Merge bitcoin/bitcoin#28609: wallet: Reload watchonly and solvables wallets after migration

4814e4063e674ad9b0a5c7e56059cd6a2bf9b764 test: Check tx metadata is migrated to watchonly (Andrew Chow)
d616d30ea5fdfb897f8375ffd8b9f4536ae7835b wallet: Reload watchonly and solvables wallets after migration (Andrew Chow)
118f2d7d70b584eee7b89e58b5cd2d61c59a9bbf wallet: Copy all tx metadata to watchonly wallet (Andrew Chow)
9af87cf3485ce3fac553a284cde37a35d1085c25 test: Check that a failed wallet migration is cleaned up (Andrew Chow)

Pull request description:

  Some incomplete/incorrect state as a result of migration can be mitigated/cleaned up by simply restarting the migrated wallets. We already do this for a wallet when it is migrated, but we do not for the new watchonly and solvables wallets that may be created. This PR introduces this behavior, in addition to creating those wallets initially without an attached chain.

  While implementing this, I noticed that not all `CWalletTx` metadata was being copied over to the watchonly wallet and so some data, such as time received, was being lost. This PR fixes this as a side effect of not having a chain attached to the watchonly wallet. A test has also been added.

ACKs for top commit:
  ishaanam:
    light code review ACK 4814e4063e674ad9b0a5c7e56059cd6a2bf9b764
  ryanofsky:
    Code review ACK 4814e4063e674ad9b0a5c7e56059cd6a2bf9b764. Just implemented the suggested orderpos, copyfrom, and path set comments since last review
  furszy:
    ACK 4814e406

Tree-SHA512: 0b992430df9f452cb252c2212df8e876613f43564fcd1dc00c6c31fa497adb84dfff6b5ef597590f9b288c5f64cb455f108fcc9b6c9d1fe9eb2c39e7f2c12a89

3 files changed, 92 insertions, 28 deletions

diff --git a/src/wallet/transaction.cpp b/src/wallet/transaction.cpp
index a46846c1d4..4f78fe7520 100644
--- a/src/wallet/transaction.cpp
+++ b/src/wallet/transaction.cpp
@@ -24,4 +24,9 @@ int64_t CWalletTx::GetTxTime() const
     int64_t n = nTimeSmart;
     return n ? n : nTimeReceived;
 }
+
+void CWalletTx::CopyFrom(const CWalletTx& _tx)
+{
+    *this = _tx;
+}
 } // namespace wallet
diff --git a/src/wallet/transaction.h b/src/wallet/transaction.h
index 3b9cde9832..0d0821e857 100644
--- a/src/wallet/transaction.h
+++ b/src/wallet/transaction.h
@@ -334,11 +334,15 @@ public:
     const uint256& GetWitnessHash() const { return tx->GetWitnessHash(); }
     bool IsCoinBase() const { return tx->IsCoinBase(); }
 
+private:
     // Disable copying of CWalletTx objects to prevent bugs where instances get
     // copied in and out of the mapWallet map, and fields are updated in the
     // wrong copy.
-    CWalletTx(CWalletTx const &) = delete;
-    void operator=(CWalletTx const &x) = delete;
+    CWalletTx(const CWalletTx&) = default;
+    CWalletTx& operator=(const CWalletTx&) = default;
+public:
+    // Instead have an explicit copy function
+    void CopyFrom(const CWalletTx&);
 };
 
 struct WalletTxOrderComparator {
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index cb8671c8e7..162d7f9ec7 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -3908,6 +3908,14 @@ bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
     // Check if the transactions in the wallet are still ours. Either they belong here, or they belong in the watchonly wallet.
     // We need to go through these in the tx insertion order so that lookups to spends works.
     std::vector<uint256> txids_to_delete;
+    std::unique_ptr<WalletBatch> watchonly_batch;
+    if (data.watchonly_wallet) {
+        watchonly_batch = std::make_unique<WalletBatch>(data.watchonly_wallet->GetDatabase());
+        // Copy the next tx order pos to the watchonly wallet
+        LOCK(data.watchonly_wallet->cs_wallet);
+        data.watchonly_wallet->nOrderPosNext = nOrderPosNext;
+        watchonly_batch->WriteOrderPosNext(data.watchonly_wallet->nOrderPosNext);
+    }
     for (const auto& [_pos, wtx] : wtxOrdered) {
         if (!IsMine(*wtx->tx) && !IsFromMe(*wtx->tx)) {
             // Check it is the watchonly wallet's
@@ -3916,12 +3924,20 @@ bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
                 LOCK(data.watchonly_wallet->cs_wallet);
                 if (data.watchonly_wallet->IsMine(*wtx->tx) || data.watchonly_wallet->IsFromMe(*wtx->tx)) {
                     // Add to watchonly wallet
-                    if (!data.watchonly_wallet->AddToWallet(wtx->tx, wtx->m_state)) {
-                        error = _("Error: Could not add watchonly tx to watchonly wallet");
+                    const uint256& hash = wtx->GetHash();
+                    const CWalletTx& to_copy_wtx = *wtx;
+                    if (!data.watchonly_wallet->LoadToWallet(hash, [&](CWalletTx& ins_wtx, bool new_tx) EXCLUSIVE_LOCKS_REQUIRED(data.watchonly_wallet->cs_wallet) {
+                        if (!new_tx) return false;
+                        ins_wtx.SetTx(to_copy_wtx.tx);
+                        ins_wtx.CopyFrom(to_copy_wtx);
+                        return true;
+                    })) {
+                        error = strprintf(_("Error: Could not add watchonly tx %s to watchonly wallet"), wtx->GetHash().GetHex());
                         return false;
                     }
+                    watchonly_batch->WriteTx(data.watchonly_wallet->mapWallet.at(hash));
                     // Mark as to remove from this wallet
-                    txids_to_delete.push_back(wtx->GetHash());
+                    txids_to_delete.push_back(hash);
                     continue;
                 }
             }
@@ -3930,6 +3946,7 @@ bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
             return false;
         }
     }
+    watchonly_batch.reset(); // Flush
     // Do the removes
     if (txids_to_delete.size() > 0) {
         std::vector<uint256> deleted_txids;
@@ -4066,6 +4083,10 @@ bool DoMigration(CWallet& wallet, WalletContext& context, bilingual_str& error,
         DatabaseOptions options;
         options.require_existing = false;
         options.require_create = true;
+        options.require_format = DatabaseFormat::SQLITE;
+
+        WalletContext empty_context;
+        empty_context.args = context.args;
 
         // Make the wallets
         options.create_flags = WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET | WALLET_FLAG_DESCRIPTORS;
@@ -4081,8 +4102,14 @@ bool DoMigration(CWallet& wallet, WalletContext& context, bilingual_str& error,
             DatabaseStatus status;
             std::vector<bilingual_str> warnings;
             std::string wallet_name = wallet.GetName() + "_watchonly";
-            data->watchonly_wallet = CreateWallet(context, wallet_name, std::nullopt, options, status, error, warnings);
-            if (status != DatabaseStatus::SUCCESS) {
+            std::unique_ptr<WalletDatabase> database = MakeWalletDatabase(wallet_name, options, status, error);
+            if (!database) {
+                error = strprintf(_("Wallet file creation failed: %s"), error);
+                return false;
+            }
+
+            data->watchonly_wallet = CWallet::Create(empty_context, wallet_name, std::move(database), options.create_flags, error, warnings);
+            if (!data->watchonly_wallet) {
                 error = _("Error: Failed to create new watchonly wallet");
                 return false;
             }
@@ -4112,8 +4139,14 @@ bool DoMigration(CWallet& wallet, WalletContext& context, bilingual_str& error,
             DatabaseStatus status;
             std::vector<bilingual_str> warnings;
             std::string wallet_name = wallet.GetName() + "_solvables";
-            data->solvable_wallet = CreateWallet(context, wallet_name, std::nullopt, options, status, error, warnings);
-            if (status != DatabaseStatus::SUCCESS) {
+            std::unique_ptr<WalletDatabase> database = MakeWalletDatabase(wallet_name, options, status, error);
+            if (!database) {
+                error = strprintf(_("Wallet file creation failed: %s"), error);
+                return false;
+            }
+
+            data->solvable_wallet = CWallet::Create(empty_context, wallet_name, std::move(database), options.create_flags, error, warnings);
+            if (!data->solvable_wallet) {
                 error = _("Error: Failed to create new watchonly wallet");
                 return false;
             }
@@ -4216,47 +4249,69 @@ util::Result<MigrationResult> MigrateLegacyToDescriptor(const std::string& walle
         success = DoMigration(*local_wallet, context, error, res);
     }
 
+    // In case of reloading failure, we need to remember the wallet dirs to remove
+    // Set is used as it may be populated with the same wallet directory paths multiple times,
+    // both before and after reloading. This ensures the set is complete even if one of the wallets
+    // fails to reload.
+    std::set<fs::path> wallet_dirs;
     if (success) {
-        // Migration successful, unload the wallet locally, then reload it.
-        assert(local_wallet.use_count() == 1);
-        local_wallet.reset();
-        res.wallet = LoadWallet(context, wallet_name, /*load_on_start=*/std::nullopt, options, status, error, warnings);
+        // Migration successful, unload all wallets locally, then reload them.
+        const auto& reload_wallet = [&](std::shared_ptr<CWallet>& to_reload) {
+            assert(to_reload.use_count() == 1);
+            std::string name = to_reload->GetName();
+            wallet_dirs.insert(fs::PathFromString(to_reload->GetDatabase().Filename()).parent_path());
+            to_reload.reset();
+            to_reload = LoadWallet(context, name, /*load_on_start=*/std::nullopt, options, status, error, warnings);
+            return to_reload != nullptr;
+        };
+        // Reload the main wallet
+        success = reload_wallet(local_wallet);
+        res.wallet = local_wallet;
         res.wallet_name = wallet_name;
-    } else {
+        if (success && res.watchonly_wallet) {
+            // Reload watchonly
+            success = reload_wallet(res.watchonly_wallet);
+        }
+        if (success && res.solvables_wallet) {
+            // Reload solvables
+            success = reload_wallet(res.solvables_wallet);
+        }
+    }
+    if (!success) {
         // Migration failed, cleanup
         // Copy the backup to the actual wallet dir
         fs::path temp_backup_location = fsbridge::AbsPathJoin(GetWalletDir(), backup_filename);
         fs::copy_file(backup_path, temp_backup_location, fs::copy_options::none);
 
-        // Remember this wallet's walletdir to remove after unloading
-        std::vector<fs::path> wallet_dirs;
-        wallet_dirs.emplace_back(fs::PathFromString(local_wallet->GetDatabase().Filename()).parent_path());
-
-        // Unload the wallet locally
-        assert(local_wallet.use_count() == 1);
-        local_wallet.reset();
-
         // Make list of wallets to cleanup
         std::vector<std::shared_ptr<CWallet>> created_wallets;
+        if (local_wallet) created_wallets.push_back(std::move(local_wallet));
         if (res.watchonly_wallet) created_wallets.push_back(std::move(res.watchonly_wallet));
         if (res.solvables_wallet) created_wallets.push_back(std::move(res.solvables_wallet));
 
         // Get the directories to remove after unloading
         for (std::shared_ptr<CWallet>& w : created_wallets) {
-            wallet_dirs.emplace_back(fs::PathFromString(w->GetDatabase().Filename()).parent_path());
+            wallet_dirs.emplace(fs::PathFromString(w->GetDatabase().Filename()).parent_path());
         }
 
         // Unload the wallets
         for (std::shared_ptr<CWallet>& w : created_wallets) {
-            if (!RemoveWallet(context, w, /*load_on_start=*/false)) {
-                error += _("\nUnable to cleanup failed migration");
-                return util::Error{error};
+            if (w->HaveChain()) {
+                // Unloading for wallets that were loaded for normal use
+                if (!RemoveWallet(context, w, /*load_on_start=*/false)) {
+                    error += _("\nUnable to cleanup failed migration");
+                    return util::Error{error};
+                }
+                UnloadWallet(std::move(w));
+            } else {
+                // Unloading for wallets in local context
+                assert(w.use_count() == 1);
+                w.reset();
             }
-            UnloadWallet(std::move(w));
         }
 
         // Delete the wallet directories
-        for (fs::path& dir : wallet_dirs) {
+        for (const fs::path& dir : wallet_dirs) {
             fs::remove_all(dir);
         }