => {
     expect(isWithin('/work/proj', '/work/proj/src/a.ts')).toBe(true)
     expect(isWithin('/work/proj', '/work/proj')).toBe(true)
@@ -54,5 +87,12 @@ describe('fs-tree', () => {
     // Windows drive-root containment.
     expect(isWithin('C:\\', 'C:\\Users\\me\\a.png', 'win32')).toBe(true)
     expect(isWithin('c:\\users', 'C:/USERS/me/b.png', 'win32')).toBe(true)
+    // UNC network-share containment: the '//' share prefix must not defeat
+    // the prefix test, and a sibling share must stay outside. The platform
+    // parameter is injected, so these win32-semantics assertions run on
+    // every host without any platform guard.
+    expect(isWithin('\\\\server\\share\\proj', '\\\\server\\share\\proj\\src\\a.ts', 'win32')).toBe(true)
+    expect(isWithin('\\\\server\\share\\proj', '\\\\server\\share\\proj2\\a.ts', 'win32')).toBe(false)
+    expect(isWithin('\\\\server\\share\\proj', '\\\\other\\share\\a.ts', 'win32')).toBe(false)
   })
 })

tests/html-route.spec.ts

@@ -8,6 +8,7 @@
 import { describe, expect, it } from 'vitest'
 import { resolve } from 'node:path'
 import { decodeHtmlUrl, encodeHtmlUrl } from '../src/html-route.ts'
+import { isWin32 } from './platform.ts'
 
 describe('encodeHtmlUrl', () => {
   it('encodes a POSIX absolute path into route segments', () => {
@@ -20,6 +21,24 @@ describe('encodeHtmlUrl', () => {
       .toBe('/sidebar/html/sess-1/C%3A/Users/me/a.html')
   })
 
+  it('encodes a Windows UNC path with the // marker only for Windows-style sessions', () => {
+    // Backslash UNC is unambiguous: the marker is emitted whenever the
+    // caller declares the session Windows-style.
+    expect(encodeHtmlUrl('sess-1', '\\\\server\\share\\proj\\a.html', true))
+      .toBe('/sidebar/html/sess-1//server/share/proj/a.html')
+    // Forward-slash UNC needs the same marker on a Windows-style session.
+    expect(encodeHtmlUrl('sess-1', '//server/share/proj/a.html', true))
+      .toBe('/sidebar/html/sess-1//server/share/proj/a.html')
+  })
+
+  it('keeps a POSIX // path marker-free (the platform guard)', () => {
+    // A leading // is a legitimate POSIX absolute path: without the
+    // Windows-style flag it must NOT be marked as UNC, or the host would
+    // decode it back into a backslash form it then rejects.
+    expect(encodeHtmlUrl('s-1', '//server/share/a.html'))
+      .toBe('/sidebar/html/s-1/server/share/a.html')
+  })
+
   it('percent-encodes special characters in segments', () => {
     expect(encodeHtmlUrl('s-1', '/a b/中文/100%.html'))
       .toBe('/sidebar/html/s-1/a%20b/%E4%B8%AD%E6%96%87/100%25.html')
@@ -45,13 +64,35 @@ describe('decodeHtmlUrl', () => {
       ok: true,
       ref: { sessionId: 'sess-1', path: 'C:/Users/me/a.html' },
     })
+  })
+
+  it.skipIf(!isWin32)('decoded drive paths resolve back verbatim on win32', () => {
     // The host runs requireAbsolute() over the decoded path: with the old
     // '/C:/...' form node's resolve() produced 'C:\C:\Users\...' (drive
     // doubled) on Windows and the isWithin(cwd) fence rejected every drive
     // path. The slash-free form must resolve back to the original path.
-    if (process.platform === 'win32') {
-      expect(resolve('C:/Users/me/a.html')).toBe('C:\\Users\\me\\a.html')
-    }
+    expect(resolve('C:/Users/me/a.html')).toBe('C:\\Users\\me\\a.html')
+  })
+
+  it('decodes a UNC round-trip back to the network path', () => {
+    const url = encodeHtmlUrl('sess-1', '\\\\server\\share\\proj\\a.html', true)
+    expect(decodeHtmlUrl(url)).toEqual({
+      ok: true,
+      ref: { sessionId: 'sess-1', path: '\\\\server\\share\\proj\\a.html' },
+    })
+  })
+
+  it('decodes a marker-free POSIX // path as a plain absolute path', () => {
+    const url = encodeHtmlUrl('s-1', '//server/share/a.html')
+    expect(decodeHtmlUrl(url)).toEqual({
+      ok: true,
+      ref: { sessionId: 's-1', path: '/server/share/a.html' },
+    })
+  })
+
+  it('refuses a marker-only UNC URL and stray double slashes (400)', () => {
+    expect(decodeHtmlUrl('/sidebar/html/s//').ok).toBe(false)
+    expect(decodeHtmlUrl('/sidebar/html/s//server//x.html').ok).toBe(false)
   })
 
   it('decodes a lowercase-drive Windows path without a leading slash', () => {
@@ -122,4 +163,16 @@ describe('relative asset resolution stays in-route', () => {
     expect(new URL('img/x.png', doc).pathname).toBe('/sidebar/html/s/a/b/img/x.png')
     expect(new URL('../c.css', doc).pathname).toBe('/sidebar/html/s/a/c.css')
   })
+
+  it('relative assets of a UNC document stay inside the same route', () => {
+    // The WHATWG URL preserves the '//' marker during relative resolution,
+    // so ./style.css lands back on the route with the UNC prefix intact.
+    const doc = `http://h${encodeHtmlUrl('s', '\\\\server\\share\\proj\\index.html', true)}`
+    expect(new URL('./style.css', doc).pathname)
+      .toBe('/sidebar/html/s//server/share/proj/style.css')
+    expect(decodeHtmlUrl(new URL('./style.css', doc).pathname)).toEqual({
+      ok: true,
+      ref: { sessionId: 's', path: '\\\\server\\share\\proj\\style.css' },
+    })
+  })
 })

tests/paths.spec.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest'
-import { relativeTo } from '../src/client/paths.ts'
+import { isAbsolutePath, isWindowsStylePath, relativeTo } from '../src/client/paths.ts'
 import { resolveSidebarPath } from '../src/client/produced-files.ts'
+import { htmlUrl } from '../src/client/api.ts'
 
 describe('path helpers', () => {
   it('derives relative paths under the cwd (and "." for the cwd itself)', () => {
@@ -32,4 +33,57 @@ describe('path helpers', () => {
     expect(resolveSidebarPath('C:\\work\\proj', 'C:\\abs\\x.ts')).toBe('C:\\abs\\x.ts')
     expect(resolveSidebarPath('C:\\work\\proj\\', 'C:\\abs\\x.ts')).toBe('C:\\abs\\x.ts')
   })
+
+  it('keeps UNC produced paths absolute instead of joining them onto the cwd', () => {
+    // Pure client function: UNC detection is platform-independent, so these
+    // assertions run on every host without a platform guard.
+    expect(resolveSidebarPath('C:\\work\\proj', '\\\\server\\share\\abs\\x.ts'))
+      .toBe('\\\\server\\share\\abs\\x.ts')
+    expect(resolveSidebarPath('C:\\work\\proj', '//server/share/abs/x.ts'))
+      .toBe('//server/share/abs/x.ts')
+    // A relative path under a UNC cwd joins with backslashes.
+    expect(resolveSidebarPath('\\\\server\\share\\proj', 'src/a.ts'))
+      .toBe('\\\\server\\share\\proj\\src/a.ts')
+  })
+
+  it('mirrors the host absolute-path notion without node:path', () => {
+    expect(isAbsolutePath('/abs/x.ts')).toBe(true)
+    expect(isAbsolutePath('C:\\abs\\x.ts')).toBe(true)
+    expect(isAbsolutePath('C:/abs/x.ts')).toBe(true)
+    expect(isAbsolutePath('\\\\server\\share\\x.ts')).toBe(true)
+    expect(isAbsolutePath('//server/share/x.ts')).toBe(true)
+    expect(isAbsolutePath('C:relative.ts')).toBe(false)
+    expect(isAbsolutePath('rel/x.ts')).toBe(false)
+  })
+
+  it('detects windows-style session paths (platform signal for the html route)', () => {
+    expect(isWindowsStylePath('C:\\work\\proj')).toBe(true)
+    expect(isWindowsStylePath('C:/work/proj')).toBe(true)
+    expect(isWindowsStylePath('\\\\server\\share\\proj')).toBe(true)
+    expect(isWindowsStylePath('//server/share/proj')).toBe(false) // ambiguous form needs the drive/backslash signal
+    expect(isWindowsStylePath('/Users/me/code')).toBe(false)
+  })
+
+  it('htmlUrl marks UNC paths from the file path itself (cwd-independent signal)', () => {
+    // cwd not hydrated yet: the unambiguous backslash UNC path must still
+    // keep its '//' marker, or win32 would decode /server/... against the
+    // current drive and the isWithin fence would reject the preview (403).
+    expect(htmlUrl({ sessionId: 's' }, '\\\\server\\share\\proj\\a.html'))
+      .toBe('/sidebar/html/s//server/share/proj/a.html')
+    // A forward-slash-form cwd (still Windows) does not mask the backslash path.
+    expect(htmlUrl({ sessionId: 's', cwd: '//server/share/proj' }, '\\\\server\\share\\proj\\a.html'))
+      .toBe('/sidebar/html/s//server/share/proj/a.html')
+    // Both cwd and path in the forward-slash UNC form: the '//' path matches
+    // the '//' cwd, so it is UNC and keeps the marker (win32 round-trips).
+    expect(htmlUrl({ sessionId: 's', cwd: '//server/share/proj' }, '//server/share/proj/a.html'))
+      .toBe('/sidebar/html/s//server/share/proj/a.html')
+    // A Windows drive cwd marks forward-slash UNC paths.
+    expect(htmlUrl({ sessionId: 's', cwd: 'C:\\work' }, '//server/share/proj/a.html'))
+      .toBe('/sidebar/html/s//server/share/proj/a.html')
+    // A POSIX session keeps forward-slash paths marker-free.
+    expect(htmlUrl({ sessionId: 's', cwd: '/home/me' }, '//server/share/a.html'))
+      .toBe('/sidebar/html/s/server/share/a.html')
+    expect(htmlUrl({ sessionId: 's', cwd: '/home/me' }, '/home/me/index.html'))
+      .toBe('/sidebar/html/s/home/me/index.html')
+  })
 })

tests/platform.ts

@@ -0,0 +1,13 @@
+/**
+ * Shared platform guards for tests. Use vitest's `describe.skipIf` /
+ * `it.skipIf` with these so platform-specific cases are REPORTED as skipped
+ * on other hosts instead of silently passing through an inline `if` — and
+ * so the opposite branch (e.g. POSIX rejecting drive paths) is always
+ * asserted on the matching host.
+ */
+
+/** True when running on Windows (drive letters / UNC path semantics apply). */
+export const isWin32 = process.platform === 'win32'
+
+/** True on every non-Windows host (POSIX path semantics). */
+export const isPosix = !isWin32