A tag that throws at sign-up never keeps the new account on the page

The account exists before its completion is stated, so track() runs inside a
try: a throwing pixel is logged, and the browser still leaves for the app that
asked.

Co-authored-by: Hanzo Dev <[email protected]>

apps/web/src/pages/Signup.track.test.tsx

@@ -0,0 +1,67 @@
+/**
+ * The account exists before the completion is stated, so stating it can never
+ * be what keeps the person on this page: a tag that throws inside `track()`
+ * (a broken vendor build, an extension's shim) still lets the browser leave for
+ * the app that asked.
+ */
+import { afterEach, test, vi } from 'vitest'
+import assert from 'node:assert/strict'
+import { act, cleanup, fireEvent, render, waitFor } from '@testing-library/react'
+import type { Brand } from '@hanzo/id-shared'
+import { createAuthClient } from '@hanzo/id-auth'
+import { Signup } from './Signup'
+
+vi.mock('@hanzo/event', async (actual) => ({
+  ...(await actual<typeof import('@hanzo/event')>()),
+  track: () => {
+    throw new Error('pixel threw')
+  },
+}))
+
+afterEach(cleanup)
+
+const ORG = {
+  orgId: 'hanzo',
+  iamUrl: 'https://hanzo.id',
+  iamIssuer: 'https://hanzo.id',
+  clientId: 'hanzo-console',
+  appName: 'hanzo-console',
+  publicOrigin: 'https://hanzo.id',
+  brandPackage: '@hanzo/brand',
+} as Parameters<typeof createAuthClient>[0]['org']
+
+const BRAND = { name: 'Hanzo', logoUrl: '', faviconUrl: '' } as unknown as Brand
+const REDIRECT = 'https://hanzo.ai/auth/callback'
+
+/** IAM registers the account and mints the code the app asked for. */
+const iam = (async (input: RequestInfo | URL) => {
+  const path = new URL(input.toString()).pathname
+  const body =
+    path === '/v1/iam/signup'
+      ? { status: 'ok', data: { id: 'u-1', owner: 'hanzo', name: 'ada' } }
+      : path === '/v1/iam/login'
+        ? { status: 'ok', data: 'c-minted' }
+        : { status: 'ok', data: { enableSignUp: true } }
+  return new Response(JSON.stringify(body), { status: 200, headers: { 'Content-Type': 'application/json' } })
+}) as unknown as typeof fetch
+
+test('a tag that throws at completion does not keep the new account on this page', async () => {
+  const request = new URLSearchParams({ client_id: 'hanzo-app', redirect_uri: REDIRECT, response_type: 'code', state: 'S' })
+  ;(window as unknown as { happyDOM: { setURL(u: string): void } }).happyDOM.setURL(`https://hanzo.id/signup?${request}`)
+  const here = window.location.href
+  const gone: string[] = []
+  Object.defineProperty(window.location, 'href', { configurable: true, get: () => here, set: (u: string) => void gone.push(u) })
+  vi.spyOn(console, 'error').mockImplementation(() => {})
+
+  const { container } = render(<Signup client={createAuthClient({ org: ORG, fetchImpl: iam })} brand={BRAND} />)
+  await waitFor(() => assert.ok(container.querySelector('input[type=password]')))
+  await act(async () => {
+    fireEvent.change(container.querySelector('input[type=email]')!, { target: { value: '[email protected]' } })
+    fireEvent.change(container.querySelector('input[type=password]')!, { target: { value: 'correct horse battery staple' } })
+  })
+  await act(async () => void fireEvent.click(container.querySelector('button[type=submit]')!))
+
+  await waitFor(() => assert.equal(gone.length, 1, 'the browser leaves for the app'))
+  assert.ok(gone[0]!.startsWith(REDIRECT), `to the app that asked, got ${gone[0]}`)
+  assert.equal(container.querySelector('[role=alert]')?.textContent ?? '', '', 'and no error is shown')
+})

apps/web/src/pages/Signup.tsx

@@ -162,8 +162,14 @@ export function Signup({ client, brand }: { client: AuthClient; brand: Brand })
               if (subject) analytics.identify(subject)
               // ONE moment, under one event id, to our stream and to each of the
               // brand's tags the visitor's choice allows (GA4 `sign_up`, Meta
-              // `CompleteRegistration`), so no platform counts it twice.
-              track(analytics, EVENTS.SIGNUP_COMPLETED, { method: 'email' })
+              // `CompleteRegistration`), so no platform counts it twice. The
+              // account exists already and the browser leaves for it next, so a
+              // tag that throws here must not keep it on this page.
+              try {
+                track(analytics, EVENTS.SIGNUP_COMPLETED, { method: 'email' })
+              } catch (err) {
+                console.error('[event] signup_completed was not stated', err)
+              }
               // The browser leaves for the app on the next line, so the whole
               // buffer goes now rather than waiting on the flush timer.
               analytics.flush(true)