walletrpc: add new RemoveTransaction endpoint.

The RemoveTransaction endpoint removes the transaction with the
provided txid including all its descendants from the internal wallet.

We still keep watching for the address of the transation in case
the transcation is confirmed nonetheless. This command is particular
useful for neutrino backends because new bitcoind versions do not
reply with an invalid transaction error code when the tx published
fails to be included into the mempool (fullnodes do).

lnrpc/walletrpc/walletkit_grpc.pb.go

@@ -156,6 +156,10 @@ type WalletKitClient interface {
 	// attempt to re-broadcast the transaction on start up, until it enters the
 	// chain.
 	PublishTransaction(ctx context.Context, in *Transaction, opts ...grpc.CallOption) (*PublishResponse, error)
+	// lncli: `wallet removetx`
+	// RemoveTransaction attempts to remove the provided transaction from the
+	// internal transaction store of the wallet.
+	RemoveTransaction(ctx context.Context, in *GetTransactionRequest, opts ...grpc.CallOption) (*RemoveTransactionResponse, error)
 	// SendOutputs is similar to the existing sendmany call in Bitcoind, and
 	// allows the caller to create a transaction that sends to several outputs at
 	// once. This is ideal when wanting to batch create a set of transactions.
@@ -420,6 +424,15 @@ func (c *walletKitClient) PublishTransaction(ctx context.Context, in *Transactio
 	return out, nil
 }
 
+func (c *walletKitClient) RemoveTransaction(ctx context.Context, in *GetTransactionRequest, opts ...grpc.CallOption) (*RemoveTransactionResponse, error) {
+	out := new(RemoveTransactionResponse)
+	err := c.cc.Invoke(ctx, "/walletrpc.WalletKit/RemoveTransaction", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 func (c *walletKitClient) SendOutputs(ctx context.Context, in *SendOutputsRequest, opts ...grpc.CallOption) (*SendOutputsResponse, error) {
 	out := new(SendOutputsResponse)
 	err := c.cc.Invoke(ctx, "/walletrpc.WalletKit/SendOutputs", in, out, opts...)
@@ -641,6 +654,10 @@ type WalletKitServer interface {
 	// attempt to re-broadcast the transaction on start up, until it enters the
 	// chain.
 	PublishTransaction(context.Context, *Transaction) (*PublishResponse, error)
+	// lncli: `wallet removetx`
+	// RemoveTransaction attempts to remove the provided transaction from the
+	// internal transaction store of the wallet.
+	RemoveTransaction(context.Context, *GetTransactionRequest) (*RemoveTransactionResponse, error)
 	// SendOutputs is similar to the existing sendmany call in Bitcoind, and
 	// allows the caller to create a transaction that sends to several outputs at
 	// once. This is ideal when wanting to batch create a set of transactions.
@@ -800,6 +817,9 @@ func (UnimplementedWalletKitServer) ImportTapscript(context.Context, *ImportTaps
 func (UnimplementedWalletKitServer) PublishTransaction(context.Context, *Transaction) (*PublishResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method PublishTransaction not implemented")
 }
+func (UnimplementedWalletKitServer) RemoveTransaction(context.Context, *GetTransactionRequest) (*RemoveTransactionResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method RemoveTransaction not implemented")
+}
 func (UnimplementedWalletKitServer) SendOutputs(context.Context, *SendOutputsRequest) (*SendOutputsResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method SendOutputs not implemented")
 }
@@ -1146,6 +1166,24 @@ func _WalletKit_PublishTransaction_Handler(srv interface{}, ctx context.Context,
 	return interceptor(ctx, in, info, handler)
 }
 
+func _WalletKit_RemoveTransaction_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(GetTransactionRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(WalletKitServer).RemoveTransaction(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/walletrpc.WalletKit/RemoveTransaction",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(WalletKitServer).RemoveTransaction(ctx, req.(*GetTransactionRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 func _WalletKit_SendOutputs_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
 	in := new(SendOutputsRequest)
 	if err := dec(in); err != nil {
@@ -1383,6 +1421,10 @@ var WalletKit_ServiceDesc = grpc.ServiceDesc{
 			MethodName: "PublishTransaction",
 			Handler:    _WalletKit_PublishTransaction_Handler,
 		},
+		{
+			MethodName: "RemoveTransaction",
+			Handler:    _WalletKit_RemoveTransaction_Handler,
+		},
 		{
 			MethodName: "SendOutputs",
 			Handler:    _WalletKit_SendOutputs_Handler,