Regression test for ResendWalletTransactions

Adds a regression test for the wallet's ResendWalletTransactions function, which uses a new, hidden RPC command "resendwallettransactions."

I refactored main's Broadcast signal so it is passed the best-block time, which let me remove a global variable shared between main.cpp and the wallet (nTimeBestReceived).

I also manually tested the "rebroadcast unconfirmed every half hour or so" functionality by:

1. Running bitcoind -connect=0.0.0.0:8333
2. Creating a couple of send-to-self transactions
3. Connect to a peer using -addnode
4. Waited a while, monitoring debug.log, until I see:
```2015-03-23 18:48:10 ResendWalletTransactions: rebroadcast 2 unconfirmed transactions```

One last change: don't bother putting ResendWalletTransactions messages in debug.log unless unconfirmed transactions were actually rebroadcast.

10 files changed, 88 insertions, 32 deletions

diff --git a/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index dc4e0f77bd..01e9fa57b2 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -16,6 +16,7 @@
 #   h) node0 should now have 2 unspent outputs;  send these to node2 via raw tx broadcast by node1
 #   i) have node1 mine a block
 #   j) check balances - node0 should have 0, node2 should have 100
+#   k) test ResendWalletTransactions - create transactions, startup fourth node, make sure it syncs
 #
 
 from test_framework import BitcoinTestFramework
@@ -26,7 +27,7 @@ class WalletTest (BitcoinTestFramework):
 
     def setup_chain(self):
         print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+        initialize_chain_clean(self.options.tmpdir, 4)
 
     def setup_network(self, split=False):
         self.nodes = start_nodes(3, self.options.tmpdir)
@@ -132,5 +133,23 @@ class WalletTest (BitcoinTestFramework):
         assert_equal(self.nodes[2].getbalance(), Decimal('59.99800000'))
         assert_equal(self.nodes[0].getbalance(), Decimal('39.99800000'))
 
+        # Test ResendWalletTransactions:
+        # Create a couple of transactions, then start up a fourth
+        # node (nodes[3]) and ask nodes[0] to rebroadcast.
+        # EXPECT: nodes[3] should have those transactions in its mempool.
+        txid1 = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 1)
+        txid2 = self.nodes[1].sendtoaddress(self.nodes[0].getnewaddress(), 1)
+        sync_mempools(self.nodes)
+
+        self.nodes.append(start_node(3, self.options.tmpdir))
+        connect_nodes_bi(self.nodes, 0, 3)
+        sync_blocks(self.nodes)
+
+        relayed = self.nodes[0].resendwallettransactions()
+        assert_equal(set(relayed), set([txid1, txid2]))
+        sync_mempools(self.nodes)
+
+        assert(txid1 in self.nodes[3].getrawmempool())
+
 if __name__ == '__main__':
     WalletTest ().main ()
diff --git a/src/main.cpp b/src/main.cpp
index 0ffacc338e..8f50e7fc16 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -4475,7 +4475,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
         // transactions become unconfirmed and spams other nodes.
         if (!fReindex && !fImporting && !IsInitialBlockDownload())
         {
-            GetMainSignals().Broadcast();
+            GetMainSignals().Broadcast(nTimeBestReceived);
         }
 
         //
diff --git a/src/main.h b/src/main.h
index b0bab6f7bf..31de3f6ac5 100644
--- a/src/main.h
+++ b/src/main.h
@@ -116,7 +116,6 @@ extern BlockMap mapBlockIndex;
 extern uint64_t nLastBlockTx;
 extern uint64_t nLastBlockSize;
 extern const std::string strMessageMagic;
-extern int64_t nTimeBestReceived;
 extern CWaitableCriticalSection csBestBlock;
 extern CConditionVariable cvBlockChange;
 extern bool fImporting;
diff --git a/src/rpcserver.cpp b/src/rpcserver.cpp
index ba71725222..d30fa32eb4 100644
--- a/src/rpcserver.cpp
+++ b/src/rpcserver.cpp
@@ -333,6 +333,9 @@ static const CRPCCommand vRPCCommands[] =
     { "hidden",             "invalidateblock",        &invalidateblock,        true,      false },
     { "hidden",             "reconsiderblock",        &reconsiderblock,        true,      false },
     { "hidden",             "setmocktime",            &setmocktime,            true,      false },
+#ifdef ENABLE_WALLET
+    { "hidden", "resendwallettransactions", &resendwallettransactions, true, true },
+#endif
 
 #ifdef ENABLE_WALLET
     /* Wallet */
diff --git a/src/rpcserver.h b/src/rpcserver.h
index f63438ecb8..7011d41fc1 100644
--- a/src/rpcserver.h
+++ b/src/rpcserver.h
@@ -207,6 +207,7 @@ extern json_spirit::Value getwalletinfo(const json_spirit::Array& params, bool f
 extern json_spirit::Value getblockchaininfo(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value getnetworkinfo(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value setmocktime(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value resendwallettransactions(const json_spirit::Array& params, bool fHelp);
 
 extern json_spirit::Value getrawtransaction(const json_spirit::Array& params, bool fHelp); // in rcprawtransaction.cpp
 extern json_spirit::Value listunspent(const json_spirit::Array& params, bool fHelp);
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index ae4cd3c592..aa9aefb0de 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -18,13 +18,13 @@ void RegisterValidationInterface(CValidationInterface* pwalletIn) {
     g_signals.UpdatedTransaction.connect(boost::bind(&CValidationInterface::UpdatedTransaction, pwalletIn, _1));
     g_signals.SetBestChain.connect(boost::bind(&CValidationInterface::SetBestChain, pwalletIn, _1));
     g_signals.Inventory.connect(boost::bind(&CValidationInterface::Inventory, pwalletIn, _1));
-    g_signals.Broadcast.connect(boost::bind(&CValidationInterface::ResendWalletTransactions, pwalletIn));
+    g_signals.Broadcast.connect(boost::bind(&CValidationInterface::ResendWalletTransactions, pwalletIn, _1));
     g_signals.BlockChecked.connect(boost::bind(&CValidationInterface::BlockChecked, pwalletIn, _1, _2));
 }
 
 void UnregisterValidationInterface(CValidationInterface* pwalletIn) {
     g_signals.BlockChecked.disconnect(boost::bind(&CValidationInterface::BlockChecked, pwalletIn, _1, _2));
-    g_signals.Broadcast.disconnect(boost::bind(&CValidationInterface::ResendWalletTransactions, pwalletIn));
+    g_signals.Broadcast.disconnect(boost::bind(&CValidationInterface::ResendWalletTransactions, pwalletIn, _1));
     g_signals.Inventory.disconnect(boost::bind(&CValidationInterface::Inventory, pwalletIn, _1));
     g_signals.SetBestChain.disconnect(boost::bind(&CValidationInterface::SetBestChain, pwalletIn, _1));
     g_signals.UpdatedTransaction.disconnect(boost::bind(&CValidationInterface::UpdatedTransaction, pwalletIn, _1));
diff --git a/src/validationinterface.h b/src/validationinterface.h
index b21b6e5782..cb261f6aa3 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -33,7 +33,7 @@ protected:
     virtual void SetBestChain(const CBlockLocator &locator) {};
     virtual void UpdatedTransaction(const uint256 &hash) {};
     virtual void Inventory(const uint256 &hash) {};
-    virtual void ResendWalletTransactions() {};
+    virtual void ResendWalletTransactions(int64_t nBestBlockTime) {};
     virtual void BlockChecked(const CBlock&, const CValidationState&) {};
     friend void ::RegisterValidationInterface(CValidationInterface*);
     friend void ::UnregisterValidationInterface(CValidationInterface*);
@@ -52,7 +52,7 @@ struct CMainSignals {
     /** Notifies listeners about an inventory item being seen on the network. */
     boost::signals2::signal<void (const uint256 &)> Inventory;
     /** Tells listeners to broadcast their data. */
-    boost::signals2::signal<void ()> Broadcast;
+    boost::signals2::signal<void (int64_t nBestBlockTime)> Broadcast;
     /** Notifies listeners of a block validation result */
     boost::signals2::signal<void (const CBlock&, const CValidationState&)> BlockChecked;
 };
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 9318c1b2b1..29f3eda15d 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -2096,3 +2096,25 @@ Value getwalletinfo(const Array& params, bool fHelp)
         obj.push_back(Pair("unlocked_until", nWalletUnlockTime));
     return obj;
 }
+
+Value resendwallettransactions(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 0)
+        throw runtime_error(
+            "resendwallettransactions\n"
+            "Immediately re-broadcast unconfirmed wallet transactions to all peers.\n"
+            "Intended only for testing; the wallet code periodically re-broadcasts\n"
+            "automatically.\n"
+            "Returns array of transaction ids that were re-broadcast.\n"
+            );
+
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
+    std::vector<uint256> txids = pwalletMain->ResendWalletTransactionsBefore(GetTime());
+    Array result;
+    BOOST_FOREACH(const uint256& txid, txids)
+    {
+        result.push_back(txid.ToString());
+    }
+    return result;
+}
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 09bcda577e..a10123002e 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1114,15 +1114,17 @@ void CWallet::ReacceptWalletTransactions()
     }
 }
 
-void CWalletTx::RelayWalletTransaction()
+bool CWalletTx::RelayWalletTransaction()
 {
     if (!IsCoinBase())
     {
         if (GetDepthInMainChain() == 0) {
             LogPrintf("Relaying wtx %s\n", GetHash().ToString());
             RelayTransaction((CTransaction)*this);
+            return true;
         }
     }
+    return false;
 }
 
 set<uint256> CWalletTx::GetConflicts() const
@@ -1324,7 +1326,31 @@ bool CWalletTx::IsTrusted() const
     return true;
 }
 
-void CWallet::ResendWalletTransactions()
+std::vector<uint256> CWallet::ResendWalletTransactionsBefore(int64_t nTime)
+{
+    std::vector<uint256> result;
+
+    LOCK(cs_wallet);
+    // Sort them in chronological order
+    multimap<unsigned int, CWalletTx*> mapSorted;
+    BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
+    {
+        CWalletTx& wtx = item.second;
+        // Don't rebroadcast if newer than nTime:
+        if (wtx.nTimeReceived > nTime)
+            continue;
+        mapSorted.insert(make_pair(wtx.nTimeReceived, &wtx));
+    }
+    BOOST_FOREACH(PAIRTYPE(const unsigned int, CWalletTx*)& item, mapSorted)
+    {
+        CWalletTx& wtx = *item.second;
+        if (wtx.RelayWalletTransaction())
+            result.push_back(wtx.GetHash());
+    }
+    return result;
+}
+
+void CWallet::ResendWalletTransactions(int64_t nBestBlockTime)
 {
     // Do this infrequently and randomly to avoid giving away
     // that these are our transactions.
@@ -1336,30 +1362,15 @@ void CWallet::ResendWalletTransactions()
         return;
 
     // Only do it if there's been a new block since last time
-    if (nTimeBestReceived < nLastResend)
+    if (nBestBlockTime < nLastResend)
         return;
     nLastResend = GetTime();
 
-    // Rebroadcast any of our txes that aren't in a block yet
-    LogPrintf("ResendWalletTransactions()\n");
-    {
-        LOCK(cs_wallet);
-        // Sort them in chronological order
-        multimap<unsigned int, CWalletTx*> mapSorted;
-        BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
-        {
-            CWalletTx& wtx = item.second;
-            // Don't rebroadcast until it's had plenty of time that
-            // it should have gotten in already by now.
-            if (nTimeBestReceived - (int64_t)wtx.nTimeReceived > 5 * 60)
-                mapSorted.insert(make_pair(wtx.nTimeReceived, &wtx));
-        }
-        BOOST_FOREACH(PAIRTYPE(const unsigned int, CWalletTx*)& item, mapSorted)
-        {
-            CWalletTx& wtx = *item.second;
-            wtx.RelayWalletTransaction();
-        }
-    }
+    // Rebroadcast unconfirmed txes older than 5 minutes before the last
+    // block was found:
+    std::vector<uint256> relayed = ResendWalletTransactionsBefore(nBestBlockTime-5*60);
+    if (!relayed.empty())
+        LogPrintf("%s: rebroadcast %u unconfirmed transactions\n", __func__, relayed.size());
 }
 
 /** @} */ // end of mapWallet
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 4a13f02195..6ae1c87b1d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -381,7 +381,7 @@ public:
     int64_t GetTxTime() const;
     int GetRequestCount() const;
 
-    void RelayWalletTransaction();
+    bool RelayWalletTransaction();
 
     std::set<uint256> GetConflicts() const;
 };
@@ -614,7 +614,8 @@ public:
     void EraseFromWallet(const uint256 &hash);
     int ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate = false);
     void ReacceptWalletTransactions();
-    void ResendWalletTransactions();
+    void ResendWalletTransactions(int64_t nBestBlockTime);
+    std::vector<uint256> ResendWalletTransactionsBefore(int64_t nTime);
     CAmount GetBalance() const;
     CAmount GetUnconfirmedBalance() const;
     CAmount GetImmatureBalance() const;