fix(host,client): abort superseded listings on the wire; keep the native swap resolvable

Supersession (newer navigation, path editing, closing, unmount) now
aborts the in-flight listing's request instead of only discarding its
result: the browser mints an AbortController per listing, the signal
rides the workspace face (IWorkspaces.listDirectory gains an optional
signal) onto the fetch carrier, and the Host scan stops with it (817's
cancellation chain). apps/cli keeps both picker packages as dependencies
so the documented one-row cordis.yml swap to the native backend resolves
at boot.

apps/cli/package.json

@@ -49,6 +49,7 @@
     "@deepseek-ai/dsh-fs-policy": "workspace:^",
     "@deepseek-ai/dsh-host-apiproxy": "workspace:^",
     "@deepseek-ai/dsh-host-directory-picker-browse": "workspace:^",
+    "@deepseek-ai/dsh-host-directory-picker-native": "workspace:^",
     "@deepseek-ai/dsh-host-webserver": "workspace:^",
     "@deepseek-ai/dsh-llm": "workspace:^",
     "@deepseek-ai/dsh-llm-deepseek": "workspace:^",

packages/client/runtime/src/client/contract/workspaces.ts

@@ -40,9 +40,10 @@ export interface IWorkspaces {
   /**
    * List one directory level through the Host's `browse` capability.
    * @param path - absolute directory to list; absent lists the Host home directory.
+   * @param signal - aborts the wire request (and the Host's scan) when the caller supersedes it.
    * @returns the level's listing with breadcrumb ancestry.
    */
-  listDirectory(path?: string): Promise<DirectoryListing>
+  listDirectory(path?: string, signal?: AbortSignal): Promise<DirectoryListing>
   /**
    * Create one child directory through the Host's `browse` capability.
    * @param path - absolute existing parent directory.

packages/client/runtime/src/client/workspaces/service.ts

@@ -195,10 +195,11 @@ export class WorkspacesService implements IWorkspaces {
   /**
    * List one directory level through the Host's `browse` capability.
    * @param path - absolute directory to list; absent lists the Host home directory.
+   * @param signal - aborts the wire request (and the Host's scan) when the caller supersedes it.
    * @returns the level's listing with breadcrumb ancestry.
    */
-  async listDirectory(path?: string): Promise<DirectoryListing> {
-    const response = await this.api.host.listDirectory(path === undefined ? {} : { path })
+  async listDirectory(path?: string, signal?: AbortSignal): Promise<DirectoryListing> {
+    const response = await this.api.host.listDirectory(path === undefined ? {} : { path }, signal)
     if (!response.result.ok) throw new DirectoryBrowseError(response.result.error)
     return response.result.value
   }

packages/client/test-runtime/src/workspaces.ts

@@ -115,7 +115,7 @@ export class TestWorkspaces implements IWorkspaces {
    * @param path - absolute directory to list; absent lists the home level.
    * @returns the level's listing.
    */
-  async listDirectory(path?: string): Promise<DirectoryListing> {
+  async listDirectory(path?: string, _signal?: AbortSignal): Promise<DirectoryListing> {
     this.calls.push({ method: 'listDirectory', args: [path] })
     const stub = this.stubs.get('listDirectory')
     if (stub !== undefined) return await (stub(path) as Promise<DirectoryListing>)

packages/host/directory-picker-browse/src/client/DirectoryBrowser.tsx

@@ -27,8 +27,8 @@ import css from './DirectoryBrowser.module.css'
 export interface DirectoryBrowserProps {
   /** Dialog visibility (owner-local; closed unmounts nothing but resets on reopen). */
   open: boolean
-  /** List one directory level (absent path = the Host home directory). */
-  listDirectory: (path?: string) => Promise<DirectoryListing>
+  /** List one directory level (absent path = the Host home directory); the signal aborts a superseded scan on the wire. */
+  listDirectory: (path?: string, signal?: AbortSignal) => Promise<DirectoryListing>
   /** Create one child directory under an existing parent. */
   createDirectory: (path: string, name: string) => Promise<string>
   /** The operator confirmed a directory (the selection, else the listed level). */
@@ -115,6 +115,10 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
   const [creatingFolder, setCreatingFolder] = useState(false)
   const [createError, setCreateError] = useState<string | null>(null)
   const requestSeq = useRef(0)
+  // The in-flight listing's controller: superseding intent aborts the wire
+  // request too — the Host stops scanning — instead of only discarding the
+  // eventual result while the scan keeps consuming host resources.
+  const scanController = useRef<AbortController | null>(null)
   // Bumped on every open/close edge: settlements from a previous open (a
   // pending creation included) must never mutate a reopened dialog.
   const openGeneration = useRef(0)
@@ -130,18 +134,34 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
   useEffect(() => () => {
     requestSeq.current += 1
     openGeneration.current += 1
+    scanController.current?.abort()
   }, [])
   const compositionGuard = {
     onCompositionStart: () => { composingRef.current = true },
     onCompositionEnd: () => { composingRef.current = false },
   }
 
+  /** Newer intent wins: invalidate the pending listing's settlement AND abort its wire request. */
+  const supersede = useCallback((): number => {
+    scanController.current?.abort()
+    scanController.current = null
+    return ++requestSeq.current
+  }, [])
+
+  /** Launch one listing under a fresh controller so a later supersession can abort it. */
+  const launchListing = useCallback((path: string | undefined): { seq: number; scan: Promise<DirectoryListing> } => {
+    const seq = supersede()
+    const controller = new AbortController()
+    scanController.current = controller
+    return { seq, scan: listDirectory(path, controller.signal) }
+  }, [supersede, listDirectory])
+
   /** Replace the whole view with one freshly listed level (no selection). */
   const navigate = useCallback((path?: string) => {
-    const seq = ++requestSeq.current
+    const { seq, scan } = launchListing(path)
     setLoading(true)
     setError(null)
-    listDirectory(path).then((next) => {
+    scan.then((next) => {
       if (seq !== requestSeq.current) return
       setParent(next)
       setSelected(null)
@@ -153,16 +173,16 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       setLoading(false)
       setError(failureText(reason))
     })
-  }, [listDirectory])
+  }, [launchListing])
 
   /** Select a row of the listed level and preview its children on the right. */
   const select = useCallback((entry: DirectoryEntry) => {
-    const seq = ++requestSeq.current
+    const { seq, scan } = launchListing(entry.path)
     setSelected(entry)
     setChild(null)
     setLoading(true)
     setError(null)
-    listDirectory(entry.path).then((next) => {
+    scan.then((next) => {
       if (seq !== requestSeq.current) return
       setChild(next)
       setLoading(false)
@@ -174,7 +194,7 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       // breadcrumb still names the level: fall back to the single pane.
       setSelected(null)
     })
-  }, [listDirectory])
+  }, [launchListing])
 
   /** A right-column pick advances the view one level: child becomes the level. */
   const advance = useCallback((entry: DirectoryEntry) => {
@@ -196,12 +216,12 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       navigate()
       return
     }
-    requestSeq.current += 1
+    supersede()
     setError(null)
     setPathDraft(null)
     setFolderDraft(null)
     setCreateError(null)
-  }, [open, navigate])
+  }, [open, navigate, supersede])
 
   /** The folder a create or Open acts on: the selection, else the listed level. */
   const targetPath = selected?.path ?? parent?.path ?? null
@@ -227,9 +247,9 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       setFolderDraft(null)
       // Land like a right-column pick (figma 802:57446 → 813:23278 flow): the
       // create target becomes the listed level and the new folder its selection.
-      const seq = ++requestSeq.current
+      const { seq, scan } = launchListing(targetPath)
       setLoading(true)
-      listDirectory(targetPath).then((level) => {
+      scan.then((level) => {
         /* v8 ignore next -- same fence as navigate/select; the modal blocks superseding input */
         if (seq !== requestSeq.current) return
         setParent(level)
@@ -324,7 +344,7 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
                     // Opening the editor supersedes any pending listing: a
                     // settlement landing before the first keystroke would
                     // otherwise close the editor via navigate's draft reset.
-                    requestSeq.current += 1
+                    supersede()
                     setLoading(false)
                     setPathDraft(selected?.path ?? parent?.path ?? '')
                   }}
@@ -342,7 +362,7 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
                   // Editing the draft supersedes any in-flight navigation:
                   // its completion must neither clear the newer text nor
                   // repopulate the view with the older path.
-                  requestSeq.current += 1
+                  supersede()
                   setLoading(false)
                   setPathDraft(event.target.value)
                 }}
@@ -361,7 +381,7 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
                     // launched: its late success must not jump to the
                     // cancelled path, so the pending request is superseded
                     // and the view leaves the loading state.
-                    requestSeq.current += 1
+                    supersede()
                     setLoading(false)
                     setPathDraft(null)
                     setError(null)

packages/host/directory-picker-browse/src/client/flow.ts

@@ -13,8 +13,8 @@ import { DirectoryBrowser } from './DirectoryBrowser.tsx'
 
 /** Injected face: the browse wire calls and copy the dialog drives (bound in apply's closure). */
 export interface BrowseFlowInjected {
-  /** List one directory level (absent path = the Host home directory). */
-  listDirectory: (path?: string) => Promise<DirectoryListing>
+  /** List one directory level (absent path = the Host home directory); the signal aborts a superseded scan. */
+  listDirectory: (path?: string, signal?: AbortSignal) => Promise<DirectoryListing>
   /** Create one child directory under an existing parent. */
   createDirectory: (path: string, name: string) => Promise<string>
   /** Localized dialog copy (this package's namespace). */

packages/host/directory-picker-browse/src/client/index.ts

@@ -72,7 +72,7 @@ export function apply(ctx: ClientContext): void {
   }, 'directory-picker-browse: dialog dictionaries')
 
   const injected = (): BrowseFlowInjected => ({
-    listDirectory: path => ctx.workspaces.listDirectory(path),
+    listDirectory: (path, signal) => ctx.workspaces.listDirectory(path, signal),
     createDirectory: (path, name) => ctx.workspaces.createDirectory(path, name),
     t: ctx.locale.bind(LOCALE_NS),
   })

packages/host/directory-picker-browse/tests/directory-browser.spec.tsx

@@ -95,7 +95,7 @@ describe('DirectoryBrowser', () => {
   it('opens at the Host home as one wide column, hides hidden entries, and roots the crumbs at Home', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    expect(b.listDirectory).toHaveBeenCalledWith(undefined)
+    expect(b.listDirectory).toHaveBeenCalledWith(undefined, expect.any(AbortSignal))
     expect(columns()).toHaveLength(1)
     expect(screen.getByRole('listitem').textContent).toBe('Documents')
     expect(screen.queryByText('.config')).toBeNull()
@@ -113,7 +113,7 @@ describe('DirectoryBrowser', () => {
     expect(selectedRow.textContent).toBe('Documents')
     expect(rowButton(selectedRow).getAttribute('aria-current')).toBe('true')
     expect(within(preview!).getByRole('listitem').textContent).toBe('harness')
-    expect(b.listDirectory).toHaveBeenLastCalledWith(DOCS)
+    expect(b.listDirectory).toHaveBeenLastCalledWith(DOCS, expect.any(AbortSignal))
     expect(within(screen.getByRole('navigation')).getByRole('button', { name: 'Documents' })).toBeTruthy()
   })
 
@@ -130,6 +130,29 @@ describe('DirectoryBrowser', () => {
     expect(rowButton(selectedRow).getAttribute('aria-current')).toBe('true')
   })
 
+  it('aborts a superseded listing on the wire, and the in-flight one on close', async () => {
+    const signals: (AbortSignal | undefined)[] = []
+    const gates: (() => void)[] = []
+    const listDirectory = vi.fn((path?: string, signal?: AbortSignal) => {
+      signals.push(signal)
+      if (signals.length === 1) return Promise.resolve(listingFor(path))
+      // Later listings hang until released: supersession must abort them
+      // on the wire, not merely discard their eventual results.
+      return new Promise<DirectoryListing>((resolve) => { gates.push(() => { resolve(listingFor(path)) }) })
+    })
+    const b = mount({ listDirectory })
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(rowButton(screen.getByRole('listitem')))
+    expect(signals).toHaveLength(2)
+    // A crumb jump supersedes the hanging preview: its request aborts.
+    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
+    expect(signals[1]?.aborted).toBe(true)
+    expect(signals[2]?.aborted).toBe(false)
+    // Closing the dialog aborts the still-pending navigation too.
+    b.view.rerender(<DirectoryBrowser {...b.props} listDirectory={listDirectory} open={false} />)
+    expect(signals[2]?.aborted).toBe(true)
+  })
+
   it('jumps back through a crumb into a fresh single-column level', async () => {
     mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
@@ -195,7 +218,7 @@ describe('DirectoryBrowser', () => {
     // rows nor status behind.
     await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
     expect(listDirectory).toHaveBeenCalledTimes(2)
-    expect(listDirectory).toHaveBeenLastCalledWith(undefined)
+    expect(listDirectory).toHaveBeenLastCalledWith(undefined, expect.any(AbortSignal))
   })
 
   it('passes the entered path to the Host untrimmed (trim only gates blank drafts)', async () => {
@@ -207,7 +230,7 @@ describe('DirectoryBrowser', () => {
     fireEvent.change(input, { target: { value: `${DOCS} ` } })
     fireEvent.keyDown(input, { key: 'Enter' })
     // A trailing space may name a real directory; trimming would list its sibling.
-    await waitFor(() => { expect(listDirectory).toHaveBeenLastCalledWith(`${DOCS} `) })
+    await waitFor(() => { expect(listDirectory).toHaveBeenLastCalledWith(`${DOCS} `, expect.any(AbortSignal)) })
   })
 
   it('surfaces an unreadable target as an alert and keeps the edit open for correction', async () => {
@@ -347,7 +370,7 @@ describe('DirectoryBrowser', () => {
     expect(b.listDirectory.mock.calls.length).toBe(listCalls)
     fireEvent.compositionEnd(pathInput)
     fireEvent.keyDown(pathInput, { key: 'Enter' })
-    await waitFor(() => { expect(b.listDirectory).toHaveBeenLastCalledWith(DOCS) })
+    await waitFor(() => { expect(b.listDirectory).toHaveBeenLastCalledWith(DOCS, expect.any(AbortSignal)) })
     // Create dialog: same guard.
     fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
     const nameInput = screen.getByLabelText('browser.folderName')
@@ -764,6 +787,6 @@ describe('DirectoryBrowser', () => {
     b.view.rerender(<DirectoryBrowser {...b.props} open />)
     await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
     expect(columns()).toHaveLength(1)
-    expect(b.listDirectory).toHaveBeenLastCalledWith(undefined)
+    expect(b.listDirectory).toHaveBeenLastCalledWith(undefined, expect.any(AbortSignal))
   })
 })

pnpm-lock.yaml

@@ -215,6 +215,9 @@ importers:
       '@deepseek-ai/dsh-host-directory-picker-browse':
         specifier: workspace:^
         version: link:../../packages/host/directory-picker-browse
+      '@deepseek-ai/dsh-host-directory-picker-native':
+        specifier: workspace:^
+        version: link:../../packages/host/directory-picker-native
       '@deepseek-ai/dsh-host-webserver':
         specifier: workspace:^
         version: link:../../packages/host/webserver