[wallet] Add change type to CCoinControl

src/wallet/coincontrol.h

@@ -16,7 +16,10 @@
 class CCoinControl
 {
 public:
+    //! Custom change destination, if not set an address is generated
     CTxDestination destChange;
+    //! Custom change type, ignored if destChange is set, defaults to g_change_type
+    OutputType change_type;
     //! If false, allows unselected inputs, but requires all selected inputs be used
     bool fAllowOtherInputs;
     //! Includes watch only addresses which match the ISMINE_WATCH_SOLVABLE criteria
@@ -40,6 +43,7 @@ public:
     void SetNull()
     {
         destChange = CNoDestination();
+        change_type = g_change_type;
         fAllowOtherInputs = false;
         fAllowWatchOnly = false;
         setSelected.clear();

src/wallet/wallet.cpp

@@ -2674,11 +2674,11 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nC
     return true;
 }
 
-OutputType CWallet::TransactionChangeType(const std::vector<CRecipient>& vecSend)
+OutputType CWallet::TransactionChangeType(OutputType change_type, const std::vector<CRecipient>& vecSend)
 {
     // If -changetype is specified, always use that change type.
-    if (g_change_type != OUTPUT_TYPE_NONE) {
-        return g_change_type;
+    if (change_type != OUTPUT_TYPE_NONE) {
+        return change_type;
     }
 
     // if g_address_type is legacy, use legacy address as change (even
@@ -2797,7 +2797,7 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
                     return false;
                 }
 
-                const OutputType change_type = TransactionChangeType(vecSend);
+                const OutputType change_type = TransactionChangeType(coin_control.change_type, vecSend);
 
                 LearnRelatedScripts(vchPubKey, change_type);
                 scriptChange = GetScriptForDestination(GetDestinationForKey(vchPubKey, change_type));

src/wallet/wallet.h

@@ -965,7 +965,7 @@ public:
     CAmount GetLegacyBalance(const isminefilter& filter, int minDepth, const std::string* account) const;
     CAmount GetAvailableBalance(const CCoinControl* coinControl = nullptr) const;
 
-    OutputType TransactionChangeType(const std::vector<CRecipient>& vecSend);
+    OutputType TransactionChangeType(OutputType change_type, const std::vector<CRecipient>& vecSend);
 
     /**
      * Insert additional inputs into the transaction by