no clear error when channel opening failing when no room in utxos for change

src/Helpers/CustomExceptions.cs

@@ -22,4 +22,9 @@ public PeerNotOnlineException(string? message = null): base(message) {}
 public class RemoteCanceledFundingException : Exception
 {
    public RemoteCanceledFundingException(string? message = null): base(message) {}
+}
+
+public class NotEnoughRoomInUtxosForFeesException : Exception
+{
+   public NotEnoughRoomInUtxosForFeesException(): base("Not enough room in the UTXOs to cover the fees") {}
 }

src/Helpers/ValidationHelper.cs

@@ -128,7 +128,7 @@ public static void ValidatePubKey(ValidatorEventArgs obj, List<Node> nodes, stri
         }
     }
 
-    public static void validateDestNode(ValidatorEventArgs obj, Node? destNode)
+    public static void ValidateDestNode(ValidatorEventArgs obj, Node? destNode)
     {
         obj.Status = ValidationStatus.Success;
         if (destNode == null)
@@ -138,6 +138,21 @@ public static void validateDestNode(ValidatorEventArgs obj, Node? destNode)
         }
     }
 
+    public static void ValidateAmount(ValidatorEventArgs obj, decimal amount, decimal selectedUtxosAmount, bool isChangeless)
+    {
+        obj.Status = ValidationStatus.Success;
+        if (!isChangeless && amount > selectedUtxosAmount)
+        {
+            obj.Status = ValidationStatus.Error;
+            obj.ErrorText = "The amount is greater than the selected UTXOs amount";
+        }
+        else if (!isChangeless && amount == selectedUtxosAmount)
+        {
+            obj.Status = ValidationStatus.Error;
+            obj.ErrorText = "The amount to send is equal to the selected UTXOs amount, there is no room in the UTXOs for change";
+        }
+    }
+
     /// <summary>
     /// Validated a xpub expect header and lenght size
     /// </summary>

src/Jobs/ChannelOpenJob.cs

@@ -85,7 +85,7 @@ private async Task<bool> LogToChannelRequest(int openRequestId, Exception e, IJo
         try
         {
             var request = await _channelOperationRequestRepository.GetById(openRequestId);
-            if (e is PeerNotOnlineException or RemoteCanceledFundingException)
+            if (e is PeerNotOnlineException or RemoteCanceledFundingException or NotEnoughRoomInUtxosForFeesException)
             {
                 request.StatusLogs.Add(ChannelStatusLog.Error(e.Message));
             }

src/Pages/ChannelRequests.razor

@@ -55,7 +55,7 @@
             <DataGridColumn TItem="ChannelOperationRequest" Field="DestNode.Name" Caption="Remote Node" Sortable="false" Displayable="@IsPendingRequestsColumnVisible(PendingChannelsColumnName.RemoteNode)" PopupFieldColumnSize="ColumnSize.Is12" Editable="true"
                             Validator="ValidationRule.IsAlphanumeric">
                 <EditTemplate>
-                    <Validation Validator="@((ValidatorEventArgs obj) => ValidationHelper.validateDestNode(obj, _selectedDestNode))" @ref="_destNodeValidation">
+                    <Validation Validator="@((ValidatorEventArgs obj) => ValidationHelper.ValidateDestNode(obj, _selectedDestNode))" @ref="_destNodeValidation">
                         <Addons>
                             <Addon AddonType="AddonType.Body">
                                 <TextEdit @bind-Text="@_destNodeName" Placeholder="Type the destination Node public key">
@@ -141,16 +141,22 @@
                 </DisplayTemplate>
                 <EditTemplate>
                     <Validation Validator="@ValidationHelper.ValidateChannelCapacity" @ref="_capacityValidation">
-                        <NumericPicker TValue="decimal" @bind-Value="@_amount" Min="@_minimumChannelCapacity" Max="@_maxChannelCapacity" Decimals="8" Step="0.00001m" CurrencySymbol=" ₿" Disabled="_isChangeless"/>
-                        <FieldHelp>
-                            @{
-                                  decimal amountToShow = _amount < _maxChannelCapacity
-                                      ? _amount
-                                      : _maxChannelCapacity;
-                                  decimal convertedAmount = Math.Round(PriceConversionService.SatToUsdConversion(new Money(amountToShow, MoneyUnit.BTC).Satoshi, _btcPrice), 2);
-                              }
-                              @($"Minimum {_minimumChannelCapacity:f8}. Current amount: {convertedAmount} USD")
+                        <Validation Validator="@((ValidatorEventArgs obj) => ValidationHelper.ValidateAmount(obj, _amount, SelectedUTXOsValue(), _isChangeless))" @ref="_changelessValidation">
+                            <NumericPicker TValue="decimal" @bind-Value="@_amount" Min="@_minimumChannelCapacity" Max="@_maxChannelCapacity" Decimals="8" Step="0.00001m" CurrencySymbol=" ₿" Disabled="_isChangeless">
+                                <Feedback>
+                                    <ValidationError/>
+                                </Feedback>
+                            </NumericPicker>
+                            <FieldHelp>
+                                @{
+                                    decimal amountToShow = _amount < _maxChannelCapacity
+                                        ? _amount
+                                        : _maxChannelCapacity;
+                                    decimal convertedAmount = Math.Round(PriceConversionService.SatToUsdConversion(new Money(amountToShow, MoneyUnit.BTC).Satoshi, _btcPrice), 2);
+                                }
+                                @($"Minimum {_minimumChannelCapacity:f8}. Current amount: {convertedAmount} USD")
                             </FieldHelp>
+                        </Validation>
                     </Validation>
                     <div class="mb-3">
                         <Button Color="Color.Primary" Disabled="@(!_selectedWalletId.HasValue)" Clicked="@OpenCoinSelectionModal">Select Coins</Button> or use
@@ -398,7 +404,7 @@
     TemplatePsbtString="@_templatePSBTString"
     SignedPSBT="@_psbt"/>
 
 <CancelOrRejectPopup
     @ref=@_rejectCancelModalRef
     Title='@(_selectedStatusActionString + " operation: " + _selectedRequest?.Id)'
     Validator="@RejectReasonValidator"
@@ -423,7 +429,8 @@
 
 <UTXOSelectorModal
     @ref="_utxoSelectorModalRef"
-    OnClose="@OnCloseCoinSelectionModal"/>
+    OnClose="@OnCloseCoinSelectionModal"
+    IsWalletWithdrawalValidation="false"/>
 
 @inject IChannelOperationRequestRepository ChannelOperationRequestRepository
 @inject IChannelOperationRequestPSBTRepository ChannelOperationRequestPsbtRepository
@@ -477,6 +484,7 @@
     private Validation? _sourceNodeValidation;
     private Validation? _destNodeValidation;
     private Validation? _capacityValidation;
+    private Validation? _changelessValidation;
 
     private decimal _btcPrice;
 
@@ -653,7 +661,7 @@
     {
         if (LoggedUser == null) return;
 
-        List<Validation?> validators = new() { _destNodeValidation, _sourceNodeValidation, _walletValidation };
+        List<Validation?> validators = new() { _destNodeValidation, _sourceNodeValidation, _walletValidation, _changelessValidation };
         if (_selectedUTXOs.Count == 0)
         {
             validators.Add(_capacityValidation);
@@ -999,6 +1007,11 @@
         {
             _amount = SelectedUTXOsValue();
         }
+        // Most probably, if the user selected all UTXOs is because they want to do a changeless operation
+        if (_selectedUTXOs.Count == _utxoSelectorModalRef.UTXOList.Count)
+        {
+            _isChangeless = true;
+        }
         StateHasChanged();
     }
 

src/Pages/Withdrawals.razor

@@ -408,7 +408,7 @@
     TemplatePsbtString="@_templatePsbtString"
     ApproveRequestDelegate="async () => await ApproveRequestDelegate()"/>
 
 <CancelOrRejectPopup
     @ref="@_rejectCancelModalRef"
     Title='@("Wallet withdrawal:" + _selectedRequest?.Id)'
     Validator="@RejectReasonValidator"
@@ -426,7 +426,7 @@
 <UTXOSelectorModal
     @ref="_utxoSelectorModalRef"
     OnClose="@OnCloseCoinSelectionModal"
-    IsWalletWithdrawalValidation="false"/>
+    IsWalletWithdrawalValidation="true"/>
 
 @inject IToastService ToastService
 @inject IWalletWithdrawalRequestRepository WalletWithdrawalRequestRepository

src/Services/LightningService.cs

@@ -324,6 +324,10 @@ public async Task OpenChannel(ChannelOperationRequest channelOperationRequest)
                                                     o.Value != channelOperationRequest.SatsAmount) ??
                                                 channelfundingTx.Outputs.First();
                                             changeOutput.Value = totalIn - totalOut - totalChangefulFees;
+                                            if (changeOutput.Value < 0)
+                                            {
+                                                throw new NotEnoughRoomInUtxosForFeesException();
+                                            }
 
                                             //We merge changeFixedPSBT with the other PSBT with the change fixed
                                             fundedPSBT = channelfundingTx.CreatePSBT(network).UpdateFrom(fundedPSBT);

src/Shared/UTXOSelectorModal.razor

@@ -100,10 +100,10 @@
                 </div>
             </div>
             <Row Class="mx-1">
                 <Feedback>@String.Join(",", GetUTXOsValues())</Feedback>
             </Row>
             <Row Class="mx-1">
                 <Feedback class="text-danger">@(_validation.Messages != null ? String.Join(",", _validation.Messages) : "")</Feedback>
             </Row>
         </ModalBody>
         <ModalFooter>
@@ -226,17 +226,11 @@
         {
              minimumValue = new Money(Constants.MINIMUM_CHANNEL_CAPACITY_SATS).ToUnit(MoneyUnit.BTC);
         }
-        var maxChannelRegtestValue = new Money(Constants.MAXIMUM_CHANNEL_CAPACITY_SATS_REGTEST).ToUnit(MoneyUnit.BTC);
         if (selectedUTXOsValue < minimumValue)
         {
             e.ErrorText = $"The combined amount of the UTXOs selected must be greater than {minimumValue:f8} BTC";
             e.Status = ValidationStatus.Error;
         }
-        else if (selectedUTXOsValue > maxChannelRegtestValue && network == Network.RegTest && IsWalletWithdrawalValidation)
-        {
-            e.ErrorText = $"The combined amount of the UTXOs selected must be lower than {maxChannelRegtestValue:f8} BTC";
-            e.Status = ValidationStatus.Error;
-        }
         else
         { 
             e.Status = ValidationStatus.Success;