Mail login: empty ?wallet= bypasses DFX Wallet default (follow-up to #1161)

[marassteiner]

EN: Empty ?wallet= is forwarded as '' and therefore skips the new DFX Wallet default on mail login.
DE: Ein leeres ?wallet= wird als '' weitergereicht und umgeht damit den neuen DFX-Wallet-Default beim Mail-Login.

Details

Context

Follow-up from review of #1161 (head f64d21e5).

The mail-login default uses nullish coalescing:

// src/components/home/wallet/connect-mail.tsx:70
signInWithMail(mail, redirectUri, recommendationCode, wallet ?? DFX_WALLET_NAME)

?? treats only null/undefined as missing. An empty URL param is preserved as '' and sent to POST /v1/auth/mail unchanged.

Evidence

• src/components/home/wallet/connect-mail.tsx:70 — wallet ?? DFX_WALLET_NAME
• src/contexts/app-handling.context.tsx:255 — getParameter is query.get(key) ?? undefined, so ?wallet= stays ''
• src/contexts/app-handling.context.tsx:358 — that value is stored as wallet
• src/__tests__/connect-mail-redirect.test.tsx:155 and :174 cover undefined and 'RealUnit', not ''

This is a pre-existing empty-param path. The PR did not introduce it; it only added a default for absent params. It is not a merge blocker for #1161 — the stated contract is that an explicit ?wallet= is forwarded (??).

Suggested fix

If empty should count as missing:

signInWithMail(mail, redirectUri, recommendationCode, wallet || DFX_WALLET_NAME)

(or, if host-scoping from #1332 lands, only in that branch). Add a unit case with { wallet: '' }.

If empty should stay explicit, no code change — just add the test so the ?? contract is locked in.

Related

• PR: feat(auth): tag DFX Wallet on app.dfx.swiss email logins #1161
• Host-scope follow-up: Host-scope DFX wallet default on mail login (follow-up to #1161) #1332