Pass chain and client variables where needed

This commit does not change behavior. All it does is pass new function
parameters.

It is easiest to review this change with:

    git log -p -n1 -U0 --word-diff-regex=.

24 files changed, 138 insertions, 63 deletions

diff --git a/src/bench/coin_selection.cpp b/src/bench/coin_selection.cpp
index decdadfb26..8552ed34fd 100644
--- a/src/bench/coin_selection.cpp
+++ b/src/bench/coin_selection.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <bench/bench.h>
+#include <interfaces/chain.h>
 #include <wallet/wallet.h>
 #include <wallet/coinselection.h>
 
@@ -33,7 +34,8 @@ static void addCoin(const CAmount& nValue, const CWallet& wallet, std::vector<Ou
 // (https://github.com/bitcoin/bitcoin/issues/7883#issuecomment-224807484)
 static void CoinSelection(benchmark::State& state)
 {
-    const CWallet wallet(WalletLocation(), WalletDatabase::CreateDummy());
+    auto chain = interfaces::MakeChain();
+    const CWallet wallet(*chain, WalletLocation(), WalletDatabase::CreateDummy());
     LOCK(wallet.cs_wallet);
 
     // Add coins.
@@ -57,7 +59,8 @@ static void CoinSelection(benchmark::State& state)
 }
 
 typedef std::set<CInputCoin> CoinSet;
-static const CWallet testWallet(WalletLocation(), WalletDatabase::CreateDummy());
+static auto testChain = interfaces::MakeChain();
+static const CWallet testWallet(*testChain, WalletLocation(), WalletDatabase::CreateDummy());
 std::vector<std::unique_ptr<CWalletTx>> wtxn;
 
 // Copied from src/wallet/test/coinselector_tests.cpp
diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
index c6e2a7c20a..1306ba3821 100644
--- a/src/bitcoind.cpp
+++ b/src/bitcoind.cpp
@@ -11,6 +11,7 @@
 #include <clientversion.h>
 #include <compat.h>
 #include <fs.h>
+#include <interfaces/chain.h>
 #include <rpc/server.h>
 #include <init.h>
 #include <noui.h>
@@ -58,6 +59,9 @@ static void WaitForShutdown()
 //
 static bool AppInit(int argc, char* argv[])
 {
+    InitInterfaces interfaces;
+    interfaces.chain = interfaces::MakeChain();
+
     bool fRet = false;
 
     //
@@ -164,7 +168,7 @@ static bool AppInit(int argc, char* argv[])
             // If locking the data directory failed, exit immediately
             return false;
         }
-        fRet = AppInitMain();
+        fRet = AppInitMain(interfaces);
     }
     catch (const std::exception& e) {
         PrintExceptionContinue(&e, "AppInit()");
@@ -178,7 +182,7 @@ static bool AppInit(int argc, char* argv[])
     } else {
         WaitForShutdown();
     }
-    Shutdown();
+    Shutdown(interfaces);
 
     return fRet;
 }
diff --git a/src/dummywallet.cpp b/src/dummywallet.cpp
index 2a9b297029..fa232d2dd0 100644
--- a/src/dummywallet.cpp
+++ b/src/dummywallet.cpp
@@ -15,8 +15,8 @@ public:
     void AddWalletOptions() const override;
     bool ParameterInteraction() const override {return true;}
     void RegisterRPC(CRPCTable &) const override {}
-    bool Verify() const override {return true;}
-    bool Open() const override {LogPrintf("No wallet support compiled in!\n"); return true;}
+    bool Verify(interfaces::Chain& chain) const override {return true;}
+    bool Open(interfaces::Chain& chain) const override {LogPrintf("No wallet support compiled in!\n"); return true;}
     void Start(CScheduler& scheduler) const override {}
     void Flush() const override {}
     void Stop() const override {}
diff --git a/src/init.cpp b/src/init.cpp
index d54d4a8782..88d4d059f9 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -32,6 +32,7 @@
 #include <rpc/server.h>
 #include <rpc/register.h>
 #include <rpc/blockchain.h>
+#include <rpc/util.h>
 #include <script/standard.h>
 #include <script/sigcache.h>
 #include <scheduler.h>
@@ -157,7 +158,7 @@ void Interrupt()
     }
 }
 
-void Shutdown()
+void Shutdown(InitInterfaces& interfaces)
 {
     LogPrintf("%s: In progress...\n", __func__);
     static CCriticalSection cs_Shutdown;
@@ -1158,7 +1159,7 @@ bool AppInitLockDataDirectory()
     return true;
 }
 
-bool AppInitMain()
+bool AppInitMain(InitInterfaces& interfaces)
 {
     const CChainParams& chainparams = Params();
     // ********************************************************* Step 4a: application initialization
@@ -1226,6 +1227,7 @@ bool AppInitMain()
      */
     RegisterAllCoreRPCCommands(tableRPC);
     g_wallet_init_interface.RegisterRPC(tableRPC);
+    g_rpc_interfaces = &interfaces;
 #if ENABLE_ZMQ
     RegisterZMQRPCCommands(tableRPC);
 #endif
@@ -1243,7 +1245,7 @@ bool AppInitMain()
     }
 
     // ********************************************************* Step 5: verify wallet database integrity
-    if (!g_wallet_init_interface.Verify()) return false;
+    if (!g_wallet_init_interface.Verify(*interfaces.chain)) return false;
 
     // ********************************************************* Step 6: network initialization
     // Note that we absolutely cannot open any actual connections
@@ -1562,7 +1564,7 @@ bool AppInitMain()
     }
 
     // ********************************************************* Step 9: load wallet
-    if (!g_wallet_init_interface.Open()) return false;
+    if (!g_wallet_init_interface.Open(*interfaces.chain)) return false;
 
     // ********************************************************* Step 10: data directory maintenance
 
diff --git a/src/init.h b/src/init.h
index b106353d08..1c59ca069e 100644
--- a/src/init.h
+++ b/src/init.h
@@ -10,8 +10,17 @@
 #include <string>
 #include <util/system.h>
 
-class CScheduler;
-class CWallet;
+namespace interfaces {
+class Chain;
+class ChainClient;
+} // namespace interfaces
+
+//! Pointers to interfaces used during init and destroyed on shutdown.
+struct InitInterfaces
+{
+    std::unique_ptr<interfaces::Chain> chain;
+    std::vector<std::unique_ptr<interfaces::ChainClient>> chain_clients;
+};
 
 namespace boost
 {
@@ -20,7 +29,7 @@ class thread_group;
 
 /** Interrupt threads */
 void Interrupt();
-void Shutdown();
+void Shutdown(InitInterfaces& interfaces);
 //!Initialize the logging infrastructure
 void InitLogging();
 //!Parameter interaction: change current parameters depending on various rules
@@ -54,7 +63,7 @@ bool AppInitLockDataDirectory();
  * @note This should only be done after daemonization. Call Shutdown() if this function fails.
  * @pre Parameters should be parsed and config file should be read, AppInitLockDataDirectory should have been called.
  */
-bool AppInitMain();
+bool AppInitMain(InitInterfaces& interfaces);
 
 /**
  * Setup the arguments for gArgs
diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
index 490c456e6e..1919e16a66 100644
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -9,6 +9,7 @@
 #include <chain.h>
 #include <chainparams.h>
 #include <init.h>
+#include <interfaces/chain.h>
 #include <interfaces/handler.h>
 #include <interfaces/wallet.h>
 #include <net.h>
@@ -50,6 +51,8 @@ namespace {
 
 class NodeImpl : public Node
 {
+public:
+    NodeImpl() { m_interfaces.chain = MakeChain(); }
     bool parseParameters(int argc, const char* const argv[], std::string& error) override
     {
         return gArgs.ParseParameters(argc, argv, error);
@@ -68,11 +71,11 @@ class NodeImpl : public Node
         return AppInitBasicSetup() && AppInitParameterInteraction() && AppInitSanityChecks() &&
                AppInitLockDataDirectory();
     }
-    bool appInitMain() override { return AppInitMain(); }
+    bool appInitMain() override { return AppInitMain(m_interfaces); }
     void appShutdown() override
     {
         Interrupt();
-        Shutdown();
+        Shutdown(m_interfaces);
     }
     void startShutdown() override { StartShutdown(); }
     bool shutdownRequested() override { return ShutdownRequested(); }
@@ -291,6 +294,7 @@ class NodeImpl : public Node
                     GuessVerificationProgress(Params().TxData(), block));
             }));
     }
+    InitInterfaces m_interfaces;
 };
 
 } // namespace
diff --git a/src/qt/test/addressbooktests.cpp b/src/qt/test/addressbooktests.cpp
index 0cabb5f0be..3e414df1f0 100644
--- a/src/qt/test/addressbooktests.cpp
+++ b/src/qt/test/addressbooktests.cpp
@@ -2,6 +2,7 @@
 #include <qt/test/util.h>
 #include <test/test_bitcoin.h>
 
+#include <interfaces/chain.h>
 #include <interfaces/node.h>
 #include <qt/addressbookpage.h>
 #include <qt/addresstablemodel.h>
@@ -56,7 +57,8 @@ void EditAddressAndSubmit(
 void TestAddAddressesToSendBook()
 {
     TestChain100Setup test;
-    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateMock());
+    auto chain = interfaces::MakeChain();
+    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateMock());
     bool firstRun;
     wallet->LoadWallet(firstRun);
 
diff --git a/src/qt/test/wallettests.cpp b/src/qt/test/wallettests.cpp
index 12dbf922f1..57ae2150c8 100644
--- a/src/qt/test/wallettests.cpp
+++ b/src/qt/test/wallettests.cpp
@@ -1,6 +1,7 @@
 #include <qt/test/wallettests.h>
 #include <qt/test/util.h>
 
+#include <interfaces/chain.h>
 #include <interfaces/node.h>
 #include <base58.h>
 #include <qt/bitcoinamountfield.h>
@@ -132,7 +133,8 @@ void TestGUI()
     for (int i = 0; i < 5; ++i) {
         test.CreateAndProcessBlock({}, GetScriptForRawPubKey(test.coinbaseKey.GetPubKey()));
     }
-    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateMock());
+    auto chain = interfaces::MakeChain();
+    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateMock());
     bool firstRun;
     wallet->LoadWallet(firstRun);
     {
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 0f87646b08..fa886f6570 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -9,6 +9,7 @@
 #include <consensus/validation.h>
 #include <core_io.h>
 #include <index/txindex.h>
+#include <init.h>
 #include <keystore.h>
 #include <validation.h>
 #include <validationinterface.h>
@@ -20,6 +21,7 @@
 #include <primitives/transaction.h>
 #include <rpc/rawtransaction.h>
 #include <rpc/server.h>
+#include <rpc/util.h>
 #include <script/script.h>
 #include <script/script_error.h>
 #include <script/sign.h>
@@ -754,7 +756,7 @@ static UniValue combinerawtransaction(const JSONRPCRequest& request)
     return EncodeHexTx(mergedTx);
 }
 
-UniValue SignTransaction(CMutableTransaction& mtx, const UniValue& prevTxsUnival, CBasicKeyStore *keystore, bool is_temp_keystore, const UniValue& hashType)
+UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, const UniValue& prevTxsUnival, CBasicKeyStore *keystore, bool is_temp_keystore, const UniValue& hashType)
 {
     // Fetch previous transactions (inputs):
     CCoinsView viewDummy;
@@ -969,7 +971,7 @@ static UniValue signrawtransactionwithkey(const JSONRPCRequest& request)
         keystore.AddKey(key);
     }
 
-    return SignTransaction(mtx, request.params[2], &keystore, true, request.params[3]);
+    return SignTransaction(*g_rpc_interfaces->chain, mtx, request.params[2], &keystore, true, request.params[3]);
 }
 
 UniValue signrawtransaction(const JSONRPCRequest& request)
diff --git a/src/rpc/rawtransaction.h b/src/rpc/rawtransaction.h
index 924611ed5a..52d701d1c3 100644
--- a/src/rpc/rawtransaction.h
+++ b/src/rpc/rawtransaction.h
@@ -9,8 +9,12 @@ class CBasicKeyStore;
 struct CMutableTransaction;
 class UniValue;
 
+namespace interfaces {
+class Chain;
+} // namespace interfaces
+
 /** Sign a transaction with the given keystore and previous transactions */
-UniValue SignTransaction(CMutableTransaction& mtx, const UniValue& prevTxs, CBasicKeyStore *keystore, bool tempKeystore, const UniValue& hashType);
+UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, const UniValue& prevTxs, CBasicKeyStore *keystore, bool tempKeystore, const UniValue& hashType);
 
 /** Create a transaction from univalue parameters */
 CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf);
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index 8a66191a6a..ef2d14b90e 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -9,6 +9,8 @@
 #include <tinyformat.h>
 #include <util/strencodings.h>
 
+InitInterfaces* g_rpc_interfaces = nullptr;
+
 // Converts a hex string to a public key if possible
 CPubKey HexToPubKey(const std::string& hex_in)
 {
diff --git a/src/rpc/util.h b/src/rpc/util.h
index 0a3a156e45..e21b5ba22a 100644
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -17,6 +17,12 @@
 class CKeyStore;
 class CPubKey;
 class CScript;
+struct InitInterfaces;
+
+//! Pointers to interfaces that need to be accessible from RPC methods. Due to
+//! limitations of the RPC framework, there's currently no direct way to pass in
+//! state to RPC method implementations.
+extern InitInterfaces* g_rpc_interfaces;
 
 CPubKey HexToPubKey(const std::string& hex_in);
 CPubKey AddrToPubKey(CKeyStore* const keystore, const std::string& addr_in);
diff --git a/src/test/rpc_tests.cpp b/src/test/rpc_tests.cpp
index a49796d6f4..121b72a5f7 100644
--- a/src/test/rpc_tests.cpp
+++ b/src/test/rpc_tests.cpp
@@ -4,8 +4,11 @@
 
 #include <rpc/server.h>
 #include <rpc/client.h>
+#include <rpc/util.h>
 
 #include <core_io.h>
+#include <init.h>
+#include <interfaces/chain.h>
 #include <key_io.h>
 #include <netbase.h>
 
@@ -112,10 +115,14 @@ BOOST_AUTO_TEST_CASE(rpc_rawsign)
     std::string notsigned = r.get_str();
     std::string privkey1 = "\"KzsXybp9jX64P5ekX1KUxRQ79Jht9uzW7LorgwE65i5rWACL6LQe\"";
     std::string privkey2 = "\"Kyhdf5LuKTRx4ge69ybABsiUAWjVRK4XGxAKk2FQLp2HjGMy87Z4\"";
+    InitInterfaces interfaces;
+    interfaces.chain = interfaces::MakeChain();
+    g_rpc_interfaces = &interfaces;
     r = CallRPC(std::string("signrawtransactionwithkey ")+notsigned+" [] "+prevout);
     BOOST_CHECK(find_value(r.get_obj(), "complete").get_bool() == false);
     r = CallRPC(std::string("signrawtransactionwithkey ")+notsigned+" ["+privkey1+","+privkey2+"] "+prevout);
     BOOST_CHECK(find_value(r.get_obj(), "complete").get_bool() == true);
+    g_rpc_interfaces = nullptr;
 }
 
 BOOST_AUTO_TEST_CASE(rpc_createraw_op_return)
diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 456422d004..5ae9304904 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -34,10 +34,10 @@ public:
     //! Responsible for reading and validating the -wallet arguments and verifying the wallet database.
     //  This function will perform salvage on the wallet if requested, as long as only one wallet is
     //  being loaded (WalletParameterInteraction forbids -salvagewallet, -zapwallettxes or -upgradewallet with multiwallet).
-    bool Verify() const override;
+    bool Verify(interfaces::Chain& chain) const override;
 
     //! Load wallet databases.
-    bool Open() const override;
+    bool Open(interfaces::Chain& chain) const override;
 
     //! Complete startup of wallets.
     void Start(CScheduler& scheduler) const override;
@@ -174,7 +174,7 @@ void WalletInit::RegisterRPC(CRPCTable &t) const
     RegisterWalletRPCCommands(t);
 }
 
-bool WalletInit::Verify() const
+bool WalletInit::Verify(interfaces::Chain& chain) const
 {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         return true;
@@ -219,7 +219,7 @@ bool WalletInit::Verify() const
 
         std::string error_string;
         std::string warning_string;
-        bool verify_success = CWallet::Verify(location, salvage_wallet, error_string, warning_string);
+        bool verify_success = CWallet::Verify(chain, location, salvage_wallet, error_string, warning_string);
         if (!error_string.empty()) InitError(error_string);
         if (!warning_string.empty()) InitWarning(warning_string);
         if (!verify_success) return false;
@@ -228,7 +228,7 @@ bool WalletInit::Verify() const
     return true;
 }
 
-bool WalletInit::Open() const
+bool WalletInit::Open(interfaces::Chain& chain) const
 {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         LogPrintf("Wallet disabled!\n");
@@ -236,7 +236,7 @@ bool WalletInit::Open() const
     }
 
     for (const std::string& walletFile : gArgs.GetArgs("-wallet")) {
-        std::shared_ptr<CWallet> pwallet = CWallet::CreateWalletFromFile(WalletLocation(walletFile));
+        std::shared_ptr<CWallet> pwallet = CWallet::CreateWalletFromFile(chain, WalletLocation(walletFile));
         if (!pwallet) {
             return false;
         }
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 45d4b5bceb..b8e874fec6 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -8,6 +8,7 @@
 #include <consensus/validation.h>
 #include <core_io.h>
 #include <httpserver.h>
+#include <init.h>
 #include <validation.h>
 #include <key_io.h>
 #include <net.h>
@@ -89,7 +90,7 @@ void EnsureWalletIsUnlocked(CWallet * const pwallet)
     }
 }
 
-static void WalletTxToJSON(const CWalletTx& wtx, UniValue& entry) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+static void WalletTxToJSON(interfaces::Chain& chain, const CWalletTx& wtx, UniValue& entry) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     int confirms = wtx.GetDepthInMainChain();
     entry.pushKV("confirmations", confirms);
@@ -1279,7 +1280,7 @@ static void ListTransactions(CWallet* const pwallet, const CWalletTx& wtx, int n
             entry.pushKV("vout", s.vout);
             entry.pushKV("fee", ValueFromAmount(-nFee));
             if (fLong)
-                WalletTxToJSON(wtx, entry);
+                WalletTxToJSON(pwallet->chain(), wtx, entry);
             entry.pushKV("abandoned", wtx.isAbandoned());
             ret.push_back(entry);
         }
@@ -1318,7 +1319,7 @@ static void ListTransactions(CWallet* const pwallet, const CWalletTx& wtx, int n
             }
             entry.pushKV("vout", r.vout);
             if (fLong)
-                WalletTxToJSON(wtx, entry);
+                WalletTxToJSON(pwallet->chain(), wtx, entry);
             ret.push_back(entry);
         }
     }
@@ -1665,7 +1666,7 @@ static UniValue gettransaction(const JSONRPCRequest& request)
     if (wtx.IsFromMe(filter))
         entry.pushKV("fee", ValueFromAmount(nFee));
 
-    WalletTxToJSON(wtx, entry);
+    WalletTxToJSON(pwallet->chain(), wtx, entry);
 
     UniValue details(UniValue::VARR);
     ListTransactions(pwallet, wtx, 0, false, details, filter);
@@ -2420,11 +2421,11 @@ static UniValue loadwallet(const JSONRPCRequest& request)
     }
 
     std::string warning;
-    if (!CWallet::Verify(location, false, error, warning)) {
+    if (!CWallet::Verify(*g_rpc_interfaces->chain, location, false, error, warning)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet file verification failed: " + error);
     }
 
-    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(location);
+    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(*g_rpc_interfaces->chain, location);
     if (!wallet) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet loading failed.");
     }
@@ -2472,11 +2473,11 @@ static UniValue createwallet(const JSONRPCRequest& request)
     }
 
     // Wallet::Verify will check if we're trying to create a wallet with a duplication name.
-    if (!CWallet::Verify(location, false, error, warning)) {
+    if (!CWallet::Verify(*g_rpc_interfaces->chain, location, false, error, warning)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet file verification failed: " + error);
     }
 
-    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(location, (disable_privatekeys ? (uint64_t)WALLET_FLAG_DISABLE_PRIVATE_KEYS : 0));
+    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(*g_rpc_interfaces->chain, location, (disable_privatekeys ? (uint64_t)WALLET_FLAG_DISABLE_PRIVATE_KEYS : 0));
     if (!wallet) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed.");
     }
@@ -3021,7 +3022,7 @@ UniValue signrawtransactionwithwallet(const JSONRPCRequest& request)
     LOCK2(cs_main, pwallet->cs_wallet);
     EnsureWalletIsUnlocked(pwallet);
 
-    return SignTransaction(mtx, request.params[1], pwallet, false, request.params[2]);
+    return SignTransaction(pwallet->chain(), mtx, request.params[1], pwallet, false, request.params[2]);
 }
 
 static UniValue bumpfee(const JSONRPCRequest& request)
diff --git a/src/wallet/test/coinselector_tests.cpp b/src/wallet/test/coinselector_tests.cpp
index a9464870ea..5c65acf601 100644
--- a/src/wallet/test/coinselector_tests.cpp
+++ b/src/wallet/test/coinselector_tests.cpp
@@ -28,7 +28,8 @@ std::vector<std::unique_ptr<CWalletTx>> wtxn;
 typedef std::set<CInputCoin> CoinSet;
 
 static std::vector<COutput> vCoins;
-static CWallet testWallet(WalletLocation(), WalletDatabase::CreateDummy());
+static auto testChain = interfaces::MakeChain();
+static CWallet testWallet(*testChain, WalletLocation(), WalletDatabase::CreateDummy());
 static CAmount balance = 0;
 
 CoinEligibilityFilter filter_standard(1, 6, 0);
diff --git a/src/wallet/test/init_test_fixture.h b/src/wallet/test/init_test_fixture.h
index 5684adbece..97f4b0926f 100644
--- a/src/wallet/test/init_test_fixture.h
+++ b/src/wallet/test/init_test_fixture.h
@@ -5,6 +5,7 @@
 #ifndef BITCOIN_WALLET_TEST_INIT_TEST_FIXTURE_H
 #define BITCOIN_WALLET_TEST_INIT_TEST_FIXTURE_H
 
+#include <interfaces/chain.h>
 #include <test/test_bitcoin.h>
 
 
@@ -16,6 +17,7 @@ struct InitWalletDirTestingSetup: public BasicTestingSetup {
     fs::path m_datadir;
     fs::path m_cwd;
     std::map<std::string, fs::path> m_walletdir_path_cases;
+    std::unique_ptr<interfaces::Chain> m_chain = interfaces::MakeChain();
 };
 
 #endif // BITCOIN_WALLET_TEST_INIT_TEST_FIXTURE_H
diff --git a/src/wallet/test/init_tests.cpp b/src/wallet/test/init_tests.cpp
index 7048547b2b..b28f22f1b8 100644
--- a/src/wallet/test/init_tests.cpp
+++ b/src/wallet/test/init_tests.cpp
@@ -17,7 +17,7 @@ BOOST_FIXTURE_TEST_SUITE(init_tests, InitWalletDirTestingSetup)
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_default)
 {
     SetWalletDir(m_walletdir_path_cases["default"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == true);
     fs::path walletdir = gArgs.GetArg("-walletdir", "");
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
@@ -27,7 +27,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_default)
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_custom)
 {
     SetWalletDir(m_walletdir_path_cases["custom"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == true);
     fs::path walletdir = gArgs.GetArg("-walletdir", "");
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["custom"]);
@@ -37,28 +37,28 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_custom)
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_does_not_exist)
 {
     SetWalletDir(m_walletdir_path_cases["nonexistent"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == false);
 }
 
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_is_not_directory)
 {
     SetWalletDir(m_walletdir_path_cases["file"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == false);
 }
 
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_is_not_relative)
 {
     SetWalletDir(m_walletdir_path_cases["relative"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == false);
 }
 
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_no_trailing)
 {
     SetWalletDir(m_walletdir_path_cases["trailing"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == true);
     fs::path walletdir = gArgs.GetArg("-walletdir", "");
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
@@ -68,7 +68,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_no_trailing)
 BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_no_trailing2)
 {
     SetWalletDir(m_walletdir_path_cases["trailing2"]);
-    bool result = g_wallet_init_interface.Verify();
+    bool result = g_wallet_init_interface.Verify(*m_chain);
     BOOST_CHECK(result == true);
     fs::path walletdir = gArgs.GetArg("-walletdir", "");
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
diff --git a/src/wallet/test/wallet_test_fixture.cpp b/src/wallet/test/wallet_test_fixture.cpp
index d42209ab15..a5fb1db86c 100644
--- a/src/wallet/test/wallet_test_fixture.cpp
+++ b/src/wallet/test/wallet_test_fixture.cpp
@@ -9,7 +9,7 @@
 #include <wallet/rpcwallet.h>
 
 WalletTestingSetup::WalletTestingSetup(const std::string& chainName):
-    TestingSetup(chainName), m_wallet(WalletLocation(), WalletDatabase::CreateMock())
+    TestingSetup(chainName), m_wallet(*m_chain, WalletLocation(), WalletDatabase::CreateMock())
 {
     bool fFirstRun;
     m_wallet.LoadWallet(fFirstRun);
diff --git a/src/wallet/test/wallet_test_fixture.h b/src/wallet/test/wallet_test_fixture.h
index ff8ec32b03..e6fe8c9473 100644
--- a/src/wallet/test/wallet_test_fixture.h
+++ b/src/wallet/test/wallet_test_fixture.h
@@ -7,6 +7,8 @@
 
 #include <test/test_bitcoin.h>
 
+#include <interfaces/chain.h>
+#include <interfaces/wallet.h>
 #include <wallet/wallet.h>
 
 #include <memory>
@@ -17,6 +19,7 @@ struct WalletTestingSetup: public TestingSetup {
     explicit WalletTestingSetup(const std::string& chainName = CBaseChainParams::MAIN);
     ~WalletTestingSetup();
 
+    std::unique_ptr<interfaces::Chain> m_chain = interfaces::MakeChain();
     CWallet m_wallet;
 };
 
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index 269a916829..6d943d63a4 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -34,6 +34,8 @@ static void AddKey(CWallet& wallet, const CKey& key)
 
 BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
 {
+    auto chain = interfaces::MakeChain();
+
     // Cap last block file size, and mine new block in a new block file.
     CBlockIndex* const nullBlock = nullptr;
     CBlockIndex* oldTip = chainActive.Tip();
@@ -46,7 +48,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // Verify ScanForWalletTransactions picks up transactions in both the old
     // and new block files.
     {
-        CWallet wallet(WalletLocation(), WalletDatabase::CreateDummy());
+        CWallet wallet(*chain, WalletLocation(), WalletDatabase::CreateDummy());
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
@@ -61,7 +63,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // Verify ScanForWalletTransactions only picks transactions in the new block
     // file.
     {
-        CWallet wallet(WalletLocation(), WalletDatabase::CreateDummy());
+        CWallet wallet(*chain, WalletLocation(), WalletDatabase::CreateDummy());
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
@@ -73,7 +75,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // before the missing block, and success for a key whose creation time is
     // after.
     {
-        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateDummy());
+        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateDummy());
         AddWallet(wallet);
         UniValue keys;
         keys.setArray();
@@ -115,6 +117,8 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
 // than or equal to key birthday.
 BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 {
+    auto chain = interfaces::MakeChain();
+
     // Create two blocks with same timestamp to verify that importwallet rescan
     // will pick up both blocks, not just the first.
     const int64_t BLOCK_TIME = chainActive.Tip()->GetBlockTimeMax() + 5;
@@ -134,7 +138,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 
     // Import key into wallet and call dumpwallet to create backup file.
     {
-        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateDummy());
+        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateDummy());
         LOCK(wallet->cs_wallet);
         wallet->mapKeyMetadata[coinbaseKey.GetPubKey().GetID()].nCreateTime = KEY_TIME;
         wallet->AddKeyPubKey(coinbaseKey, coinbaseKey.GetPubKey());
@@ -150,7 +154,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
     // Call importwallet RPC and verify all blocks with timestamps >= BLOCK_TIME
     // were scanned, and no prior blocks were scanned.
     {
-        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateDummy());
+        std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateDummy());
 
         JSONRPCRequest request;
         request.params.setArray();
@@ -180,7 +184,8 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 // debit functions.
 BOOST_FIXTURE_TEST_CASE(coin_mark_dirty_immature_credit, TestChain100Setup)
 {
-    CWallet wallet(WalletLocation(), WalletDatabase::CreateDummy());
+    auto chain = interfaces::MakeChain();
+    CWallet wallet(*chain, WalletLocation(), WalletDatabase::CreateDummy());
     CWalletTx wtx(&wallet, m_coinbase_txns.back());
     LOCK2(cs_main, wallet.cs_wallet);
     wtx.hashBlock = chainActive.Tip()->GetBlockHash();
@@ -273,7 +278,7 @@ public:
     ListCoinsTestingSetup()
     {
         CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
-        wallet = MakeUnique<CWallet>(WalletLocation(), WalletDatabase::CreateMock());
+        wallet = MakeUnique<CWallet>(*m_chain, WalletLocation(), WalletDatabase::CreateMock());
         bool firstRun;
         wallet->LoadWallet(firstRun);
         AddKey(*wallet, coinbaseKey);
@@ -311,6 +316,7 @@ public:
         return it->second;
     }
 
+    std::unique_ptr<interfaces::Chain> m_chain = interfaces::MakeChain();
     std::unique_ptr<CWallet> wallet;
 };
 
@@ -377,7 +383,8 @@ BOOST_FIXTURE_TEST_CASE(ListCoins, ListCoinsTestingSetup)
 
 BOOST_FIXTURE_TEST_CASE(wallet_disableprivkeys, TestChain100Setup)
 {
-    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(WalletLocation(), WalletDatabase::CreateDummy());
+    auto chain = interfaces::MakeChain();
+    std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(*chain, WalletLocation(), WalletDatabase::CreateDummy());
     wallet->SetWalletFlag(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
     BOOST_CHECK(!wallet->TopUpKeyPool(1000));
     CPubKey pubkey;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2ea9f45462..7c9708cf5e 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -3825,7 +3825,7 @@ void CWallet::MarkPreSplitKeys()
     }
 }
 
-bool CWallet::Verify(const WalletLocation& location, bool salvage_wallet, std::string& error_string, std::string& warning_string)
+bool CWallet::Verify(interfaces::Chain& chain, const WalletLocation& location, bool salvage_wallet, std::string& error_string, std::string& warning_string)
 {
     // Do some checking on wallet path. It should be either a:
     //
@@ -3866,7 +3866,7 @@ bool CWallet::Verify(const WalletLocation& location, bool salvage_wallet, std::s
 
     if (salvage_wallet) {
         // Recover readable keypairs:
-        CWallet dummyWallet(WalletLocation(), WalletDatabase::CreateDummy());
+        CWallet dummyWallet(chain, WalletLocation(), WalletDatabase::CreateDummy());
         std::string backup_filename;
         if (!WalletBatch::Recover(wallet_path, (void *)&dummyWallet, WalletBatch::RecoverKeysOnlyFilter, backup_filename)) {
             return false;
@@ -3876,7 +3876,7 @@ bool CWallet::Verify(const WalletLocation& location, bool salvage_wallet, std::s
     return WalletBatch::VerifyDatabaseFile(wallet_path, warning_string, error_string);
 }
 
-std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(const WalletLocation& location, uint64_t wallet_creation_flags)
+std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain, const WalletLocation& location, uint64_t wallet_creation_flags)
 {
     const std::string& walletFile = location.GetName();
 
@@ -3886,7 +3886,7 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(const WalletLocation& loc
     if (gArgs.GetBoolArg("-zapwallettxes", false)) {
         uiInterface.InitMessage(_("Zapping all transactions from wallet..."));
 
-        std::unique_ptr<CWallet> tempWallet = MakeUnique<CWallet>(location, WalletDatabase::Create(location.GetPath()));
+        std::unique_ptr<CWallet> tempWallet = MakeUnique<CWallet>(chain, location, WalletDatabase::Create(location.GetPath()));
         DBErrors nZapWalletRet = tempWallet->ZapWalletTx(vWtx);
         if (nZapWalletRet != DBErrors::LOAD_OK) {
             InitError(strprintf(_("Error loading %s: Wallet corrupted"), walletFile));
@@ -3900,7 +3900,7 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(const WalletLocation& loc
     bool fFirstRun = true;
     // TODO: Can't use std::make_shared because we need a custom deleter but
     // should be possible to use std::allocate_shared.
-    std::shared_ptr<CWallet> walletInstance(new CWallet(location, WalletDatabase::Create(location.GetPath())), ReleaseWallet);
+    std::shared_ptr<CWallet> walletInstance(new CWallet(chain, location, WalletDatabase::Create(location.GetPath())), ReleaseWallet);
     DBErrors nLoadWalletRet = walletInstance->LoadWallet(fFirstRun);
     if (nLoadWalletRet != DBErrors::LOAD_OK)
     {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 74eaa09506..32cd462c4c 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -33,6 +33,10 @@
 #include <utility>
 #include <vector>
 
+namespace interfaces {
+class Chain;
+} // namespace interfaces
+
 bool AddWallet(const std::shared_ptr<CWallet>& wallet);
 bool RemoveWallet(const std::shared_ptr<CWallet>& wallet);
 bool HasWallets();
@@ -676,6 +680,9 @@ private:
      */
     bool AddWatchOnly(const CScript& dest) override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
+    /** Interface for accessing chain state. */
+    interfaces::Chain& m_chain;
+
     /** Wallet location which includes wallet name (see WalletLocation). */
     WalletLocation m_location;
 
@@ -737,7 +744,7 @@ public:
     unsigned int nMasterKeyMaxID = 0;
 
     /** Construct wallet with specified name and database implementation. */
-    CWallet(const WalletLocation& location, std::unique_ptr<WalletDatabase> database) : m_location(location), database(std::move(database))
+    CWallet(interfaces::Chain& chain, const WalletLocation& location, std::unique_ptr<WalletDatabase> database) : m_chain(chain), m_location(location), database(std::move(database))
     {
     }
 
@@ -759,6 +766,9 @@ public:
 
     std::set<COutPoint> setLockedCoins GUARDED_BY(cs_wallet);
 
+    /** Interface for accessing chain state. */
+    interfaces::Chain& chain() const { return m_chain; }
+
     const CWalletTx* GetWalletTx(const uint256& hash) const;
 
     //! check whether we are allowed to upgrade (or already support) to the named feature
@@ -1057,10 +1067,10 @@ public:
     bool MarkReplaced(const uint256& originalHash, const uint256& newHash);
 
     //! Verify wallet naming and perform salvage on the wallet if required
-    static bool Verify(const WalletLocation& location, bool salvage_wallet, std::string& error_string, std::string& warning_string);
+    static bool Verify(interfaces::Chain& chain, const WalletLocation& location, bool salvage_wallet, std::string& error_string, std::string& warning_string);
 
     /* Initializes the wallet, returns a new CWallet instance or a null pointer in case of an error */
-    static std::shared_ptr<CWallet> CreateWalletFromFile(const WalletLocation& location, uint64_t wallet_creation_flags = 0);
+    static std::shared_ptr<CWallet> CreateWalletFromFile(interfaces::Chain& chain, const WalletLocation& location, uint64_t wallet_creation_flags = 0);
 
     /**
      * Wallet post-init setup
diff --git a/src/walletinitinterface.h b/src/walletinitinterface.h
index 6f12551273..fb6dcf60d0 100644
--- a/src/walletinitinterface.h
+++ b/src/walletinitinterface.h
@@ -10,6 +10,10 @@
 class CScheduler;
 class CRPCTable;
 
+namespace interfaces {
+class Chain;
+} // namespace interfaces
+
 class WalletInitInterface {
 public:
     /** Is the wallet component enabled */
@@ -21,9 +25,9 @@ public:
     /** Register wallet RPC*/
     virtual void RegisterRPC(CRPCTable &) const = 0;
     /** Verify wallets */
-    virtual bool Verify() const = 0;
+    virtual bool Verify(interfaces::Chain& chain) const = 0;
     /** Open wallets*/
-    virtual bool Open() const = 0;
+    virtual bool Open(interfaces::Chain& chain) const = 0;
     /** Start wallets*/
     virtual void Start(CScheduler& scheduler) const = 0;
     /** Flush Wallets*/