v4: a user from another instance can't be renamed from their profile's manage tab — it offered the name field to every user, and the API refuses a remote one's rename with a 400, since their home names them. The tab now only shows their name, as the settings do for one's own.

The profile's and the settings' tests of a remote account's links to its home still expected the home's host itself, which 8bcc005 replaced with GET /api/users/:key/home; they now expect that.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/components/profile/ProfileManageTab.tsx

@@ -13,6 +13,7 @@ import type { PublicUser } from "../../../shared/user.ts";
 import { expectOk } from "../../utils/shared/api.ts";
 import { deserializePublicUser } from "../../utils/shared/deserialize.ts";
 import { useAuth } from "../../hooks/auth/useAuth.ts";
+import { homeHost } from "../../utils/auth/home.ts";
 import { ProfileSection } from "./ProfileSection.tsx";
 import { RoleSwitcher } from "./RoleSwitcher.tsx";
 import { SettingRow } from "./SettingRow.tsx";
@@ -30,7 +31,8 @@ export interface ProfileManageTabProps {
 
 /**
  * Renders the user's role and name. A rename here has no rate limit, and the
- * profile's URL then takes the new name.
+ * profile's URL then takes the new name. A user from another instance is
+ * named there, so their name is only shown.
  */
 export function ProfileManageTab(
   { user, onUserSaved }: ProfileManageTabProps,
@@ -59,11 +61,15 @@ export function ProfileManageTab(
           onSaved={(role) => onUserSaved({ ...user, role })}
         />
         <SettingRow label={<Trans>Username</Trans>}>
-          <UsernameField
-            key={user.username}
-            username={user.username}
-            save={rename}
-          />
+          {homeHost(user.username)
+            ? <span className="profile-appearance-value">{user.username}</span>
+            : (
+              <UsernameField
+                key={user.username}
+                username={user.username}
+                save={rename}
+              />
+            )}
         </SettingRow>
       </div>
     </ProfileSection>

src/test/pages/Settings.test.tsx

@@ -7,6 +7,7 @@ import { calls, fail, route } from "../fetch.ts";
 import { makeSession, makeToken } from "../fixtures.ts";
 import { renderApp } from "../render.tsx";
 import { AUTH_STORAGE_KEY } from "../../utils/auth/storage.ts";
+import { API_URL } from "../../config/api.ts";
 
 const instance = vi.hoisted(() => ({
   emailEnabled: false,
@@ -217,9 +218,10 @@ describe("Settings", () => {
     const link = await screen.findByRole("link", {
       name: "Change it on home.example",
     });
+    // Through the API, which redirects to the home's pages.
     expect(link).toHaveAttribute(
       "href",
-      `${location.protocol}//home.example/settings`,
+      `${API_URL}/api/users/@alice%40home.example/home?path=%2Fsettings`,
     );
     expect(screen.queryByText("Other instances")).not.toBeInTheDocument();
     expect(calls("GET /api/me/grants")).toHaveLength(0);

src/test/pages/UserPublicProfile.test.tsx

@@ -1,3 +1,4 @@
+import { API_URL } from "../../config/api.ts";
 import { describe, expect, test, vi } from "vitest";
 import { act, screen, waitFor, within } from "@testing-library/react";
 import { userEvent } from "@testing-library/user-event";
@@ -65,9 +66,10 @@ describe("UserPublicProfile", () => {
     });
     expect(await screen.findByRole("heading", { name: "alice@home.example" }))
       .toBeInTheDocument();
+    // Through the API, which redirects to the home's pages.
     expect(screen.getByRole("link", { name: "home.example" })).toHaveAttribute(
       "href",
-      `${location.protocol}//home.example/@alice`,
+      `${API_URL}/api/users/@alice%40home.example/home`,
     );
     expect(screen.queryByTitle("Change avatar")).not.toBeInTheDocument();
     expect(screen.queryByTitle("Edit email")).not.toBeInTheDocument();
@@ -617,6 +619,20 @@ describe("UserPublicProfile", () => {
       );
     });
 
+    test("a user from another instance is named there, not here", async () => {
+      open({
+        session: makeSession({ id: "admin", role: "admin" }),
+        user: { ...ann, username: "ann@home.example" },
+        url: "/@ann@home.example/manage",
+      });
+      expect(
+        await screen.findByText("ann@home.example", {
+          selector: ".profile-appearance-value",
+        }),
+      ).toBeInTheDocument();
+      expect(screen.queryByRole("textbox", { name: "Username" })).toBeNull();
+    });
+
     test("non-admins get no manage tab, nor its page", async () => {
       open({
         session: makeSession({ id: "mod", role: "moderator" }),