Merge bitcoin/bitcoin#22220: util: make ParseMoney return a std::optional<CAmount>

f7752adba5dd35fccd3f2144cfcf03538ebf275b util: check MoneyRange() inside ParseMoney() (fanquake)
5ef2738089efd396186775ad23aaec71ea44ebb1 util: make ParseMoney return a std::optional<CAmount> (fanquake)

Pull request description:

  Related discussion in #22193.

ACKs for top commit:
  MarcoFalke:
    review ACK f7752adba5dd35fccd3f2144cfcf03538ebf275b 📄

Tree-SHA512: 88453f9e28f668deff4290d4bc0b2468cbd54699a3be1bfeac63a512276d309354672e7ea7deefa01466c3d9d826e837cc1ea244d4d74b4fa9c11c56f074e098

1 files changed, 36 insertions, 34 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index cf869fac0c..dbcfc4dac3 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2609,72 +2609,73 @@ std::shared_ptr<CWallet> CWallet::Create(WalletContext& context, const std::stri
     }
 
     if (gArgs.IsArgSet("-mintxfee")) {
-        CAmount n = 0;
-        if (!ParseMoney(gArgs.GetArg("-mintxfee", ""), n) || 0 == n) {
+        std::optional<CAmount> min_tx_fee = ParseMoney(gArgs.GetArg("-mintxfee", ""));
+        if (!min_tx_fee || min_tx_fee.value() == 0) {
             error = AmountErrMsg("mintxfee", gArgs.GetArg("-mintxfee", ""));
             return nullptr;
-        }
-        if (n > HIGH_TX_FEE_PER_KB) {
+        } else if (min_tx_fee.value() > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-mintxfee") + Untranslated(" ") +
                                _("This is the minimum transaction fee you pay on every transaction."));
         }
-        walletInstance->m_min_fee = CFeeRate(n);
+
+        walletInstance->m_min_fee = CFeeRate{min_tx_fee.value()};
     }
 
     if (gArgs.IsArgSet("-maxapsfee")) {
         const std::string max_aps_fee{gArgs.GetArg("-maxapsfee", "")};
-        CAmount n = 0;
         if (max_aps_fee == "-1") {
-            n = -1;
-        } else if (!ParseMoney(max_aps_fee, n)) {
+            walletInstance->m_max_aps_fee = -1;
+        } else if (std::optional<CAmount> max_fee = ParseMoney(max_aps_fee)) {
+            if (max_fee.value() > HIGH_APS_FEE) {
+                warnings.push_back(AmountHighWarn("-maxapsfee") + Untranslated(" ") +
+                                  _("This is the maximum transaction fee you pay (in addition to the normal fee) to prioritize partial spend avoidance over regular coin selection."));
+            }
+            walletInstance->m_max_aps_fee = max_fee.value();
+        } else {
             error = AmountErrMsg("maxapsfee", max_aps_fee);
             return nullptr;
         }
-        if (n > HIGH_APS_FEE) {
-            warnings.push_back(AmountHighWarn("-maxapsfee") + Untranslated(" ") +
-                              _("This is the maximum transaction fee you pay (in addition to the normal fee) to prioritize partial spend avoidance over regular coin selection."));
-        }
-        walletInstance->m_max_aps_fee = n;
     }
 
     if (gArgs.IsArgSet("-fallbackfee")) {
-        CAmount nFeePerK = 0;
-        if (!ParseMoney(gArgs.GetArg("-fallbackfee", ""), nFeePerK)) {
+        std::optional<CAmount> fallback_fee = ParseMoney(gArgs.GetArg("-fallbackfee", ""));
+        if (!fallback_fee) {
             error = strprintf(_("Invalid amount for -fallbackfee=<amount>: '%s'"), gArgs.GetArg("-fallbackfee", ""));
             return nullptr;
-        }
-        if (nFeePerK > HIGH_TX_FEE_PER_KB) {
+        } else if (fallback_fee.value() > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-fallbackfee") + Untranslated(" ") +
                                _("This is the transaction fee you may pay when fee estimates are not available."));
         }
-        walletInstance->m_fallback_fee = CFeeRate(nFeePerK);
+        walletInstance->m_fallback_fee = CFeeRate{fallback_fee.value()};
     }
+
     // Disable fallback fee in case value was set to 0, enable if non-null value
     walletInstance->m_allow_fallback_fee = walletInstance->m_fallback_fee.GetFeePerK() != 0;
 
     if (gArgs.IsArgSet("-discardfee")) {
-        CAmount nFeePerK = 0;
-        if (!ParseMoney(gArgs.GetArg("-discardfee", ""), nFeePerK)) {
+        std::optional<CAmount> discard_fee = ParseMoney(gArgs.GetArg("-discardfee", ""));
+        if (!discard_fee) {
             error = strprintf(_("Invalid amount for -discardfee=<amount>: '%s'"), gArgs.GetArg("-discardfee", ""));
             return nullptr;
-        }
-        if (nFeePerK > HIGH_TX_FEE_PER_KB) {
+        } else if (discard_fee.value() > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-discardfee") + Untranslated(" ") +
                                _("This is the transaction fee you may discard if change is smaller than dust at this level"));
         }
-        walletInstance->m_discard_rate = CFeeRate(nFeePerK);
+        walletInstance->m_discard_rate = CFeeRate{discard_fee.value()};
     }
+
     if (gArgs.IsArgSet("-paytxfee")) {
-        CAmount nFeePerK = 0;
-        if (!ParseMoney(gArgs.GetArg("-paytxfee", ""), nFeePerK)) {
+        std::optional<CAmount> pay_tx_fee = ParseMoney(gArgs.GetArg("-paytxfee", ""));
+        if (!pay_tx_fee) {
             error = AmountErrMsg("paytxfee", gArgs.GetArg("-paytxfee", ""));
             return nullptr;
-        }
-        if (nFeePerK > HIGH_TX_FEE_PER_KB) {
+        } else if (pay_tx_fee.value() > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-paytxfee") + Untranslated(" ") +
                                _("This is the transaction fee you will pay if you send a transaction."));
         }
-        walletInstance->m_pay_tx_fee = CFeeRate(nFeePerK, 1000);
+
+        walletInstance->m_pay_tx_fee = CFeeRate{pay_tx_fee.value(), 1000};
+
         if (chain && walletInstance->m_pay_tx_fee < chain->relayMinFee()) {
             error = strprintf(_("Invalid amount for -paytxfee=<amount>: '%s' (must be at least %s)"),
                 gArgs.GetArg("-paytxfee", ""), chain->relayMinFee().ToString());
@@ -2683,20 +2684,21 @@ std::shared_ptr<CWallet> CWallet::Create(WalletContext& context, const std::stri
     }
 
     if (gArgs.IsArgSet("-maxtxfee")) {
-        CAmount nMaxFee = 0;
-        if (!ParseMoney(gArgs.GetArg("-maxtxfee", ""), nMaxFee)) {
+        std::optional<CAmount> max_fee = ParseMoney(gArgs.GetArg("-maxtxfee", ""));
+        if (!max_fee) {
             error = AmountErrMsg("maxtxfee", gArgs.GetArg("-maxtxfee", ""));
             return nullptr;
-        }
-        if (nMaxFee > HIGH_MAX_TX_FEE) {
+        } else if (max_fee.value() > HIGH_MAX_TX_FEE) {
             warnings.push_back(_("-maxtxfee is set very high! Fees this large could be paid on a single transaction."));
         }
-        if (chain && CFeeRate(nMaxFee, 1000) < chain->relayMinFee()) {
+
+        if (chain && CFeeRate{max_fee.value(), 1000} < chain->relayMinFee()) {
             error = strprintf(_("Invalid amount for -maxtxfee=<amount>: '%s' (must be at least the minrelay fee of %s to prevent stuck transactions)"),
                 gArgs.GetArg("-maxtxfee", ""), chain->relayMinFee().ToString());
             return nullptr;
         }
-        walletInstance->m_default_max_tx_fee = nMaxFee;
+
+        walletInstance->m_default_max_tx_fee = max_fee.value();
     }
 
     if (chain && chain->relayMinFee().GetFeePerK() > HIGH_TX_FEE_PER_KB) {