fix(sp): mark silent payment coins spent elsewhere as spent

class/wallets/hd-bip352-wallet.ts

@@ -349,6 +349,35 @@ export class HDSilentPaymentsWallet extends HDTaprootWallet implements IScannabl
     return true;
   }
 
+  /**
+   * The indexer doesn't report spends, and markUTXOAsSpent only sees this device's own broadcasts,
+   * so a restored wallet would count SP coins spent long ago. Every SP output has its own taproot
+   * address, so ask Electrum: a coin it knows (funding tx in the address history) but no longer
+   * lists as unspent is spent. A coin Electrum hasn't seen yet is left alone.
+   */
+  private async markSpentSilentPaymentUTXOs(): Promise<void> {
+    const utxos = this.getUTXOs();
+    if (utxos.length === 0) return;
+
+    try {
+      const addresses = [...new Set(utxos.map(u => u.address))];
+      const [unspent, history] = await Promise.all([
+        Electrum.multiGetUtxoByAddress(addresses),
+        Electrum.multiGetHistoryByAddress(addresses),
+      ]);
+
+      for (const utxo of utxos) {
+        const known = history[utxo.address]?.some(h => h.tx_hash === utxo.txid);
+        const listed = unspent[utxo.address];
+        if (known && listed && !listed.some(u => u.txid === utxo.txid && u.vout === utxo.vout)) {
+          this.markUTXOAsSpent(utxo.txid, utxo.vout);
+        }
+      }
+    } catch (error) {
+      console.warn('[SP] Could not check SP coins for spends:', error);
+    }
+  }
+
   private ensurePendingInputsInitialized(): void {
     if (!this._sp_pending_inputs || !(this._sp_pending_inputs instanceof Set)) {
       this._sp_pending_inputs = new Set();
@@ -620,6 +649,7 @@ export class HDSilentPaymentsWallet extends HDTaprootWallet implements IScannabl
 
     try {
       const result = await this.activeScanPromise;
+      await this.markSpentSilentPaymentUTXOs();
       return result;
     } finally {
       this.activeScanPromise = null;

tests/unit/sp-spent-check.test.ts

@@ -0,0 +1,55 @@
+import * as Electrum from '../../modules/Electrum';
+import { HDSilentPaymentsWallet } from '../../class/wallets/hd-bip352-wallet.ts';
+import { type SilentPaymentUTXO } from '../../helpers/silent-payments/types.ts';
+
+jest.mock('../../modules/Electrum', () => ({
+  multiGetUtxoByAddress: jest.fn(),
+  multiGetHistoryByAddress: jest.fn(),
+}));
+
+const coin = (txid: string, address: string): SilentPaymentUTXO => ({
+  txid,
+  vout: 0,
+  value: 1000,
+  height: 1,
+  address,
+  silentPaymentAddress: '',
+  pubKey: '',
+  tweak: new Uint8Array(32),
+  blockHash: '',
+  blockTime: 0,
+  isSpent: false,
+});
+
+describe('markSpentSilentPaymentUTXOs', () => {
+  it('marks only coins Electrum knows but no longer lists as unspent', async () => {
+    const wallet = new HDSilentPaymentsWallet();
+    // a: spent elsewhere · b: still unspent · c: Electrum hasn't seen its funding tx yet
+    (wallet as any)._utxo = [coin('aa', 'addr-a'), coin('bb', 'addr-b'), coin('cc', 'addr-c')];
+
+    (Electrum.multiGetUtxoByAddress as jest.Mock).mockResolvedValue({
+      'addr-a': [],
+      'addr-b': [{ txid: 'bb', vout: 0 }],
+      'addr-c': [],
+    });
+    (Electrum.multiGetHistoryByAddress as jest.Mock).mockResolvedValue({
+      'addr-a': [{ tx_hash: 'aa' }, { tx_hash: 'spender' }],
+      'addr-b': [{ tx_hash: 'bb' }],
+      'addr-c': [],
+    });
+
+    await (wallet as any).markSpentSilentPaymentUTXOs();
+
+    expect(wallet.getUTXOs().map(u => u.txid)).toEqual(['bb', 'cc']);
+  });
+
+  it('changes nothing when Electrum fails', async () => {
+    const wallet = new HDSilentPaymentsWallet();
+    (wallet as any)._utxo = [coin('aa', 'addr-a')];
+    (Electrum.multiGetUtxoByAddress as jest.Mock).mockRejectedValue(new Error('offline'));
+
+    await (wallet as any).markSpentSilentPaymentUTXOs();
+
+    expect(wallet.getUTXOs()).toHaveLength(1);
+  });
+});