Merge #18546: Bugfix: Wallet: Safely deal with change in the address book [part 2]

7a2ecf16df938dd95d3130a46082def7a02338eb Wallet: Change IsMine check in CWallet::DelAddressBook from assert to failure (Luke Dashjr)
2952c46b923042f2de801f319e03ed5c4c4eb735 Wallet: Replace CAddressBookData.name with GetLabel() method (Luke Dashjr)
d7092c392e10889cd7a080b3d22ed6446a59b87a QA: Test that change doesn't turn into non-change when spent in an avoid-reuse wallet (Luke Dashjr)

Pull request description:

  Follow-up to #18192, not strictly necessary for 0.20

ACKs for top commit:
  MarcoFalke:
    re-ACK 7a2ecf16df, only change is adding an assert_equal in the test 🔰
  jnewbery:
    utACK 7a2ecf16df938dd95d3130a46082def7a02338eb

Tree-SHA512: e0933ee40f705b751697dc27249e1868ed4874254b174ebdd0a7150125d8c818402e66df2371718c7eeb90e67ee2317215fb260aa9b9d7b9b45ee436de2988ff

6 files changed, 45 insertions, 17 deletions

diff --git a/src/interfaces/wallet.cpp b/src/interfaces/wallet.cpp
index d55b92a5ff..abce09ca4a 100644
--- a/src/interfaces/wallet.cpp
+++ b/src/interfaces/wallet.cpp
@@ -156,7 +156,7 @@ public:
             return false;
         }
         if (name) {
-            *name = it->second.name;
+            *name = it->second.GetLabel();
         }
         if (is_mine) {
             *is_mine = m_wallet->IsMine(dest);
@@ -172,7 +172,7 @@ public:
         std::vector<WalletAddress> result;
         for (const auto& item : m_wallet->m_address_book) {
             if (item.second.IsChange()) continue;
-            result.emplace_back(item.first, m_wallet->IsMine(item.first), item.second.name, item.second.purpose);
+            result.emplace_back(item.first, m_wallet->IsMine(item.first), item.second.GetLabel(), item.second.purpose);
         }
         return result;
     }
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index e1d8f51c4a..ea54027c48 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -66,7 +66,7 @@ static bool GetWalletAddressesForKey(LegacyScriptPubKeyMan* spk_man, const CWall
                 strAddr += ",";
             }
             strAddr += EncodeDestination(dest);
-            strLabel = EncodeDumpString(address_book_entry->name);
+            strLabel = EncodeDumpString(address_book_entry->GetLabel());
             fLabelFound = true;
         }
     }
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 336a6cff72..769a343365 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -501,7 +501,7 @@ static UniValue listaddressgroupings(const JSONRPCRequest& request)
             {
                 const auto* address_book_entry = pwallet->FindAddressBookEntry(address);
                 if (address_book_entry) {
-                    addressInfo.push_back(address_book_entry->name);
+                    addressInfo.push_back(address_book_entry->GetLabel());
                 }
             }
             jsonGrouping.push_back(addressInfo);
@@ -1109,7 +1109,7 @@ static UniValue ListReceived(interfaces::Chain::Lock& locked_chain, const CWalle
     {
         if (item_it->second.IsChange()) continue;
         const CTxDestination& address = item_it->first;
-        const std::string& label = item_it->second.name;
+        const std::string& label = item_it->second.GetLabel();
         auto it = mapTally.find(address);
         if (it == mapTally.end() && !fIncludeEmpty)
             continue;
@@ -1311,7 +1311,7 @@ static void ListTransactions(interfaces::Chain::Lock& locked_chain, const CWalle
             entry.pushKV("amount", ValueFromAmount(-s.amount));
             const auto* address_book_entry = pwallet->FindAddressBookEntry(s.destination);
             if (address_book_entry) {
-                entry.pushKV("label", address_book_entry->name);
+                entry.pushKV("label", address_book_entry->GetLabel());
             }
             entry.pushKV("vout", s.vout);
             entry.pushKV("fee", ValueFromAmount(-nFee));
@@ -1329,7 +1329,7 @@ static void ListTransactions(interfaces::Chain::Lock& locked_chain, const CWalle
             std::string label;
             const auto* address_book_entry = pwallet->FindAddressBookEntry(r.destination);
             if (address_book_entry) {
-                label = address_book_entry->name;
+                label = address_book_entry->GetLabel();
             }
             if (filter_label && label != *filter_label) {
                 continue;
@@ -2963,7 +2963,7 @@ static UniValue listunspent(const JSONRPCRequest& request)
 
             const auto* address_book_entry = pwallet->FindAddressBookEntry(address);
             if (address_book_entry) {
-                entry.pushKV("label", address_book_entry->name);
+                entry.pushKV("label", address_book_entry->GetLabel());
             }
 
             std::unique_ptr<SigningProvider> provider = pwallet->GetSolvingProvider(scriptPubKey);
@@ -3710,7 +3710,7 @@ static UniValue AddressBookDataToJSON(const CAddressBookData& data, const bool v
 {
     UniValue ret(UniValue::VOBJ);
     if (verbose) {
-        ret.pushKV("name", data.name);
+        ret.pushKV("name", data.GetLabel());
     }
     ret.pushKV("purpose", data.purpose);
     return ret;
@@ -3822,7 +3822,7 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
     // value of the name key/value pair in the labels array below.
     const auto* address_book_entry = pwallet->FindAddressBookEntry(dest);
     if (pwallet->chain().rpcEnableDeprecated("label") && address_book_entry) {
-        ret.pushKV("label", address_book_entry->name);
+        ret.pushKV("label", address_book_entry->GetLabel());
     }
 
     ret.pushKV("ischange", pwallet->IsChange(scriptPubKey));
@@ -3851,7 +3851,7 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
         if (pwallet->chain().rpcEnableDeprecated("labelspurpose")) {
             labels.push_back(AddressBookDataToJSON(*address_book_entry, true));
         } else {
-            labels.push_back(address_book_entry->name);
+            labels.push_back(address_book_entry->GetLabel());
         }
     }
     ret.pushKV("labels", std::move(labels));
@@ -3897,7 +3897,7 @@ static UniValue getaddressesbylabel(const JSONRPCRequest& request)
     std::set<std::string> addresses;
     for (const std::pair<const CTxDestination, CAddressBookData>& item : pwallet->m_address_book) {
         if (item.second.IsChange()) continue;
-        if (item.second.name == label) {
+        if (item.second.GetLabel() == label) {
             std::string address = EncodeDestination(item.first);
             // CWallet::m_address_book is not expected to contain duplicate
             // address strings, but build a separate set as a precaution just in
@@ -3963,7 +3963,7 @@ static UniValue listlabels(const JSONRPCRequest& request)
     for (const std::pair<const CTxDestination, CAddressBookData>& entry : pwallet->m_address_book) {
         if (entry.second.IsChange()) continue;
         if (purpose.empty() || entry.second.purpose == purpose) {
-            label_set.insert(entry.second.name);
+            label_set.insert(entry.second.GetLabel());
         }
     }
 
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 9ee3bbd038..45f5542cad 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -3221,7 +3221,10 @@ bool CWallet::DelAddressBook(const CTxDestination& address)
     // If we want to delete receiving addresses, we need to take care that DestData "used" (and possibly newer DestData) gets preserved (and the "deleted" address transformed into a change entry instead of actually being deleted)
     // NOTE: This isn't a problem for sending addresses because they never have any DestData yet!
     // When adding new DestData, it should be considered here whether to retain or delete it (or move it?).
-    assert(!IsMine(address));
+    if (IsMine(address)) {
+        WalletLogPrintf("%s called with IsMine address, NOT SUPPORTED. Please report this bug! %s\n", __func__, PACKAGE_BUGREPORT);
+        return false;
+    }
 
     {
         LOCK(cs_wallet);
@@ -3472,7 +3475,7 @@ std::set<CTxDestination> CWallet::GetLabelAddresses(const std::string& label) co
     {
         if (item.second.IsChange()) continue;
         const CTxDestination& address = item.first;
-        const std::string& strName = item.second.name;
+        const std::string& strName = item.second.GetLabel();
         if (strName == label)
             result.insert(address);
     }
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 7e770a40f2..6c54c72e76 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -185,15 +185,15 @@ private:
     bool m_change{true};
     std::string m_label;
 public:
-    const std::string& name;
     std::string purpose;
 
-    CAddressBookData() : name(m_label), purpose("unknown") {}
+    CAddressBookData() : purpose("unknown") {}
 
     typedef std::map<std::string, std::string> StringMap;
     StringMap destdata;
 
     bool IsChange() const { return m_change; }
+    const std::string& GetLabel() const { return m_label; }
     void SetLabel(const std::string& label) {
         m_change = false;
         m_label = label;
diff --git a/test/functional/wallet_avoidreuse.py b/test/functional/wallet_avoidreuse.py
index 8e2dc03ac2..2ce8d459c6 100755
--- a/test/functional/wallet_avoidreuse.py
+++ b/test/functional/wallet_avoidreuse.py
@@ -83,6 +83,7 @@ class AvoidReuseTest(BitcoinTestFramework):
 
         self.nodes[0].generate(110)
         self.sync_all()
+        self.test_change_remains_change(self.nodes[1])
         reset_balance(self.nodes[1], self.nodes[0].getnewaddress())
         self.test_fund_send_fund_senddirty()
         reset_balance(self.nodes[1], self.nodes[0].getnewaddress())
@@ -137,6 +138,30 @@ class AvoidReuseTest(BitcoinTestFramework):
         # Unload temp wallet
         self.nodes[1].unloadwallet(tempwallet)
 
+    def test_change_remains_change(self, node):
+        self.log.info("Test that change doesn't turn into non-change when spent")
+
+        reset_balance(node, node.getnewaddress())
+        addr = node.getnewaddress()
+        txid = node.sendtoaddress(addr, 1)
+        out = node.listunspent(minconf=0, query_options={'minimumAmount': 2})
+        assert_equal(len(out), 1)
+        assert_equal(out[0]['txid'], txid)
+        changeaddr = out[0]['address']
+
+        # Make sure it's starting out as change as expected
+        assert node.getaddressinfo(changeaddr)['ischange']
+        for logical_tx in node.listtransactions():
+            assert logical_tx.get('address') != changeaddr
+
+        # Spend it
+        reset_balance(node, node.getnewaddress())
+
+        # It should still be change
+        assert node.getaddressinfo(changeaddr)['ischange']
+        for logical_tx in node.listtransactions():
+            assert logical_tx.get('address') != changeaddr
+
     def test_fund_send_fund_senddirty(self):
         '''
         Test the same as test_fund_send_fund_send, except send the 10 BTC with