Fix Discord linking error handling and section routing issues

- Reset linkingDiscord state and show error message when linkSocial throws,
  so users can retry if the OAuth flow fails
- Move VALID_SECTION_IDS to module level and derive it from SECTIONS to
  avoid per-render allocation and prevent the two from drifting out of sync
- Remove premature SectionId cast before the allowlist validation in
  the ?section= URL param handling
- Add tests for loading state and error recovery in AccountSection

Fixes #455

https://claude.ai/code/session_01UerTpTuBWjreTNEns8srkp

app/components/user/settings/AccountSection.tsx

@@ -22,13 +22,20 @@ const PROVIDER_LABELS: Record<string, string> = {
 
 export function AccountSection({ email, linkedAccounts }: Props) {
   const [linkingDiscord, setLinkingDiscord] = useState(false);
+  const [linkError, setLinkError] = useState<string | null>(null);
   const hasPassword = linkedAccounts.some((a) => a.providerId === "credential");
   const oauthAccounts = linkedAccounts.filter((a) => a.providerId !== "credential");
   const hasDiscord = linkedAccounts.some((a) => a.providerId === "discord");
 
   async function handleConnectDiscord() {
     setLinkingDiscord(true);
-    await authClient.linkSocial({ provider: "discord", callbackURL: "/settings?section=account" });
+    setLinkError(null);
+    try {
+      await authClient.linkSocial({ provider: "discord", callbackURL: "/settings?section=account" });
+    } catch {
+      setLinkError("Failed to connect Discord. Please try again.");
+      setLinkingDiscord(false);
+    }
   }
 
   return (
@@ -68,14 +75,19 @@ export function AccountSection({ email, linkedAccounts }: Props) {
             )}
           </div>
           {!hasDiscord && (
-            <Button
-              variant="outline"
-              size="sm"
-              onClick={handleConnectDiscord}
-              disabled={linkingDiscord}
-            >
-              {linkingDiscord ? "Redirecting…" : "Connect Discord"}
-            </Button>
+            <div className="space-y-2">
+              <Button
+                variant="outline"
+                size="sm"
+                onClick={handleConnectDiscord}
+                disabled={linkingDiscord}
+              >
+                {linkingDiscord ? "Redirecting…" : "Connect Discord"}
+              </Button>
+              {linkError && (
+                <p className="text-sm text-destructive">{linkError}</p>
+              )}
+            </div>
           )}
         </div>
 

app/components/user/settings/__tests__/AccountSection.test.tsx

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
-import { render, screen, fireEvent } from "@testing-library/react";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
 import { AccountSection } from "../AccountSection";
 
 vi.mock("react-router", () => ({
@@ -44,7 +44,7 @@ describe("AccountSection", () => {
     expect(screen.queryByRole("button", { name: /connect discord/i })).not.toBeInTheDocument();
   });
 
-  it("calls authClient.linkSocial with discord provider on button click", () => {
+  it("calls authClient.linkSocial with discord provider on button click", async () => {
     render(
       <AccountSection
         email="user@example.com"
@@ -52,9 +52,42 @@ describe("AccountSection", () => {
       />
     );
     fireEvent.click(screen.getByRole("button", { name: /connect discord/i }));
-    expect(mockLinkSocial).toHaveBeenCalledWith({
-      provider: "discord",
-      callbackURL: "/settings?section=account",
+    await waitFor(() => {
+      expect(mockLinkSocial).toHaveBeenCalledWith({
+        provider: "discord",
+        callbackURL: "/settings?section=account",
+      });
+    });
+  });
+
+  it("shows Redirecting… and disables the button while linking", async () => {
+    // Never resolves so we can inspect the in-flight state
+    mockLinkSocial.mockReturnValue(new Promise(() => {}));
+    render(
+      <AccountSection
+        email="user@example.com"
+        linkedAccounts={[{ id: "1", providerId: "credential" }]}
+      />
+    );
+    fireEvent.click(screen.getByRole("button", { name: /connect discord/i }));
+    await waitFor(() => {
+      const btn = screen.getByRole("button", { name: /redirecting/i });
+      expect(btn).toBeDisabled();
+    });
+  });
+
+  it("re-enables the button and shows an error message when linkSocial throws", async () => {
+    mockLinkSocial.mockRejectedValue(new Error("OAuth failed"));
+    render(
+      <AccountSection
+        email="user@example.com"
+        linkedAccounts={[{ id: "1", providerId: "credential" }]}
+      />
+    );
+    fireEvent.click(screen.getByRole("button", { name: /connect discord/i }));
+    await waitFor(() => {
+      expect(screen.getByRole("button", { name: /connect discord/i })).not.toBeDisabled();
+      expect(screen.getByText(/failed to connect discord/i)).toBeInTheDocument();
     });
   });
 });

app/routes/settings.tsx

@@ -35,6 +35,7 @@ const SECTIONS: readonly SettingsGridSection[] = [
 ] as const;
 
 const VALID_TIMEZONES = new Set(TIMEZONE_OPTIONS.flatMap((g) => g.zones.map((z) => z.value)));
+const VALID_SECTION_IDS = new Set(SECTIONS.map((s) => s.id as SectionId));
 
 const DATA_REQUEST_COOLDOWN_MS = 30 * 24 * 60 * 60 * 1000; // 30 days
 
@@ -207,9 +208,8 @@ export async function action(args: Route.ActionArgs): Promise<ActionData | Respo
 export default function SettingsPage({ loaderData, actionData }: Route.ComponentProps) {
   const { user, isInActiveDraft, linkedAccounts, dataRequestCooldownUntil } = loaderData;
   const [searchParams] = useSearchParams();
-  const VALID_SECTION_IDS = new Set<SectionId>(["profile", "account", "notifications", "api", "privacy"]);
-  const sectionParam = searchParams.get("section") as SectionId | null;
-  const initialSection: SectionId = sectionParam && VALID_SECTION_IDS.has(sectionParam) ? sectionParam : "profile";
+  const raw = searchParams.get("section");
+  const initialSection: SectionId = raw && (VALID_SECTION_IDS as Set<string>).has(raw) ? (raw as SectionId) : "profile";
   const [activeSection, setActiveSection] = useState<SectionId>(initialSection);
   const [mobileView, setMobileView] = useState<"grid" | "section">("grid");