FE-1097: Fix post-signup loop possibility

apps/hash-frontend/src/pages/_app.page.tsx

@@ -127,17 +127,28 @@ const App: FunctionComponent<AppProps> = ({
   const awaitingEmailVerificationStatus =
     !!authenticatedUser && !emailVerificationStatusKnown && !aal2Required;
 
+  /**
+   * A `redirectTo` that points at the page we're already on is a no-op we must
+   * ignore. `getInitialProps` re-runs on every navigation — including the
+   * same-URL `router.replace`s this effect performs — and `useRouter()` returns
+   * a fresh object each time, so honouring such a redirect spins forever in a
+   * `replace` -> `getInitialProps` -> `replace` loop (e.g. landing on `/` after
+   * accepting an org invite, where a stale `redirectTo: "/"` kept re-firing).
+   */
+  const pendingRedirect =
+    !!redirectTo && redirectTo !== router.asPath ? redirectTo : undefined;
+
   /**
    * Handle client-side redirects that were determined in getInitialProps.
    * On the server these are HTTP 307s; on the client getInitialProps returns
    * a `redirectTo` prop instead, and this effect performs the navigation after
    * the current route transition completes (avoiding NProgress stalls).
    */
   useEffect(() => {
-    if (redirectTo) {
-      void router.replace(redirectTo);
+    if (pendingRedirect) {
+      void router.replace(pendingRedirect);
     }
-  }, [redirectTo, router]);
+  }, [pendingRedirect, router]);
 
   useEffect(() => {
     setSentryUser({ authenticatedUser });
@@ -167,8 +178,15 @@ const App: FunctionComponent<AppProps> = ({
   // router.query is empty during server-side rendering for pages that don’t use
   // getServerSideProps. By showing app skeleton on the server, we avoid UI
   // mismatches during rehydration and improve type-safety of param extraction.
-  // We also gate on `redirectTo` so the page doesn't flash before navigating.
-  if (ssr || !router.isReady || awaitingEmailVerificationStatus || redirectTo) {
+  // We also gate on a pending redirect so the page doesn't flash before
+  // navigating. A `redirectTo` matching the current path isn't pending (see
+  // `pendingRedirect`), so we render rather than stall on the loading state.
+  if (
+    ssr ||
+    !router.isReady ||
+    awaitingEmailVerificationStatus ||
+    pendingRedirect
+  ) {
     return <Suspense />; // Replace with app skeleton
   }
 

apps/hash-frontend/src/pages/index.page.tsx

@@ -1,7 +1,7 @@
 import { useQuery } from "@apollo/client";
 import { Stack } from "@mui/material";
 import { useRouter } from "next/router";
-import { useMemo } from "react";
+import { useEffect, useMemo } from "react";
 
 import { hasAccessToHashQuery } from "../graphql/queries/user.queries";
 import { getLayoutWithSidebar } from "../shared/layout";
@@ -30,9 +30,20 @@ const Page: NextPageWithLayout = () => {
     }
   }, [authenticatedUser, hasAccessToHashResponse]);
 
+  const shouldCompleteSignup =
+    !authenticatedUser?.accountSignupComplete && !!hasAccessToHash;
+
+  /**
+   * Send users who have access but haven't finished signup to `/signup`.
+   */
+  useEffect(() => {
+    if (shouldCompleteSignup) {
+      void push("/signup");
+    }
+  }, [shouldCompleteSignup, push]);
+
   if (!authenticatedUser?.accountSignupComplete) {
     if (hasAccessToHash) {
-      void push("/signup");
       return null;
     }
 

apps/hash-frontend/src/pages/shared/auth-info-context.tsx

@@ -12,6 +12,7 @@ import {
 import {
   getOutgoingLinksForEntity,
   getRoots,
+  intervalCompareWithInterval,
   intervalForTimestamp,
 } from "@blockprotocol/graph/stdlib";
 import {
@@ -53,6 +54,29 @@ export const AuthInfoContext = createContext<AuthInfoContextValue | undefined>(
   undefined,
 );
 
+/**
+ * Returns `true` if `candidate` contains a newer edition of the user (by
+ * transaction time) than `existing`.
+ */
+const subgraphHasNewerUser = (
+  candidate: Subgraph<EntityRootType<HashEntity>>,
+  existing: Subgraph<EntityRootType<HashEntity>>,
+): boolean => {
+  const candidateUser = getRoots(candidate)[0];
+  const existingUser = getRoots(existing)[0];
+
+  if (!candidateUser || !existingUser) {
+    return true;
+  }
+
+  return (
+    intervalCompareWithInterval(
+      existingUser.metadata.temporalVersioning.transactionTime,
+      candidateUser.metadata.temporalVersioning.transactionTime,
+    ) < 0
+  );
+};
+
 type AuthInfoProviderProps = {
   initialAuthenticatedUserSubgraph?: Subgraph<EntityRootType<HashEntity>>;
   children: ReactElement;
@@ -72,6 +96,24 @@ export const AuthInfoProvider: FunctionComponent<AuthInfoProviderProps> = ({
   const [emailVerificationStatusKnown, setEmailVerificationStatusKnown] =
     useState(false);
 
+  /**
+   * `getInitialProps` re-fetches the authenticated user on every navigation and
+   * passes it as `initialAuthenticatedUserSubgraph`. Adopt that server-provided
+   * data whenever it is newer than what the client currently holds.
+   */
+  useEffect(() => {
+    if (!initialAuthenticatedUserSubgraph) {
+      return;
+    }
+
+    setAuthenticatedUserSubgraph((current) =>
+      !current ||
+      subgraphHasNewerUser(initialAuthenticatedUserSubgraph, current)
+        ? initialAuthenticatedUserSubgraph
+        : current,
+    );
+  }, [initialAuthenticatedUserSubgraph]);
+
   const userMemberOfLinks = useMemo(() => {
     if (!authenticatedUserSubgraph) {
       return undefined;

apps/hash-frontend/src/pages/shared/workspace-context.tsx

@@ -79,14 +79,17 @@ export const WorkspaceContextProvider: FunctionComponent<{
     }
   }, [activeWorkspaceWebId, updateActiveWorkspaceWebId, authenticatedUser]);
 
-  const workspaceContextValue = useMemo<WorkspaceContextValue>(() => {
-    const activeWorkspace =
+  const activeWorkspace = useMemo(
+    () =>
       authenticatedUser && authenticatedUser.accountId === activeWorkspaceWebId
         ? authenticatedUser
         : authenticatedUser?.memberOf.find(
             ({ org: { webId } }) => webId === activeWorkspaceWebId,
-          )?.org;
+          )?.org,
+    [authenticatedUser, activeWorkspaceWebId],
+  );
 
+  useEffect(() => {
     /**
      * If there is an `activeWorkspaceWebId` and an `authenticatedUser`, but
      * `activeWorkspace` is not defined, reset `activeWorkspaceWebId` to the
@@ -98,15 +101,22 @@ export const WorkspaceContextProvider: FunctionComponent<{
           (authenticatedUser.accountId as WebId),
       );
     }
+  }, [
+    activeWorkspace,
+    activeWorkspaceWebId,
+    authenticatedUser,
+    updateActiveWorkspaceWebId,
+  ]);
 
+  const workspaceContextValue = useMemo<WorkspaceContextValue>(() => {
     return {
       activeWorkspace,
       activeWorkspaceWebId,
       updateActiveWorkspaceWebId,
       refetchActiveWorkspace: () => refetch().then(() => undefined),
     };
   }, [
-    authenticatedUser,
+    activeWorkspace,
     activeWorkspaceWebId,
     updateActiveWorkspaceWebId,
     refetch,

apps/hash-frontend/src/pages/signup.page.tsx

@@ -242,7 +242,16 @@ const SignupPage: NextPageWithLayout = () => {
           refetchInvites();
           await refetchAuthenticatedUser();
           updateActiveWorkspaceWebId(invitation.org.webId);
-          void router.replace("/");
+          /**
+           * Hard navigation rather than `router.replace`: a client-side
+           * transition here can leave this component mounted on `/` (Next
+           * doesn't reliably re-resolve the route component on these
+           * `getInitialProps`-driven transitions). A full load guarantees a
+           * clean home render with fresh auth state.
+           *
+           * @todo sort out signup redirecting logic generally
+           */
+          window.location.assign("/");
           return;
         }
 
@@ -368,7 +377,16 @@ const SignupPage: NextPageWithLayout = () => {
         updateActiveWorkspaceWebId(invitation.org.webId);
       }
 
-      void router.push("/");
+      /**
+       * Hard navigation rather than `router.push`: a client-side transition
+       * here can leave this component mounted on `/` (Next doesn't reliably
+       * re-resolve the route component on these `getInitialProps`-driven
+       * transitions), stranding the user on a loading state. A full load
+       * guarantees a clean home render with fresh auth state.
+       *
+       * @todo sort out signup redirecting logic generally
+       */
+      window.location.assign("/");
     },
     [
       acceptInvitationOnce,
@@ -378,7 +396,6 @@ const SignupPage: NextPageWithLayout = () => {
       refetchAuthenticatedUser,
       updateAuthenticatedUser,
       updateActiveWorkspaceWebId,
-      router,
     ],
   );