wallet: Only fail rescan when blocks have actually been pruned

src/interfaces/chain.cpp

@@ -1,4 +1,4 @@
-// Copyright (c) 2018 The Bitcoin Core developers
+// Copyright (c) 2018-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -325,7 +325,11 @@ public:
     CFeeRate relayMinFee() override { return ::minRelayTxFee; }
     CFeeRate relayIncrementalFee() override { return ::incrementalRelayFee; }
     CFeeRate relayDustFee() override { return ::dustRelayFee; }
-    bool getPruneMode() override { return ::fPruneMode; }
+    bool havePruned() override
+    {
+        LOCK(cs_main);
+        return ::fHavePruned;
+    }
     bool p2pEnabled() override { return g_connman != nullptr; }
     bool isReadyToBroadcast() override { return !::fImporting && !::fReindex && !IsInitialBlockDownload(); }
     bool isInitialBlockDownload() override { return IsInitialBlockDownload(); }

src/interfaces/chain.h

@@ -1,4 +1,4 @@
-// Copyright (c) 2018 The Bitcoin Core developers
+// Copyright (c) 2018-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -207,8 +207,8 @@ public:
     //! Relay dust fee setting (-dustrelayfee), reflecting lowest rate it's economical to spend.
     virtual CFeeRate relayDustFee() = 0;
 
-    //! Check if pruning is enabled.
-    virtual bool getPruneMode() = 0;
+    //! Check if any block has been pruned.
+    virtual bool havePruned() = 0;
 
     //! Check if p2p enabled.
     virtual bool p2pEnabled() = 0;

src/wallet/rpcdump.cpp

@@ -157,8 +157,11 @@ UniValue importprivkey(const JSONRPCRequest& request)
         if (!request.params[2].isNull())
             fRescan = request.params[2].get_bool();
 
-        if (fRescan && pwallet->chain().getPruneMode()) {
-            throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled in pruned mode");
+        if (fRescan && pwallet->chain().havePruned()) {
+            // Exit early and print an error.
+            // If a block is pruned after this check, we will import the key(s),
+            // but fail the rescan with a generic error.
+            throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled when blocks are pruned");
         }
 
         if (fRescan && !reserver.reserve()) {
@@ -314,8 +317,11 @@ UniValue importaddress(const JSONRPCRequest& request)
     if (!request.params[2].isNull())
         fRescan = request.params[2].get_bool();
 
-    if (fRescan && pwallet->chain().getPruneMode()) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled in pruned mode");
+    if (fRescan && pwallet->chain().havePruned()) {
+        // Exit early and print an error.
+        // If a block is pruned after this check, we will import the key(s),
+        // but fail the rescan with a generic error.
+        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled when blocks are pruned");
     }
 
     WalletRescanReserver reserver(pwallet);
@@ -507,8 +513,11 @@ UniValue importpubkey(const JSONRPCRequest& request)
     if (!request.params[2].isNull())
         fRescan = request.params[2].get_bool();
 
-    if (fRescan && pwallet->chain().getPruneMode()) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled in pruned mode");
+    if (fRescan && pwallet->chain().havePruned()) {
+        // Exit early and print an error.
+        // If a block is pruned after this check, we will import the key(s),
+        // but fail the rescan with a generic error.
+        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled when blocks are pruned");
     }
 
     WalletRescanReserver reserver(pwallet);
@@ -573,7 +582,10 @@ UniValue importwallet(const JSONRPCRequest& request)
                 },
             }.ToString());
 
-    if (pwallet->chain().getPruneMode()) {
+    if (pwallet->chain().havePruned()) {
+        // Exit early and print an error.
+        // If a block is pruned after this check, we will import the key(s),
+        // but fail the rescan with a generic error.
         throw JSONRPCError(RPC_WALLET_ERROR, "Importing wallets is disabled in pruned mode");
     }
 

src/wallet/wallet.cpp

@@ -4219,10 +4219,13 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain,
 
     if (tip_height && *tip_height != rescan_height)
     {
-        //We can't rescan beyond non-pruned blocks, stop and throw an error
-        //this might happen if a user uses an old wallet within a pruned node
-        // or if he ran -disablewallet for a longer time, then decided to re-enable
-        if (chain.getPruneMode()) {
+        // We can't rescan beyond non-pruned blocks, stop and throw an error.
+        // This might happen if a user uses an old wallet within a pruned node
+        // or if they ran -disablewallet for a longer time, then decided to re-enable
+        if (chain.havePruned()) {
+            // Exit early and print an error.
+            // If a block is pruned after this check, we will load the wallet,
+            // but fail the rescan with a generic error.
             int block_height = *tip_height;
             while (block_height > 0 && locked_chain->haveBlockOnDisk(block_height - 1) && rescan_height != block_height) {
                 --block_height;

test/functional/wallet_import_rescan.py

@@ -21,7 +21,6 @@ happened previously.
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
-    assert_raises_rpc_error,
     connect_nodes,
     assert_equal,
     set_node_times,
@@ -39,23 +38,17 @@ Rescan = enum.Enum("Rescan", "no yes late_timestamp")
 class Variant(collections.namedtuple("Variant", "call data rescan prune")):
     """Helper for importing one key and verifying scanned transactions."""
 
-    def try_rpc(self, func, *args, **kwargs):
-        if self.expect_disabled:
-            assert_raises_rpc_error(-4, "Rescan is disabled in pruned mode", func, *args, **kwargs)
-        else:
-            return func(*args, **kwargs)
-
     def do_import(self, timestamp):
         """Call one key import RPC."""
         rescan = self.rescan == Rescan.yes
 
         if self.call == Call.single:
             if self.data == Data.address:
-                response = self.try_rpc(self.node.importaddress, address=self.address["address"], label=self.label, rescan=rescan)
+                response = self.node.importaddress(address=self.address["address"], label=self.label, rescan=rescan)
             elif self.data == Data.pub:
-                response = self.try_rpc(self.node.importpubkey, pubkey=self.address["pubkey"], label=self.label, rescan=rescan)
+                response = self.node.importpubkey(pubkey=self.address["pubkey"], label=self.label, rescan=rescan)
             elif self.data == Data.priv:
-                response = self.try_rpc(self.node.importprivkey, privkey=self.key, label=self.label, rescan=rescan)
+                response = self.node.importprivkey(privkey=self.key, label=self.label, rescan=rescan)
             assert_equal(response, None)
 
         elif self.call in (Call.multiaddress, Call.multiscript):
@@ -172,8 +165,7 @@ class ImportRescanTest(BitcoinTestFramework):
         # check the results from getbalance and listtransactions.
         for variant in IMPORT_VARIANTS:
             self.log.info('Run import for variant {}'.format(variant))
-            variant.expect_disabled = variant.rescan == Rescan.yes and variant.prune and variant.call == Call.single
-            expect_rescan = variant.rescan == Rescan.yes and not variant.expect_disabled
+            expect_rescan = variant.rescan == Rescan.yes
             variant.node = self.nodes[2 + IMPORT_NODES.index(ImportNode(variant.prune, expect_rescan))]
             variant.do_import(timestamp)
             if expect_rescan:
@@ -198,12 +190,9 @@ class ImportRescanTest(BitcoinTestFramework):
         # Check the latest results from getbalance and listtransactions.
         for variant in IMPORT_VARIANTS:
             self.log.info('Run check for variant {}'.format(variant))
-            if not variant.expect_disabled:
-                variant.expected_balance += variant.sent_amount
-                variant.expected_txs += 1
-                variant.check(variant.sent_txid, variant.sent_amount, 1)
-            else:
-                variant.check()
+            variant.expected_balance += variant.sent_amount
+            variant.expected_txs += 1
+            variant.check(variant.sent_txid, variant.sent_amount, 1)
 
 if __name__ == "__main__":
     ImportRescanTest().main()