cmd/dropwtxmgr+waddrmgr: handle constraint when resetting synced state

We update the dropwtxmgr utility tool to take into account that the
wallet only stores MaxReorgDepth blocks, which introduced an additional
constraint when updating the wallet's synced state. The constraint
ensures that the previous block exists when updating the wallet's synced
state, but this does not hold for the birthday block since it's the
first block we'll store.

cmd/dropwtxmgr/main.go

@@ -135,7 +135,17 @@ func mainInt() int {
 			return waddrmgr.PutSyncedTo(ns, startBlock)
 		}
 
-		return waddrmgr.PutSyncedTo(ns, &birthdayBlock)
+		// We'll need to remove our birthday block first because it
+		// serves as a barrier when updating our state to detect reorgs
+		// due to the wallet not storing all block hashes of the chain.
+		if err := waddrmgr.DeleteBirthdayBlock(ns); err != nil {
+			return err
+		}
+
+		if err := waddrmgr.PutSyncedTo(ns, &birthdayBlock); err != nil {
+			return err
+		}
+		return waddrmgr.PutBirthdayBlock(ns, birthdayBlock)
 	})
 	if err != nil {
 		fmt.Println("Failed to drop and re-create namespace:", err)

waddrmgr/db.go

@@ -2060,13 +2060,27 @@ func FetchBirthdayBlock(ns walletdb.ReadBucket) (BlockStamp, error) {
 	return block, nil
 }
 
-// putBirthdayBlock stores the provided birthday block to the database.
+// DeleteBirthdayBlock removes the birthday block from the database.
+//
+// NOTE: This does not alter the birthday block verification state.
+func DeleteBirthdayBlock(ns walletdb.ReadWriteBucket) error {
+	bucket := ns.NestedReadWriteBucket(syncBucketName)
+	if err := bucket.Delete(birthdayBlockName); err != nil {
+		str := "failed to remove birthday block"
+		return managerError(ErrDatabase, str, err)
+	}
+	return nil
+}
+
+// PutBirthdayBlock stores the provided birthday block to the database.
 //
 // The block is serialized as follows:
 //   [0:4]   block height
 //   [4:36]  block hash
 //   [36:44] block timestamp
-func putBirthdayBlock(ns walletdb.ReadWriteBucket, block BlockStamp) error {
+//
+// NOTE: This does not alter the birthday block verification state.
+func PutBirthdayBlock(ns walletdb.ReadWriteBucket, block BlockStamp) error {
 	var birthdayBlock [44]byte
 	binary.BigEndian.PutUint32(birthdayBlock[:4], uint32(block.Height))
 	copy(birthdayBlock[4:36], block.Hash[:])

waddrmgr/migrations.go

@@ -354,7 +354,7 @@ func populateBirthdayBlock(ns walletdb.ReadWriteBucket) error {
 
 	// NOTE: The timestamp of the birthday block isn't set since we do not
 	// store each block's timestamp.
-	return putBirthdayBlock(ns, BlockStamp{
+	return PutBirthdayBlock(ns, BlockStamp{
 		Height: birthdayHeight,
 		Hash:   *birthdayHash,
 	})

waddrmgr/migrations_test.go

@@ -247,7 +247,7 @@ func TestMigrationResetSyncedBlockToBirthday(t *testing.T) {
 			Hash: *birthdayHash, Height: birthdayHeight,
 		}
 
-		return putBirthdayBlock(ns, birthdayBlock)
+		return PutBirthdayBlock(ns, birthdayBlock)
 	}
 
 	afterMigration := func(ns walletdb.ReadWriteBucket) error {

waddrmgr/sync.go

@@ -128,7 +128,7 @@ func (m *Manager) BirthdayBlock(ns walletdb.ReadBucket) (BlockStamp, bool, error
 func (m *Manager) SetBirthdayBlock(ns walletdb.ReadWriteBucket,
 	block BlockStamp, verified bool) error {
 
-	if err := putBirthdayBlock(ns, block); err != nil {
+	if err := PutBirthdayBlock(ns, block); err != nil {
 		return err
 	}
 	return putBirthdayBlockVerification(ns, verified)