wallet: remove nWalletMaxVersion

nWalletMaxVersion was used to allow an upgrade to a version only
when the new feature was used. This makes sense for the old
-upgradewallet startup option. But because upgradewallet is now a RPC,
putting off the version bump like this does not make sense. Instead,
immediately upgrading to the given version number makes sense.

src/wallet/scriptpubkeyman.h

@@ -37,7 +37,7 @@ public:
     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, bool = false) = 0;
+    virtual void SetMinVersion(enum WalletFeature, WalletBatch* = nullptr) = 0;
     virtual const CKeyingMaterial& GetEncryptionKey() const = 0;
     virtual bool HasEncryptionKeys() const = 0;
     virtual bool IsLocked() const = 0;

src/wallet/wallet.cpp

@@ -435,21 +435,13 @@ void CWallet::chainStateFlushed(const CBlockLocator& loc)
     batch.WriteBestBlock(loc);
 }
 
-void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch* batch_in, bool fExplicit)
+void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch* batch_in)
 {
     LOCK(cs_wallet);
     if (nWalletVersion >= nVersion)
         return;
-
-    // when doing an explicit upgrade, if we pass the max version permitted, upgrade all the way
-    if (fExplicit && nVersion > nWalletMaxVersion)
-            nVersion = FEATURE_LATEST;
-
     nWalletVersion = nVersion;
 
-    if (nVersion > nWalletMaxVersion)
-        nWalletMaxVersion = nVersion;
-
     {
         WalletBatch* batch = batch_in ? batch_in : new WalletBatch(*database);
         if (nWalletVersion > 40000)
@@ -459,18 +451,6 @@ void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch* batch_in,
     }
 }
 
-bool CWallet::SetMaxVersion(int nVersion)
-{
-    LOCK(cs_wallet);
-    // cannot downgrade below current version
-    if (nWalletVersion > nVersion)
-        return false;
-
-    nWalletMaxVersion = nVersion;
-
-    return true;
-}
-
 std::set<uint256> CWallet::GetConflicts(const uint256& txid) const
 {
     std::set<uint256> result;
@@ -655,7 +635,7 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
         }
 
         // Encryption was introduced in version 0.4.0
-        SetMinVersion(FEATURE_WALLETCRYPT, encrypted_batch, true);
+        SetMinVersion(FEATURE_WALLETCRYPT, encrypted_batch);
 
         if (!encrypted_batch->TxnCommit()) {
             delete encrypted_batch;
@@ -4120,31 +4100,30 @@ const CAddressBookData* CWallet::FindAddressBookEntry(const CTxDestination& dest
 bool CWallet::UpgradeWallet(int version, bilingual_str& error, std::vector<bilingual_str>& warnings)
 {
     int prev_version = GetVersion();
-    int& nMaxVersion = version;
-    if (nMaxVersion == 0) // the -upgradewallet without argument case
+    if (version == 0) // the -upgradewallet without argument case
     {
         WalletLogPrintf("Performing wallet upgrade to %i\n", FEATURE_LATEST);
-        nMaxVersion = FEATURE_LATEST;
-        SetMinVersion(FEATURE_LATEST); // permanently upgrade the wallet immediately
+        version = FEATURE_LATEST;
     } else {
-        WalletLogPrintf("Allowing wallet upgrade up to %i\n", nMaxVersion);
+        WalletLogPrintf("Allowing wallet upgrade up to %i\n", version);
     }
-    if (nMaxVersion < GetVersion())
+    if (version < prev_version)
     {
         error = _("Cannot downgrade wallet");
         return false;
     }
-    SetMaxVersion(nMaxVersion);
 
     LOCK(cs_wallet);
 
     // Do not upgrade versions to any version between HD_SPLIT and FEATURE_PRE_SPLIT_KEYPOOL unless already supporting HD_SPLIT
-    int max_version = GetVersion();
-    if (!CanSupportFeature(FEATURE_HD_SPLIT) && max_version >= FEATURE_HD_SPLIT && max_version < FEATURE_PRE_SPLIT_KEYPOOL) {
+    if (!CanSupportFeature(FEATURE_HD_SPLIT) && version >= FEATURE_HD_SPLIT && version < FEATURE_PRE_SPLIT_KEYPOOL) {
         error = _("Cannot upgrade a non HD split wallet without upgrading to support pre split keypool. Please use version 169900 or no version specified.");
         return false;
     }
 
+    // Permanently upgrade to the version
+    SetMinVersion(GetClosestWalletFeature(version));
+
     for (auto spk_man : GetActiveScriptPubKeyMans()) {
         if (!spk_man->Upgrade(prev_version, version, error)) {
             return false;

src/wallet/wallet.h

@@ -636,9 +636,6 @@ private:
     //! the current wallet version: clients below this version are not able to load the wallet
     int nWalletVersion GUARDED_BY(cs_wallet){FEATURE_BASE};
 
-    //! the maximum wallet format version: memory-only variable that specifies to what version this wallet may be upgraded
-    int nWalletMaxVersion GUARDED_BY(cs_wallet) = FEATURE_BASE;
-
     int64_t nNextResend = 0;
     bool fBroadcastTransactions = false;
     // Local time that the tip block was received. Used to schedule wallet rebroadcasts.
@@ -800,8 +797,8 @@ public:
     const CWalletTx* GetWalletTx(const uint256& hash) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool IsTrusted(const CWalletTx& wtx, std::set<uint256>& trusted_parents) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    //! check whether we are allowed to upgrade (or already support) to the named feature
-    bool CanSupportFeature(enum WalletFeature wf) const override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); return IsFeatureSupported(nWalletMaxVersion, wf); }
+    //! 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); }
 
     /**
      * populate vCoins with vector of available COutputs.
@@ -853,7 +850,7 @@ public:
     //! Upgrade stored CKeyMetadata objects to store key origin info as KeyOriginInfo
     void UpgradeKeyMetadata() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion); return true; }
+    bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; return true; }
 
     /**
      * Adds a destination data tuple to the store, and saves it to disk
@@ -1076,11 +1073,8 @@ public:
 
     unsigned int GetKeyPoolSize() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
-    //! signify that a particular wallet feature is now used. this may change nWalletVersion and nWalletMaxVersion if those are lower
-    void SetMinVersion(enum WalletFeature, WalletBatch* batch_in = nullptr, bool fExplicit = false) override;
-
-    //! change which version we're allowed to upgrade to (note that this does not immediately imply upgrading to that format)
-    bool SetMaxVersion(int nVersion);
+    //! 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; }