fix(web): files panel and @ search follow the .code-workspace folder list

apps/web/src/components/ChatView.tsx

@@ -343,6 +343,8 @@ import { useEnvironmentDisconnectDelay } from "../hooks/useEnvironmentDisconnect
 import { selectThreadTerminalUiState, useTerminalUiStateStore } from "../terminalUiStateStore";
 import { useKnownTerminalSessions, useThreadRunningTerminalIds } from "../state/terminalSessions";
 import { useEnvironmentQuery } from "../state/query";
+import { filesystemEnvironment } from "../state/filesystem";
+import { resolveProjectFileRoots } from "../lib/projectFileRoots";
 import { vcsEnvironment } from "../state/vcs";
 import {
   environmentServerConfigsAtom,
@@ -3671,11 +3673,26 @@ export default function ChatView(props: ChatViewProps) {
           : null,
     [multiRepoStatusRoots, gitStatusCwd],
   );
-  // @-mention file search spans every repo root for a multi-repo workspace
-  // (#923); single-repo projects search the worktree-aware `gitCwd` alone.
-  const mentionRoots = useMemo(
-    () => (isMultiRepo ? (activeProject?.repoRoots ?? null) : null),
-    [isMultiRepo, activeProject?.repoRoots],
+  // The files panel and @-mention search span the folders a `.code-workspace`
+  // lists, while git surfaces stay on `repoRoots`. Null searches the
+  // worktree-aware cwd alone.
+  const workspaceFileQuery = useEnvironmentQuery(
+    projectWorkspaceFile === null
+      ? null
+      : filesystemEnvironment.readWorkspaceFile({
+          environmentId,
+          input: { workspaceFilePath: projectWorkspaceFile },
+        }),
+  );
+  const workspaceFolders = workspaceFileQuery.data?.folders ?? null;
+  const projectFileRoots = useMemo(
+    () =>
+      resolveProjectFileRoots({
+        workspaceFolders,
+        repoRoots: activeProject?.repoRoots,
+        worktrees: threadWorktrees,
+      }),
+    [workspaceFolders, activeProject?.repoRoots, threadWorktrees],
   );
   // Single-repo git query scoped to the anchor root, backing the branch-sync,
   // PR-checkout, and refresh flows; the multi-repo status/diff surfaces use
@@ -9769,7 +9786,7 @@ export default function ChatView(props: ChatViewProps) {
           composerDraftTarget={composerDraftTarget}
           keybindings={keybindings}
           availableEditors={availableEditors}
-          repoRoots={isMultiRepo ? (activeProject?.repoRoots ?? undefined) : undefined}
+          roots={projectFileRoots ?? undefined}
           relativePath={
             renderedRightPanelSurface.kind === "file"
               ? renderedRightPanelSurface.relativePath
@@ -10196,7 +10213,7 @@ export default function ChatView(props: ChatViewProps) {
                             timelineOverflows={timelineOverflows}
                             onComposerOverlayHeightChange={publishComposerOverlayHeight}
                             onRestingChange={onComposerRestingChange}
-                            mentionRoots={mentionRoots}
+                            mentionRoots={projectFileRoots}
                             promptRef={promptRef}
                             composerImagesRef={composerImagesRef}
                             composerFilesRef={composerFilesRef}

apps/web/src/components/ProjectFoldersDialog.tsx

@@ -93,8 +93,12 @@ export function ProjectFoldersDialog({
   // Filesystem RPCs are driven through the environment atoms (the old imperative
   // `readEnvironmentApi().filesystem.*` accessor was removed). Reads run via a
   // query runner; the write goes through the command atom and re-resolves the file.
+  // Refresh rather than reuse the cached read: the chat view keeps it alive for
+  // its files panel, so a stale entry would outlive both an edit made in VS Code
+  // and a save from this dialog.
   const readWorkspaceFile = useAtomQueryRunner(filesystemEnvironment.readWorkspaceFile, {
     reportFailure: false,
+    refresh: true,
   });
   const writeWorkspaceFile = useAtomCommand(filesystemEnvironment.writeWorkspaceFile, {
     reportFailure: false,
@@ -225,6 +229,10 @@ export function ProjectFoldersDialog({
           repoRoots: resolved.repoRoots,
         },
       });
+      void readWorkspaceFile({
+        environmentId: target.environmentId,
+        input: { workspaceFilePath: workspaceFile },
+      });
       const missing = resolved.folders.filter((folder) => !folder.exists);
       if (missing.length > 0) {
         toastManager.add({
@@ -247,7 +255,15 @@ export function ProjectFoldersDialog({
     } finally {
       setSaving(false);
     }
-  }, [folders, onClose, target, updateProject, workspaceFile, writeWorkspaceFile]);
+  }, [
+    folders,
+    onClose,
+    readWorkspaceFile,
+    target,
+    updateProject,
+    workspaceFile,
+    writeWorkspaceFile,
+  ]);
 
   return (
     <Dialog

apps/web/src/components/chat/ChatComposer.tsx

@@ -4,6 +4,8 @@ import { usePrimaryEnvironmentId } from "../../state/environments";
 import { runtimeModeConfig, runtimeModeOptions } from "./runtimeModeConfig";
 import { useRightPanelStore } from "~/rightPanelStore";
 import { AttachmentFilePreview } from "../files/AttachmentFilePreview";
+import { labelForRoot } from "../files/filePath";
+import { type ProjectFileRoot } from "../../lib/projectFileRoots";
 import { Dialog, DialogPopup, DialogTitle } from "../ui/dialog";
 import { filterComposerPullRequestMatches } from "@t3tools/shared/composerPullRequestMatches";
 import { importPastedComposerText, readPastedComposerContext } from "../composerInlineTokenPaste";
@@ -1428,9 +1430,9 @@ export interface ChatComposerProps {
    * effect, so it is current before the chat view measures the overlay.
    */
   onRestingChange: (resting: boolean) => void;
-  // Multi-repo workspaces (#923): roots to union for @-mention file search.
-  // Omitted/`null` for single-repo projects, which search `gitCwd` alone.
-  mentionRoots: ReadonlyArray<string> | null;
+  // Multi-root projects (#923): roots to union for @-mention file search, with
+  // the label each result is described under. `null` searches `gitCwd` alone.
+  mentionRoots: ReadonlyArray<ProjectFileRoot> | null;
 
   // Refs the parent needs kept in sync
   promptRef: React.RefObject<string>;
@@ -2268,10 +2270,18 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
   const settledPullRequestTextQuery =
     pullRequestTextQuery === debouncedPullRequestTextQuery ? pullRequestTextQuery : null;
   const isPathTrigger = composerTriggerKind === "path";
+  const mentionRootPaths = useMemo(
+    () => mentionRoots?.map(({ root }) => root) ?? null,
+    [mentionRoots],
+  );
+  const mentionRootLabels = useMemo(
+    () => new Map(mentionRoots?.map(({ root, label }) => [root, label])),
+    [mentionRoots],
+  );
   const workspaceEntries = useComposerPathSearch({
     environmentId,
     cwd: isPathTrigger ? gitCwd : null,
-    roots: isPathTrigger ? mentionRoots : null,
+    roots: isPathTrigger ? mentionRootPaths : null,
     query: isPathTrigger ? pathTriggerQuery : null,
   });
   const compactSlashCommandAvailable =
@@ -2360,7 +2370,10 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
         ...(entry.root ? { root: entry.root } : {}),
         label: basenameOfPath(entry.path),
         description: entry.root
-          ? `${basenameOfPath(entry.root)}/${entry.parentPath ?? ""}`.replace(/\/$/, "")
+          ? `${labelForRoot(mentionRootLabels, entry.root) ?? basenameOfPath(entry.root)}/${entry.parentPath ?? ""}`.replace(
+              /\/$/,
+              "",
+            )
           : (entry.parentPath ?? entry.path.slice(0, Math.max(0, entry.path.lastIndexOf("/")))),
       }));
     }
@@ -2497,6 +2510,7 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
     compactSlashCommandAvailable,
     composerTrigger,
     exactPullRequestLookup.data,
+    mentionRootLabels,
     planModeUiEnabled,
     pullRequestLookup.data,
     pullRequestProjectId,

apps/web/src/components/files/FileBreadcrumbs.tsx

@@ -18,11 +18,11 @@ import {
 import { Tooltip, TooltipPopup, TooltipTrigger } from "~/components/ui/tooltip";
 import { useTheme } from "~/hooks/useTheme";
 import { useWorkspaceMutationRefresh } from "~/hooks/useWorkspaceMutationRefresh";
+import { type ProjectFileRoot } from "~/lib/projectFileRoots";
 import { cn } from "~/lib/utils";
 import { isAbsolutePath } from "~/terminal-links";
 
 import {
-  buildRootLabels,
   type FileBreadcrumb,
   fileBreadcrumbChildren,
   fileBreadcrumbParent,
@@ -37,8 +37,8 @@ interface FileBreadcrumbsProps {
   readonly onOpenFile: (relativePath: string, root?: string) => void;
   readonly projectName: string;
   readonly relativePath: string;
-  /** Every repo root of a multi-repo project, so the repo crumb matches its file tree label. */
-  readonly repoRoots?: readonly string[] | undefined;
+  /** Every root of a multi-root project, so the root crumb matches its file tree label. */
+  readonly roots?: readonly ProjectFileRoot[] | undefined;
   /** Repo root that `relativePath` is relative to, when it is not `cwd` (multi-repo). */
   readonly root?: string | undefined;
   readonly workspaceMutationId: string | null;
@@ -276,14 +276,14 @@ export function FileBreadcrumbs(props: FileBreadcrumbsProps) {
   // A file in another repo of a multi-repo project reads "project > repo > path",
   // and every crumb from the repo down browses and opens within that repo.
   const repoRoot = props.root && props.root !== props.cwd ? props.root : undefined;
-  const repoRootsKey = props.repoRoots?.join("\0") ?? "";
+  const roots = props.roots;
   const repoName = useMemo(() => {
     if (!repoRoot) return undefined;
-    const label = repoRootsKey
-      ? labelForRoot(buildRootLabels(repoRootsKey.split("\0")), repoRoot)
+    const label = roots
+      ? labelForRoot(new Map(roots.map(({ root, label }) => [root, label])), repoRoot)
       : undefined;
     return label ?? repoRoot.split(/[\\/]/).findLast(Boolean) ?? repoRoot;
-  }, [repoRoot, repoRootsKey]);
+  }, [repoRoot, roots]);
   const breadcrumbs = useMemo(
     () =>
       repoName === undefined

apps/web/src/components/files/FileBrowserPanel.tsx

@@ -22,7 +22,8 @@ import { readLocalApi } from "~/localApi";
 import { T3_PIERRE_ICONS } from "~/pierre-icons";
 import { PIERRE_TREE_UNSAFE_CSS, pierreTreeStyle } from "~/pierre-tree-theme";
 
-import { buildRootLabels, isRootPath, labelForRoot } from "./filePath";
+import { isRootPath, labelForRoot } from "./filePath";
+import { type ProjectFileRoot, projectFileRootsKey } from "~/lib/projectFileRoots";
 import { createFileTreeDragMentionController } from "./fileTreeDragMention";
 import { areAllDirectoriesExpanded, setAllDirectoriesExpanded } from "./fileTreeExpansion";
 import { buildFileTreePathUpdates } from "./fileTreePathReconciliation";
@@ -39,9 +40,10 @@ interface FileBrowserPanelProps {
   selectedRoot?: string | undefined;
   /** Bumped when the same path should be revealed again (e.g. re-opened from search). */
   selectedPathRevealId: number;
-  // Multi-repo workspaces (#923): when set, list the union of these repo roots
-  // and group the tree by repo. Omitted/single-entry keeps single-root behavior.
-  repoRoots?: readonly string[] | undefined;
+  // Multi-root projects (#923): when set, list the union of these roots (repos,
+  // or the folders a `.code-workspace` lists) and group the tree by root.
+  // Omitted/single-entry keeps single-root behavior.
+  roots?: readonly ProjectFileRoot[] | undefined;
   onOpenFile: (relativePath: string, root?: string) => void;
   onRefreshSelectedFile?: () => void;
   workspaceMutationId: string | null;
@@ -112,7 +114,7 @@ export default function FileBrowserPanel({
   selectedPath: selectedRelativePath,
   selectedRoot,
   selectedPathRevealId,
-  repoRoots,
+  roots,
   onOpenFile,
   onRefreshSelectedFile,
   workspaceMutationId,
@@ -123,18 +125,20 @@ export default function FileBrowserPanel({
   // Multi-repo workspaces (#923): each repo is a top-level node named by its
   // label, and every tree path below it is prefixed with that label so
   // same-named files across repos don't collide.
-  const multiRepoRootsKey = repoRoots && repoRoots.length > 1 ? repoRoots.join("\0") : "";
+  const multiRootsKey = roots && roots.length > 1 ? projectFileRootsKey(roots) : "";
   const { rootLabels, directoryRoots, searchRoots } = useMemo(() => {
-    if (!multiRepoRootsKey)
+    if (!multiRootsKey)
       return { rootLabels: null, directoryRoots: undefined, searchRoots: undefined };
-    const roots = multiRepoRootsKey.split("\0");
-    const rootLabels = buildRootLabels(roots);
+    const directoryRoots = multiRootsKey.split("\0\0").map((pair) => {
+      const [label = "", root = ""] = pair.split("\0");
+      return { root, label };
+    });
     return {
-      rootLabels,
-      directoryRoots: roots.map((root) => ({ root, label: rootLabels.get(root) ?? root })),
-      searchRoots: roots,
+      rootLabels: new Map(directoryRoots.map(({ root, label }) => [root, label])),
+      directoryRoots,
+      searchRoots: directoryRoots.map(({ root }) => root),
     };
-  }, [multiRepoRootsKey]);
+  }, [multiRootsKey]);
   // Tree paths sit under their repo's label, so an open from outside the tree
   // (a chat link, the file picker) maps onto that key to be found and revealed.
   // A repo root linked by its absolute path selects that repo's top-level node.

apps/web/src/components/files/FilePreviewPanel.tsx

@@ -58,6 +58,7 @@ import FileBrowserPanel from "./FileBrowserPanel";
 import { FileBreadcrumbs } from "./FileBreadcrumbs";
 import { FileMarkdownPreview } from "./FileMarkdownPreview";
 import { isRootPath } from "./filePath";
+import { type ProjectFileRoot, projectFileRootsKey } from "~/lib/projectFileRoots";
 import {
   type FileCommentAnnotationEntry,
   type FileCommentAnnotationGroup,
@@ -104,8 +105,8 @@ interface FilePreviewPanelProps {
   availableEditors: ReadonlyArray<EditorId>;
   revealLine: number | null;
   revealRequestId: number;
-  // Multi-repo workspaces (#923): repo roots to list/group in the file tree.
-  repoRoots?: readonly string[] | undefined;
+  // Multi-root projects (#923): roots to list/group in the file tree.
+  roots?: readonly ProjectFileRoot[] | undefined;
   // Owning root of the currently-open file. Reads/writes resolve against this
   // root (it may be a different repo than the anchor `cwd`). Null = anchor.
   fileRoot?: string | null | undefined;
@@ -927,7 +928,7 @@ export default function FilePreviewPanel({
   availableEditors,
   revealLine,
   revealRequestId,
-  repoRoots,
+  roots,
   fileRoot,
   onOpenFile,
   onPendingChange,
@@ -971,7 +972,8 @@ export default function FilePreviewPanel({
   const isDirectory =
     file.isNotFile &&
     (!isHostFile ||
-      (relativePath !== null && isRootPath([cwd, ...(repoRoots ?? [])], relativePath)));
+      (relativePath !== null &&
+        isRootPath([cwd, ...(roots?.map(({ root }) => root) ?? [])], relativePath)));
   // Everything preview-related keys off previewPath; a folder has no preview.
   const previewPath = isDirectory ? null : relativePath;
   const [explorerOpen, setExplorerOpen] = useState(initialExplorerOpen);
@@ -1124,7 +1126,7 @@ export default function FilePreviewPanel({
                 onOpenFile={onOpenFile}
                 projectName={projectName}
                 relativePath={relativePath}
-                repoRoots={repoRoots}
+                roots={roots}
                 root={fileRoot ?? undefined}
                 workspaceMutationId={workspaceMutationId}
               />
@@ -1316,15 +1318,17 @@ export default function FilePreviewPanel({
                 : "min-w-0 flex-1",
             )}
           >
+            {/* The tree caches folders by label, so a root that changes path under
+                the same label must remount it rather than show the old contents. */}
             <FileBrowserPanel
-              key={`${environmentId}:${cwd}`}
+              key={`${environmentId}:${cwd}:${projectFileRootsKey(roots)}`}
               environmentId={environmentId}
               cwd={cwd}
               projectName={projectName}
               selectedPath={relativePath}
               selectedRoot={fileRoot ?? undefined}
               selectedPathRevealId={revealRequestId}
-              repoRoots={repoRoots}
+              roots={roots}
               onOpenFile={onOpenFile}
               workspaceMutationId={workspaceMutationId}
               {...(previewPath && !isMedia && !isPdf