Merge bitcoin/bitcoin#32977: wallet: Remove wallet version and several legacy related functions

60d1042 wallet: Remove unused `WalletFeature` enums (woltx)
66de582 wallet: Remove `CWallet::nWalletVersion` and related functions (woltx)
7cda3d0 wallet: Remove `IsFeatureSupported()` and `CanSupportFeature()` (woltx)
ba01585 wallet: `MigrateToDescriptor` no longer calls `CanSupportFeature` (woltx)
63acee2 wallet: Remove `GetClosestWalletFeature()` (woltx)
e27da31 wallet: Remove `GetVersion()` (woltx)

Pull request description:

  This PR incorporates the suggestion provided by PRabahy and pablomartin4btc in bitcoin/bitcoin#32944 of removing `CWallet::nWalletVersion` and several related functions, such as `SetMinVersion()`, `GetVersion()`, `GetClosestWalletFeature()`, `IsFeatureSupported()`, `CanSupportFeature()`, etc ...

  This field is no longer used in the descriptor wallet and there is still a lot of code related to it, so the changes here provide a good cleanup in the wallet code.

  Built on top of bitcoin/bitcoin#32944

ACKs for top commit:
  maflcko:
    review ACK 60d1042 🐾
  achow101:
    ACK 60d1042
  pablomartin4btc:
    ACK 60d1042

Tree-SHA512: 1a7ad8e15d57df8f66545776e7d178a2cd5312c87769a29770588375e3de5f24247aab9919acf004ed3eca16d08ba595b5f1c7b2b3eef7752e89d9c295624583

Author: achow101

src/wallet/rpc/wallet.cpp

@@ -40,7 +40,7 @@ static RPCHelpMan getwalletinfo()
                     {
                         {
                         {RPCResult::Type::STR, "walletname", "the wallet name"},
-                        {RPCResult::Type::NUM, "walletversion", "the wallet version"},
+                        {RPCResult::Type::NUM, "walletversion", "(DEPRECATED) only related to unsupported legacy wallet, returns the latest version 169900 for backwards compatibility"},
                         {RPCResult::Type::STR, "format", "the database format (only sqlite)"},
                         {RPCResult::Type::NUM, "txcount", "the total number of transactions in the wallet"},
                         {RPCResult::Type::NUM, "keypoolsize", "how many new keys are pre-generated (only counts external keys)"},
@@ -82,16 +82,16 @@ static RPCHelpMan getwalletinfo()
 
     UniValue obj(UniValue::VOBJ);
 
+    const int latest_legacy_wallet_minversion{169900};
+
     size_t kpExternalSize = pwallet->KeypoolCountExternalKeys();
     obj.pushKV("walletname", pwallet->GetName());
-    obj.pushKV("walletversion", pwallet->GetVersion());
+    obj.pushKV("walletversion", latest_legacy_wallet_minversion);
     obj.pushKV("format", pwallet->GetDatabase().Format());
     obj.pushKV("txcount",       (int)pwallet->mapWallet.size());
     obj.pushKV("keypoolsize", (int64_t)kpExternalSize);
+    obj.pushKV("keypoolsize_hd_internal", pwallet->GetKeyPoolSize() - kpExternalSize);
 
-    if (pwallet->CanSupportFeature(FEATURE_HD_SPLIT)) {
-        obj.pushKV("keypoolsize_hd_internal",   (int64_t)(pwallet->GetKeyPoolSize() - kpExternalSize));
-    }
     if (pwallet->IsCrypted()) {
         obj.pushKV("unlocked_until", pwallet->nRelockTime);
     }

src/wallet/scriptpubkeyman.cpp

@@ -624,10 +624,13 @@ std::optional<MigrationData> LegacyDataSPKM::MigrateToDescriptor()
     for (const auto& chain_pair : m_inactive_hd_chains) {
         chains.push_back(chain_pair.second);
     }
+
+    bool can_support_hd_split_feature = m_hd_chain.nVersion >= CHDChain::VERSION_HD_CHAIN_SPLIT;
+
     for (const CHDChain& chain : chains) {
         for (int i = 0; i < 2; ++i) {
             // Skip if doing internal chain and split chain is not supported
-            if (chain.seed_id.IsNull() || (i == 1 && !m_storage.CanSupportFeature(FEATURE_HD_SPLIT))) {
+            if (chain.seed_id.IsNull() || (i == 1 && !can_support_hd_split_feature)) {
                 continue;
             }
             // Get the master xprv

src/wallet/scriptpubkeyman.h

@@ -47,8 +47,6 @@ class WalletStorage
     virtual WalletDatabase& GetDatabase() const = 0;
     virtual bool IsWalletFlagSet(uint64_t) const = 0;
     virtual void UnsetBlankWalletFlag(WalletBatch&) = 0;
-    virtual bool CanSupportFeature(enum WalletFeature) const = 0;
-    virtual void SetMinVersion(enum WalletFeature, WalletBatch* = nullptr) = 0;
     //! Pass the encryption key to cb().
     virtual bool WithEncryptionKey(std::function<bool (const CKeyingMaterial&)> cb) const = 0;
     virtual bool HasEncryptionKeys() const = 0;

src/wallet/test/wallet_tests.cpp

@@ -492,7 +492,6 @@ BOOST_FIXTURE_TEST_CASE(wallet_disableprivkeys, TestChain100Setup)
     const std::shared_ptr<CWallet> wallet = std::make_shared<CWallet>(m_node.chain.get(), "", CreateMockableWalletDatabase());
     LOCK(wallet->cs_wallet);
     wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
-    wallet->SetMinVersion(FEATURE_LATEST);
     wallet->SetWalletFlag(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
     BOOST_CHECK(!wallet->GetNewDestination(OutputType::BECH32, ""));
 }

src/wallet/wallet.cpp

@@ -639,23 +639,6 @@ void CWallet::SetLastBlockProcessed(int block_height, uint256 block_hash)
     WriteBestBlock();
 }
 
-void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch* batch_in)
-{
-    LOCK(cs_wallet);
-    if (nWalletVersion >= nVersion)
-        return;
-    WalletLogPrintf("Setting minversion to %d\n", nVersion);
-    nWalletVersion = nVersion;
-
-    {
-        WalletBatch* batch = batch_in ? batch_in : new WalletBatch(GetDatabase());
-        if (nWalletVersion > 40000)
-            batch->WriteMinVersion(nWalletVersion);
-        if (!batch_in)
-            delete batch;
-    }
-}
-
 std::set<Txid> CWallet::GetConflicts(const Txid& txid) const
 {
     std::set<Txid> result;
@@ -821,9 +804,6 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
             }
         }
 
-        // Encryption was introduced in version 0.4.0
-        SetMinVersion(FEATURE_WALLETCRYPT, encrypted_batch);
-
         if (!encrypted_batch->TxnCommit()) {
             delete encrypted_batch;
             encrypted_batch = nullptr;
@@ -2871,9 +2851,6 @@ std::shared_ptr<CWallet> CWallet::Create(WalletContext& context, const std::stri
     {
         LOCK(walletInstance->cs_wallet);
 
-        // ensure this wallet.dat can only be opened by clients supporting HD with chain split and expects no default key
-        walletInstance->SetMinVersion(FEATURE_LATEST);
-
         // Init with passed flags.
         // Always set the cache upgrade flag as this feature is supported from the beginning.
         walletInstance->InitWalletFlags(wallet_creation_flags | WALLET_FLAG_LAST_HARDENED_XPUB_CACHED);

src/wallet/wallet.h

@@ -321,9 +321,6 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     std::atomic<double> m_scanning_progress{0};
     friend class WalletRescanReserver;
 
-    //! the current wallet version: clients below this version are not able to load the wallet
-    int nWalletVersion GUARDED_BY(cs_wallet){FEATURE_BASE};
-
     /** The next scheduled rebroadcast of wallet transactions. */
     NodeClock::time_point m_next_resend{GetDefaultNextResend()};
     /** Whether this wallet will submit newly created transactions to the node's mempool and
@@ -556,9 +553,6 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     int GetTxBlocksToMaturity(const CWalletTx& wtx) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool IsTxImmatureCoinBase(const CWalletTx& wtx) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    //! check whether we support the named feature
-    bool CanSupportFeature(enum WalletFeature wf) const override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); return IsFeatureSupported(nWalletVersion, wf); }
-
     bool IsSpent(const COutPoint& outpoint) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     // Whether this or any known scriptPubKey with the same single key has been spent.
@@ -588,8 +582,6 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     //! Upgrade DescriptorCaches
     void UpgradeDescriptorCache() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; return true; }
-
     //! Marks destination as previously spent.
     void LoadAddressPreviouslySpent(const CTxDestination& dest) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     //! Appends payment request to destination.
@@ -825,12 +817,6 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
 
     unsigned int GetKeyPoolSize() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    //! signify that a particular wallet feature is now used.
-    void SetMinVersion(enum WalletFeature, WalletBatch* batch_in = nullptr) override;
-
-    //! get the current wallet format (the oldest client version guaranteed to understand this wallet)
-    int GetVersion() const { LOCK(cs_wallet); return nWalletVersion; }
-
     //! Get wallet transactions that conflict with given transaction (spend same outputs)
     std::set<Txid> GetConflicts(const Txid& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 

src/wallet/walletdb.cpp

@@ -199,11 +199,6 @@ bool WalletBatch::WriteOrderPosNext(int64_t nOrderPosNext)
     return WriteIC(DBKeys::ORDERPOSNEXT, nOrderPosNext);
 }
 
-bool WalletBatch::WriteMinVersion(int nVersion)
-{
-    return WriteIC(DBKeys::MINVERSION, nVersion);
-}
-
 bool WalletBatch::WriteActiveScriptPubKeyMan(uint8_t type, const uint256& id, bool internal)
 {
     std::string key = internal ? DBKeys::ACTIVEINTERNALSPK : DBKeys::ACTIVEEXTERNALSPK;
@@ -442,19 +437,6 @@ bool LoadHDChain(CWallet* pwallet, DataStream& ssValue, std::string& strErr)
     return true;
 }
 
-static DBErrors LoadMinVersion(CWallet* pwallet, DatabaseBatch& batch) EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)
-{
-    AssertLockHeld(pwallet->cs_wallet);
-    int nMinVersion = 0;
-    if (batch.Read(DBKeys::MINVERSION, nMinVersion)) {
-        pwallet->WalletLogPrintf("Wallet file version = %d\n", nMinVersion);
-        if (nMinVersion > FEATURE_LATEST)
-            return DBErrors::TOO_NEW;
-        pwallet->LoadMinVersion(nMinVersion);
-    }
-    return DBErrors::LOAD_OK;
-}
-
 static DBErrors LoadWalletFlags(CWallet* pwallet, DatabaseBatch& batch) EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)
 {
     AssertLockHeld(pwallet->cs_wallet);
@@ -1137,8 +1119,6 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
     if (has_last_client) pwallet->WalletLogPrintf("Last client version = %d\n", last_client);
 
     try {
-        if ((result = LoadMinVersion(pwallet, *m_batch)) != DBErrors::LOAD_OK) return result;
-
         // Load wallet flags, so they are known when processing other records.
         // The FLAGS key is absent during wallet creation.
         if ((result = LoadWalletFlags(pwallet, *m_batch)) != DBErrors::LOAD_OK) return result;

src/wallet/walletdb.h

@@ -241,8 +241,6 @@ class WalletBatch
 
     bool WriteOrderPosNext(int64_t nOrderPosNext);
 
-    bool WriteMinVersion(int nVersion);
-
     bool WriteDescriptorKey(const uint256& desc_id, const CPubKey& pubkey, const CPrivKey& privkey);
     bool WriteCryptedDescriptorKey(const uint256& desc_id, const CPubKey& pubkey, const std::vector<unsigned char>& secret);
     bool WriteDescriptor(const uint256& desc_id, const WalletDescriptor& descriptor);

src/wallet/wallettool.cpp

@@ -31,7 +31,6 @@ static void WalletCreate(CWallet* wallet_instance, uint64_t wallet_creation_flag
 {
     LOCK(wallet_instance->cs_wallet);
 
-    wallet_instance->SetMinVersion(FEATURE_LATEST);
     wallet_instance->InitWalletFlags(wallet_creation_flags);
 
     Assert(wallet_instance->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));

src/wallet/walletutil.cpp

@@ -32,20 +32,6 @@ fs::path GetWalletDir()
     return path;
 }
 
-bool IsFeatureSupported(int wallet_version, int feature_version)
-{
-    return wallet_version >= feature_version;
-}
-
-WalletFeature GetClosestWalletFeature(int version)
-{
-    static constexpr std::array wallet_features{FEATURE_LATEST, FEATURE_PRE_SPLIT_KEYPOOL, FEATURE_NO_DEFAULT_KEY, FEATURE_HD_SPLIT, FEATURE_HD, FEATURE_COMPRPUBKEY, FEATURE_WALLETCRYPT, FEATURE_BASE};
-    for (const WalletFeature& wf : wallet_features) {
-        if (version >= wf) return wf;
-    }
-    return static_cast<WalletFeature>(0);
-}
-
 WalletDescriptor GenerateWalletDescriptor(const CExtPubKey& master_key, const OutputType& addr_type, bool internal)
 {
     int64_t creation_time = GetTime();