Paid cloud downloads paid with Minibits ecash were always rejected. The
buyer sends a cashuB token, which carries NUT-02 v2 keyset ids in their
8-byte short form. Minibits rotated its active keyset to a v2 id, and the
seller's verify_and_receive_payment called MintClient::swap directly,
skipping the short->full id repair that only receive_token applied. The
mint answered 422 ("ID length invalid"). The buyer then showed the
misleading "seller doesn't accept your Cashu mint" hint.
Move the repair into swap() so every caller is covered: payment verify,
streaming gate, send change, and cross-mint swaps.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ssmithxandClaude Opus 5.5
8b74803290