Preserve workspace diff stats across rehydration

packages/app/src/contexts/session-context.tsx

@@ -33,6 +33,7 @@ import {
   type Agent,
   type SessionState,
   type WorkspaceDescriptor,
+  mergeWorkspaceSnapshotWithExisting,
   normalizeWorkspaceDescriptor,
 } from "@/stores/session-store";
 import { useDraftStore } from "@/stores/draft-store";
@@ -326,6 +327,7 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
       }
 
       const workspaces = new Map<string, WorkspaceDescriptor>();
+      const existingWorkspaces = useSessionStore.getState().sessions[serverId]?.workspaces;
       let cursor: string | null = null;
       let includeSubscribe = options?.subscribe ?? false;
 
@@ -341,7 +343,13 @@ function SessionProviderInternal({ children, serverId, client }: SessionProvider
 
         for (const entry of payload.entries) {
           const workspace = normalizeWorkspaceDescriptor(entry);
-          workspaces.set(workspace.id, workspace);
+          workspaces.set(
+            workspace.id,
+            mergeWorkspaceSnapshotWithExisting({
+              incoming: workspace,
+              existing: existingWorkspaces?.get(workspace.id),
+            }),
+          );
         }
 
         if (!payload.pageInfo.hasMore || !payload.pageInfo.nextCursor) {

packages/app/src/hooks/use-sidebar-workspaces-list.ts

@@ -1,5 +1,9 @@
 import { useCallback, useEffect, useMemo, useSyncExternalStore } from "react";
-import { normalizeWorkspaceDescriptor, useSessionStore } from "@/stores/session-store";
+import {
+  mergeWorkspaceSnapshotWithExisting,
+  normalizeWorkspaceDescriptor,
+  useSessionStore,
+} from "@/stores/session-store";
 import { getHostRuntimeStore } from "@/runtime/host-runtime";
 import { useSidebarOrderStore } from "@/stores/sidebar-order-store";
 import type { WorkspaceDescriptor } from "@/stores/session-store";
@@ -356,6 +360,7 @@ export function useSidebarWorkspacesList(options?: {
     }
     void (async () => {
       const next = new Map<string, WorkspaceDescriptor>();
+      const existingWorkspaces = useSessionStore.getState().sessions[serverId]?.workspaces;
       let cursor: string | null = null;
       try {
         while (true) {
@@ -365,7 +370,13 @@ export function useSidebarWorkspacesList(options?: {
           });
           for (const entry of payload.entries) {
             const workspace = toWorkspaceDescriptor(entry);
-            next.set(workspace.id, workspace);
+            next.set(
+              workspace.id,
+              mergeWorkspaceSnapshotWithExisting({
+                incoming: workspace,
+                existing: existingWorkspaces?.get(workspace.id),
+              }),
+            );
           }
           if (!payload.pageInfo.hasMore || !payload.pageInfo.nextCursor) {
             break;

packages/app/src/stores/session-store.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import {
+  mergeWorkspaceSnapshotWithExisting,
+  type WorkspaceDescriptor,
+} from "./session-store";
+
+function createWorkspace(
+  input: Partial<WorkspaceDescriptor> & Pick<WorkspaceDescriptor, "id">,
+): WorkspaceDescriptor {
+  return {
+    id: input.id,
+    projectId: input.projectId ?? "remote:github.com/getpaseo/paseo",
+    projectDisplayName: input.projectDisplayName ?? "getpaseo/paseo",
+    projectRootPath: input.projectRootPath ?? "/tmp/repo",
+    projectKind: input.projectKind ?? "git",
+    workspaceKind: input.workspaceKind ?? "local_checkout",
+    name: input.name ?? "main",
+    status: input.status ?? "done",
+    activityAt: input.activityAt ?? null,
+    diffStat: input.diffStat ?? null,
+  };
+}
+
+describe("mergeWorkspaceSnapshotWithExisting", () => {
+  it("preserves the last known diff stat when a snapshot only has baseline null data", () => {
+    const existing = createWorkspace({
+      id: "/tmp/repo",
+      diffStat: { additions: 4, deletions: 2 },
+    });
+    const incoming = createWorkspace({
+      id: "/tmp/repo",
+      diffStat: null,
+    });
+
+    expect(mergeWorkspaceSnapshotWithExisting({ incoming, existing })).toEqual({
+      ...incoming,
+      diffStat: { additions: 4, deletions: 2 },
+    });
+  });
+
+  it("uses the incoming diff stat when the server provides a known value", () => {
+    const existing = createWorkspace({
+      id: "/tmp/repo",
+      diffStat: { additions: 4, deletions: 2 },
+    });
+    const incoming = createWorkspace({
+      id: "/tmp/repo",
+      diffStat: { additions: 0, deletions: 0 },
+    });
+
+    expect(mergeWorkspaceSnapshotWithExisting({ incoming, existing })).toEqual(incoming);
+  });
+});

packages/app/src/stores/session-store.ts

@@ -142,6 +142,21 @@ export function normalizeWorkspaceDescriptor(
   };
 }
 
+export function mergeWorkspaceSnapshotWithExisting(input: {
+  incoming: WorkspaceDescriptor;
+  existing?: WorkspaceDescriptor | null;
+}): WorkspaceDescriptor {
+  const { incoming, existing } = input;
+  if (!existing || existing.id !== incoming.id) {
+    return incoming;
+  }
+
+  return {
+    ...incoming,
+    diffStat: incoming.diffStat ?? existing.diffStat,
+  };
+}
+
 export type ExplorerEntryKind = "file" | "directory";
 export type ExplorerFileKind = "text" | "image" | "binary";
 export type ExplorerEncoding = "utf-8" | "base64" | "none";