Log transaction changes for non-initial rescans

For all rescans except for the initial one when a wallet is first synced
(during reseed, or after process restart), log those transactions that are
changed status from unmined to mined in a block, and any newly-observed
transaction that is added to the wallet.

These later rescans are typically done to fix a problem syncing blocks and/or
transactions, and these transaction hashes should be useful information to
discover what previously went wrong.

wallet/rescan.go

@@ -148,11 +148,30 @@ func (f *RescanFilter) RemoveUnspentOutPoint(op *wire.OutPoint) {
 	delete(f.unspent, *op)
 }
 
+// logRescannedTransactions logs newly-observed transactions that were added
+// by the rescan, and transactions that were changed from unmined to mined.
+// It should only be called if the wallet field logRescannedTransactions is
+// false (just after wallet creation) and will be set true for all later
+// rescans.
+func (w *Wallet) logRescannedTxs(txmgrNs walletdb.ReadBucket, height int32, tx *wire.MsgTx) {
+	txHash := tx.TxHash()
+	haveMined, haveUnmined := w.txStore.ExistsTxMinedOrUnmined(txmgrNs, &txHash)
+	if haveUnmined {
+		log.Infof("Rescan of block %d discovered previously unmined "+
+			"transaction %v", height, &txHash)
+	} else if !haveMined {
+		log.Infof("Rescan of block %d discovered new transaction %v",
+			height, &txHash)
+	}
+}
+
 // saveRescanned records transactions from a rescanned block.  This
 // does not update the network backend with data to watch for future
 // relevant transactions as the rescanner is assumed to handle this
 // task.
-func (w *Wallet) saveRescanned(ctx context.Context, hash *chainhash.Hash, txs []*wire.MsgTx) error {
+func (w *Wallet) saveRescanned(ctx context.Context, hash *chainhash.Hash,
+	txs []*wire.MsgTx, logTxs bool) error {
+
 	const op errors.Op = "wallet.saveRescanned"
 
 	defer w.lockedOutpointMu.Unlock()
@@ -170,6 +189,10 @@ func (w *Wallet) saveRescanned(ctx context.Context, hash *chainhash.Hash, txs []
 		}
 
 		for _, tx := range txs {
+			if logTxs {
+				w.logRescannedTxs(txmgrNs, blockMeta.Height, tx)
+			}
+
 			rec, err := udb.NewTxRecordFromMsgTx(tx, time.Now())
 			if err != nil {
 				return err
@@ -194,6 +217,11 @@ func (w *Wallet) saveRescanned(ctx context.Context, hash *chainhash.Hash, txs []
 func (w *Wallet) rescan(ctx context.Context, n NetworkBackend,
 	startHash *chainhash.Hash, height int32, p chan<- RescanProgress) error {
 
+	w.logRescannedTransactionsMu.Lock()
+	logTxs := w.logRescannedTransactions
+	w.logRescannedTransactions = true
+	w.logRescannedTransactionsMu.Unlock()
+
 	blockHashStorage := make([]chainhash.Hash, maxBlocksPerRescan)
 	rescanFrom := *startHash
 	inclusive := true
@@ -230,7 +258,7 @@ func (w *Wallet) rescan(ctx context.Context, n NetworkBackend,
 		}
 		log.Infof("Rescanning block range [%v, %v]...", height, through)
 		saveRescanned := func(block *chainhash.Hash, txs []*wire.MsgTx) error {
-			return w.saveRescanned(ctx, block, txs)
+			return w.saveRescanned(ctx, block, txs, logTxs)
 		}
 		err = n.Rescan(ctx, rescanBlocks, saveRescanned)
 		if err != nil {

wallet/udb/txquery.go

@@ -276,17 +276,19 @@ func (s *Store) Tx(ns walletdb.ReadBucket, txHash *chainhash.Hash) (*wire.MsgTx,
 
 // ExistsTx checks to see if a transaction exists in the database.
 func (s *Store) ExistsTx(ns walletdb.ReadBucket, txHash *chainhash.Hash) bool {
-	// First, check whether there exists an unmined transaction with this
-	// hash.  Use it if found.
+	mined, unmined := s.ExistsTxMinedOrUnmined(ns, txHash)
+	return mined || unmined
+}
+
+// ExistsTxMinedOrUnmined checks if a transaction is recorded as a mined or
+// unmined transaction.
+func (s *Store) ExistsTxMinedOrUnmined(ns walletdb.ReadBucket, txHash *chainhash.Hash) (mined, unmined bool) {
 	v := existsRawUnmined(ns, txHash[:])
 	if v != nil {
-		return true
+		return false, true
 	}
-
-	// Otherwise, if there exists a mined transaction with this matching
-	// hash, skip over to the newest and begin fetching the msgTx.
 	_, v = latestTxRecord(ns, txHash[:])
-	return v != nil
+	return v != nil, false
 }
 
 // ExistsUTXO checks to see if op refers to an unspent transaction output or a

wallet/wallet.go

@@ -141,12 +141,14 @@ type Wallet struct {
 	lockedOutpoints  map[outpoint]struct{}
 	lockedOutpointMu sync.Mutex
 
-	relayFee                dcrutil.Amount
-	relayFeeMu              sync.Mutex
-	allowHighFees           bool
-	disableCoinTypeUpgrades bool
-	recentlyPublished       map[chainhash.Hash]struct{}
-	recentlyPublishedMu     sync.Mutex
+	relayFee                   dcrutil.Amount
+	relayFeeMu                 sync.Mutex
+	allowHighFees              bool
+	disableCoinTypeUpgrades    bool
+	recentlyPublished          map[chainhash.Hash]struct{}
+	recentlyPublishedMu        sync.Mutex
+	logRescannedTransactions   bool
+	logRescannedTransactionsMu sync.Mutex
 
 	// Internal address handling.
 	ticketAddress    stdaddr.StakeAddress