From e2835ebd9261911e292d89471682e5264b98c1fd Mon Sep 17 00:00:00 2001
From: orveth <orveth@proton.me>
Date: Wed, 6 May 2026 10:33:04 -0700
Subject: [PATCH] fix(receive): show unsupported-unit page instead of crashing
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Content-Type: text/plain; charset=UTF-8
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Pasting or deep-linking a Cashu token whose unit isn't sat or usd
crashed /receive/cashu/token because tokenToMoney threw synchronously
inside render-path hooks.

The route loaders now run validateCashuToken right after decode and
short-circuit to UnsupportedCashuTokenPage with a reason-specific
message. Send flow is unaffected — internally-generated tokens always
have a supported unit derived from Currency. validateCashuToken
returns a discriminated union so future checks (empty proofs,
blocklisted mint, etc.) plug in as additional early-return branches.
---
 .../receive/unsupported-cashu-token-page.tsx  | 25 +++++++++++++++++++
 app/lib/cashu/utils.ts                        | 23 ++++++++++++++++-
 .../_protected.receive.cashu_.token.tsx       | 21 +++++++++++++---
 app/routes/_public.receive-cashu-token.tsx    | 19 +++++++++++---
 4 files changed, 80 insertions(+), 8 deletions(-)
 create mode 100644 app/features/receive/unsupported-cashu-token-page.tsx

diff --git a/app/features/receive/unsupported-cashu-token-page.tsx b/app/features/receive/unsupported-cashu-token-page.tsx
new file mode 100644
index 000000000..ad83fe538
--- /dev/null
+++ b/app/features/receive/unsupported-cashu-token-page.tsx
@@ -0,0 +1,25 @@
+import {
+  ClosePageButton,
+  Page,
+  PageContent,
+  PageHeader,
+  PageHeaderTitle,
+} from '~/components/page';
+
+type Props = {
+  message: string;
+};
+
+export function UnsupportedCashuTokenPage({ message }: Props) {
+  return (
+    <Page>
+      <PageHeader>
+        <ClosePageButton to="/" transition="slideDown" applyTo="oldView" />
+        <PageHeaderTitle>Oops!</PageHeaderTitle>
+      </PageHeader>
+      <PageContent className="flex flex-col items-center justify-center text-center">
+        <p>{message}</p>
+      </PageContent>
+    </Page>
+  );
+}
diff --git a/app/lib/cashu/utils.ts b/app/lib/cashu/utils.ts
index d353fdd6c..8b6db6204 100644
--- a/app/lib/cashu/utils.ts
+++ b/app/lib/cashu/utils.ts
@@ -9,6 +9,7 @@ import {
   Wallet,
   splitAmount,
 } from '@cashu/cashu-ts';
+import type { Token } from '@cashu/cashu-ts';
 import type { DistributedOmit } from 'type-fest';
 import type { Currency, CurrencyUnit } from '../money';
 import {
@@ -16,7 +17,7 @@ import {
   type ExtendedMintQuoteBolt11Response,
   type MintPurpose,
 } from './protocol-extensions';
-import type { CashuProtocolUnit } from './types';
+import { CASHU_PROTOCOL_UNITS, type CashuProtocolUnit } from './types';
 
 const knownTestMints = [
   'https://testnut.cashu.space',
@@ -73,6 +74,26 @@ export const getCashuProtocolUnit = (currency: Currency) => {
   return currencyToCashuProtocolUnit[currency];
 };
 
+export type CashuTokenValidation =
+  | { isTokenSupported: true }
+  | { isTokenSupported: false; message: string };
+
+/**
+ * Validates that a decoded Cashu token is one Agicash supports.
+ */
+export const validateCashuToken = (token: Token): CashuTokenValidation => {
+  if (
+    token.unit === undefined ||
+    !(token.unit in cashuProtocolUnitToCurrency)
+  ) {
+    return {
+      isTokenSupported: false,
+      message: `This token's unit isn't supported. Supported units: ${CASHU_PROTOCOL_UNITS.join(', ')}.`,
+    };
+  }
+  return { isTokenSupported: true };
+};
+
 /**
  * Determines the purpose of a mint based on its info.
  */
diff --git a/app/routes/_protected.receive.cashu_.token.tsx b/app/routes/_protected.receive.cashu_.token.tsx
index e9dde2c68..283b6a8fc 100644
--- a/app/routes/_protected.receive.cashu_.token.tsx
+++ b/app/routes/_protected.receive.cashu_.token.tsx
@@ -15,6 +15,7 @@ import { ReceiveCashuTokenQuoteService } from '~/features/receive/receive-cashu-
 import { ReceiveCashuTokenService } from '~/features/receive/receive-cashu-token-service';
 import { SparkReceiveQuoteRepository } from '~/features/receive/spark-receive-quote-repository';
 import { SparkReceiveQuoteService } from '~/features/receive/spark-receive-quote-service';
+import { UnsupportedCashuTokenPage } from '~/features/receive/unsupported-cashu-token-page';
 import {
   decodeCashuToken,
   getCashuCryptography,
@@ -31,6 +32,7 @@ import { getUserFromCacheOrThrow } from '~/features/user/user-hooks';
 import { WriteUserRepository } from '~/features/user/user-repository';
 import { UserService } from '~/features/user/user-service';
 import { toast } from '~/hooks/use-toast';
+import { validateCashuToken } from '~/lib/cashu';
 import type { Route } from './+types/_protected.receive.cashu_.token';
 import { ReceiveCashuTokenSkeleton } from './receive-cashu-token-skeleton';
 
@@ -114,6 +116,15 @@ export async function clientLoader({ request }: Route.ClientLoaderArgs) {
     throw redirect('/receive');
   }
 
+  const validation = validateCashuToken(token);
+
+  if (!validation.isTokenSupported) {
+    return {
+      isTokenSupported: false as const,
+      message: validation.message,
+    };
+  }
+
   const location = new URL(request.url);
   const selectedAccountId =
     location.searchParams.get('selectedAccountId') ?? undefined;
@@ -151,7 +162,7 @@ export async function clientLoader({ request }: Route.ClientLoaderArgs) {
     throw redirect(redirectTo);
   }
 
-  return { token, selectedAccountId };
+  return { isTokenSupported: true as const, token, selectedAccountId };
 }
 
 clientLoader.hydrate = true as const;
@@ -163,14 +174,16 @@ export function HydrateFallback() {
 export default function ProtectedReceiveCashuToken({
   loaderData,
 }: Route.ComponentProps) {
-  const { token, selectedAccountId } = loaderData;
+  if (!loaderData.isTokenSupported) {
+    return <UnsupportedCashuTokenPage message={loaderData.message} />;
+  }
 
   return (
     <Page>
       <Suspense fallback={<ReceiveCashuTokenSkeleton />}>
         <ReceiveCashuToken
-          token={token}
-          preferredReceiveAccountId={selectedAccountId}
+          token={loaderData.token}
+          preferredReceiveAccountId={loaderData.selectedAccountId}
         />
       </Suspense>
     </Page>
diff --git a/app/routes/_public.receive-cashu-token.tsx b/app/routes/_public.receive-cashu-token.tsx
index b0a999d2a..76062ede5 100644
--- a/app/routes/_public.receive-cashu-token.tsx
+++ b/app/routes/_public.receive-cashu-token.tsx
@@ -3,9 +3,11 @@ import { Page } from '~/components/page';
 import { getGiftCardByUrl } from '~/features/gift-cards/use-discover-cards';
 import { LoadingScreen } from '~/features/loading/LoadingScreen';
 import { PublicReceiveCashuToken } from '~/features/receive/receive-cashu-token';
+import { UnsupportedCashuTokenPage } from '~/features/receive/unsupported-cashu-token-page';
 import { decodeCashuToken } from '~/features/shared/cashu';
 import { getQueryClient } from '~/features/shared/query-client';
 import { authQueryOptions } from '~/features/user/auth';
+import { validateCashuToken } from '~/lib/cashu';
 import { normalizeMintUrl } from '~/lib/cashu/utils';
 import type { Route } from './+types/_public.receive-cashu-token';
 
@@ -88,7 +90,16 @@ export async function clientLoader({ request }: Route.ClientLoaderArgs) {
     throw redirect('/home');
   }
 
-  return { token };
+  const validation = validateCashuToken(token);
+
+  if (!validation.isTokenSupported) {
+    return {
+      isTokenSupported: false as const,
+      message: validation.message,
+    };
+  }
+
+  return { isTokenSupported: true as const, token };
 }
 
 clientLoader.hydrate = true as const;
@@ -100,11 +111,13 @@ export function HydrateFallback() {
 export default function ReceiveCashuTokenPage({
   loaderData,
 }: Route.ComponentProps) {
-  const { token } = loaderData;
+  if (!loaderData.isTokenSupported) {
+    return <UnsupportedCashuTokenPage message={loaderData.message} />;
+  }
 
   return (
     <Page>
-      <PublicReceiveCashuToken token={token} />
+      <PublicReceiveCashuToken token={loaderData.token} />
     </Page>
   );
 }