Merge bitcoin/bitcoin#23106: Ensure wallet is unlocked before signing PSBT with walletprocesspsbt and GUI

7e3ee4cdd0 GUI: Ask user to unlock wallet before signing psbt (Samuel Dobson)
0f3acecf33 Add test that walletprocesspsbt requires unlocked wallet when signing (Samuel Dobson)
0e895212bb Ensure wallet is unlocked before signing in walletprocesspsbt (Samuel Dobson)

Pull request description:

  If signing a PSBT, we need to ensure the wallet is unlocked.

  Fixes #22874, fixes bitcoin-core/gui#312

ACKs for top commit:
  achow101:
    ACK 7e3ee4cdd0
  lsilva01:
    Code Review ACK https://github.com/bitcoin/bitcoin/pull/23106/commits/7e3ee4cdd0f60a2f549ba030fe96b90d61c036c5
  benthecarman:
    ACK 7e3ee4cdd0

Tree-SHA512: 6726a873582747900ab454ea21153a92be86808a4c1517dc2856b389876a2da9e8df1ffa9b567b6bd017038342c3544ecf5ca3c97744e7debe0a5ee65563687d

src/qt/psbtoperationsdialog.cpp

@@ -71,6 +71,9 @@ void PSBTOperationsDialog::signTransaction()
 {
     bool complete;
     size_t n_signed;
+
+    WalletModel::UnlockContext ctx(m_wallet_model->requestUnlock());
+
     TransactionError err = m_wallet_model->wallet().fillPSBT(SIGHASH_ALL, true /* sign */, true /* bip32derivs */, &n_signed, m_transaction_data, complete);
 
     if (err != TransactionError::OK) {
@@ -81,7 +84,9 @@ void PSBTOperationsDialog::signTransaction()
 
     updateTransactionDisplay();
 
-    if (!complete && n_signed < 1) {
+    if (!complete && !ctx.isValid()) {
+        showStatus(tr("Cannot sign inputs while wallet is locked."), StatusLevel::WARN);
+    } else if (!complete && n_signed < 1) {
         showStatus(tr("Could not sign any more inputs."), StatusLevel::WARN);
     } else if (!complete) {
         showStatus(tr("Signed %1 inputs, but more signatures are still required.").arg(n_signed),