Allow the default key to be unavailable

This solves the issue where no default key can be added after -salvagewallet.

src/init.cpp

@@ -939,12 +939,12 @@ bool AppInit2(boost::thread_group& threadGroup)
         RandAddSeedPerfmon();
 
         CPubKey newDefaultKey;
-        if (!pwalletMain->GetKeyFromPool(newDefaultKey, false))
-            strErrors << _("Cannot initialize keypool") << "\n";
+        if (pwalletMain->GetKeyFromPool(newDefaultKey, false)) {
             pwalletMain->SetDefaultKey(newDefaultKey);
             if (!pwalletMain->SetAddressBookName(pwalletMain->vchDefaultKey.GetID(), ""))
                 strErrors << _("Cannot write default address") << "\n";
         }
+    }
 
     printf("%s", strErrors.str().c_str());
     printf(" wallet      %15"PRI64d"ms\n", GetTimeMillis() - nStart);

src/main.cpp

@@ -4158,7 +4158,10 @@ CBlockTemplate* CreateNewBlock(CReserveKey& reservekey)
     txNew.vin.resize(1);
     txNew.vin[0].prevout.SetNull();
     txNew.vout.resize(1);
-    txNew.vout[0].scriptPubKey << reservekey.GetReservedKey() << OP_CHECKSIG;
+    CPubKey pubkey;
+    if (!reservekey.GetReservedKey(pubkey))
+        return NULL;
+    txNew.vout[0].scriptPubKey << pubkey << OP_CHECKSIG;
 
     // Add our coinbase tx as first transaction
     pblock->vtx.push_back(txNew);

src/wallet.cpp

@@ -457,6 +457,7 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn)
                 return false;
 #ifndef QT_GUI
         // If default receiving address gets used, replace it with a new one
+        if (vchDefaultKey.IsValid()) {
             CScript scriptDefaultKey;
             scriptDefaultKey.SetDestination(vchDefaultKey.GetID());
             BOOST_FOREACH(const CTxOut& txout, wtx.vout)
@@ -471,6 +472,7 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn)
                     }
                 }
             }
+        }
 #endif
         // since AddToWallet is called directly for self-originating transactions, check for consumption of own coins
         WalletUpdateSpent(wtx);
@@ -1199,8 +1201,8 @@ bool CWallet::CreateTransaction(const vector<pair<CScript, int64> >& vecSend, CW
                     //  post-backup change.
 
                     // Reserve a new key pair from key pool
-                    CPubKey vchPubKey = reservekey.GetReservedKey();
-                    // assert(mapKeys.count(vchPubKey));
+                    CPubKey vchPubKey;
+                    assert(reservekey.GetReservedKey(vchPubKey)); // should never fail, as we just unlocked
 
                     // Fill a vout to ourself
                     // TODO: pass in scriptChange instead of reservekey so
@@ -1737,7 +1739,7 @@ set< set<CTxDestination> > CWallet::GetAddressGroupings()
     return ret;
 }
 
-CPubKey CReserveKey::GetReservedKey()
+bool CReserveKey::GetReservedKey(CPubKey& pubkey)
 {
     if (nIndex == -1)
     {
@@ -1745,14 +1747,17 @@ CPubKey CReserveKey::GetReservedKey()
         pwallet->ReserveKeyFromKeyPool(nIndex, keypool);
         if (nIndex != -1)
             vchPubKey = keypool.vchPubKey;
-        else
-        {
+        else {
+            if (pwallet->vchDefaultKey.IsValid()) {
                 printf("CReserveKey::GetReservedKey(): Warning: Using default key instead of a new key, top up your keypool!");
                 vchPubKey = pwallet->vchDefaultKey;
+            } else
+                return false;
         }
     }
     assert(vchPubKey.IsValid());
-    return vchPubKey;
+    pubkey = vchPubKey;
+    return true;
 }
 
 void CReserveKey::KeepKey()

src/wallet.h

@@ -331,7 +331,7 @@ public:
     }
 
     void ReturnKey();
-    CPubKey GetReservedKey();
+    bool GetReservedKey(CPubKey &pubkey);
     void KeepKey();
 };