Revert back to original transaction if payjoined tx does not work

BTCPayServer/Controllers/WalletsController.PSBT.cs

@@ -209,7 +209,8 @@ namespace BTCPayServer.Controllers
                         {
                             Severity = StatusMessageModel.StatusSeverity.Info,
                             AllowDismiss = false,
-                                Html = "This transaction has been coordinated between the receiver and you to create a <a href='https://en.bitcoin.it/wiki/PayJoin' target='_blank'>payjoin transaction</a> by adding inputs from the receiver. The amount being sent may appear higher but is in fact the same"
+                            Html =
+                                $"This transaction has been coordinated between the receiver and you to create a <a href='https://en.bitcoin.it/wiki/PayJoin' target='_blank'>payjoin transaction</a> by adding inputs from the receiver. The amount being sent may appear higher but is in fact the same"
                         });
                         return newPSBT;
                     }
@@ -225,12 +226,14 @@ namespace BTCPayServer.Controllers
             [ModelBinder(typeof(WalletIdModelBinder))]
             WalletId walletId, string psbt = null, 
             string signingKey = null,
-            string signingKeyPath = null)
+            string signingKeyPath = null,
+            string originalPsbt = null)
         {
             var network = NetworkProvider.GetNetwork<BTCPayNetwork>(walletId.CryptoCode);
             var vm = new WalletPSBTReadyViewModel() { PSBT = psbt };
             vm.SigningKey = signingKey;
             vm.SigningKeyPath = signingKeyPath;
+            vm.OriginalPSBT = originalPsbt;
             var derivationSchemeSettings = GetDerivationSchemeSettings(walletId);
             if (derivationSchemeSettings == null)
                 return NotFound();
@@ -351,7 +354,7 @@ namespace BTCPayServer.Controllers
             WalletId walletId, WalletPSBTReadyViewModel vm, string command = null)
         {
             if (command == null)
-                return await WalletPSBTReady(walletId, vm.PSBT, vm.SigningKey, vm.SigningKeyPath);
+                return await WalletPSBTReady(walletId, vm.PSBT, vm.SigningKey, vm.SigningKeyPath, vm.OriginalPSBT);
             PSBT psbt = null;
             var network = NetworkProvider.GetNetwork<BTCPayNetwork>(walletId.CryptoCode);
             try
@@ -367,6 +370,11 @@ namespace BTCPayServer.Controllers
                 vm.GlobalError = "Invalid PSBT";
                 return View(nameof(WalletPSBTReady),vm);
             }
+
+            if (command == "use-original")
+            {
+                return await WalletPSBTReady(walletId, vm.OriginalPSBT, vm.SigningKey, vm.SigningKeyPath);
+            }
             if (command == "broadcast")
             {
                 if (!psbt.IsAllFinalized() && !psbt.TryFinalize(out var errors))
@@ -380,6 +388,17 @@ namespace BTCPayServer.Controllers
                     var broadcastResult = await ExplorerClientProvider.GetExplorerClient(network).BroadcastAsync(transaction);
                     if (!broadcastResult.Success)
                     {
+                        if (!string.IsNullOrEmpty(vm.OriginalPSBT))
+                        {
+                            TempData.SetStatusMessageModel(new StatusMessageModel()
+                            {
+                                Severity = StatusMessageModel.StatusSeverity.Error,
+                                AllowDismiss = false,
+                                Html = $"The payjoin transaction could not be broadcast.<br/>({broadcastResult.RPCCode} {broadcastResult.RPCCodeMessage} {broadcastResult.RPCMessage}).<br/>The transaction has been reverted back to its original format and is ready to be broadcast."
+                            });
+                            return await WalletPSBTReady(walletId, vm.OriginalPSBT, vm.SigningKey, vm.SigningKeyPath);
+                        }
+                        
                         vm.GlobalError = $"RPC Error while broadcasting: {broadcastResult.RPCCode} {broadcastResult.RPCCodeMessage} {broadcastResult.RPCMessage}";
                         return View(nameof(WalletPSBTReady),vm);
                     }

BTCPayServer/Controllers/WalletsController.cs

@@ -692,13 +692,14 @@ namespace BTCPayServer.Controllers
             model.PayJoinEndpointUrl = null;
             if (newPSBT != null)
             {
+                model.OriginalPSBT = model.PSBT;
                 model.PSBT = newPSBT.ToBase64();
                 return View(nameof(WalletSendVault), model);
             }
 
-            return RedirectToWalletPSBTReady(model.PSBT);
+            return RedirectToWalletPSBTReady(model.PSBT, originalPsbt: model.OriginalPSBT);
         }
-        private IActionResult RedirectToWalletPSBTReady(string psbt, string signingKey=  null, string signingKeyPath = null)
+        private IActionResult RedirectToWalletPSBTReady(string psbt, string signingKey=  null, string signingKeyPath = null, string originalPsbt = null)
         {
             var vm = new PostRedirectViewModel()
             {
@@ -707,6 +708,7 @@ namespace BTCPayServer.Controllers
                 Parameters =
                 {
                     new KeyValuePair<string, string>("psbt", psbt),
+                    new KeyValuePair<string, string>("originalPsbt", originalPsbt),
                     new KeyValuePair<string, string>("SigningKey", signingKey),
                     new KeyValuePair<string, string>("SigningKeyPath", signingKeyPath)
                 }
@@ -851,10 +853,11 @@ namespace BTCPayServer.Controllers
             viewModel.PayJoinEndpointUrl = null;
             if (newPSBT != null)
             {
+                viewModel.OriginalPSBT = psbt.ToBase64();
                 viewModel.PSBT = newPSBT.ToBase64();
                 return await SignWithSeed(walletId, viewModel);
             }
-            return RedirectToWalletPSBTReady(psbt.ToBase64(), signingKey.GetWif(network.NBitcoinNetwork).ToString(), rootedKeyPath?.ToString());
+            return RedirectToWalletPSBTReady(psbt.ToBase64(), signingKey.GetWif(network.NBitcoinNetwork).ToString(), rootedKeyPath?.ToString(), viewModel.OriginalPSBT);
         }
 
         private bool PSBTChanged(PSBT psbt, Action act)

BTCPayServer/Models/WalletViewModels/SignWithSeedViewModel.cs

@@ -7,6 +7,7 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class SignWithSeedViewModel
     {
+        public string OriginalPSBT  { get; set; }
         public string PayJoinEndpointUrl { get; set; }
         [Required]
         public string PSBT { get; set; }

BTCPayServer/Models/WalletViewModels/WalletPSBTReadyViewModel.cs

@@ -8,6 +8,7 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class WalletPSBTReadyViewModel
     {
+        public string OriginalPSBT { get; set; }
         public string PSBT { get; set; }
         public string SigningKey { get; set; }
         public string SigningKeyPath { get; set; }

BTCPayServer/Models/WalletViewModels/WalletSendVaultModel.cs

@@ -7,6 +7,7 @@ namespace BTCPayServer.Models.WalletViewModels
 {
     public class WalletSendVaultModel
     {
+        public string OriginalPSBT { get; set; }
         public string WalletId { get; set; }
         public string PSBT { get; set; }
         public string WebsocketPath { get; set; }

BTCPayServer/Views/Wallets/SignWithSeed.cshtml

@@ -27,6 +27,7 @@
     <div class="col-md-10">
         <div asp-validation-summary="All" class="text-danger"></div>
         <form method="post" asp-action="SignWithSeed" asp-route-walletId="@this.Context.GetRouteValue("walletId")">
+            <input type="hidden" asp-for="OriginalPSBT" />
             <input type="hidden" asp-for="PSBT" />
             <input type="hidden" asp-for="PayJoinEndpointUrl" />
             <div class="form-group">

BTCPayServer/Views/Wallets/WalletPSBTReady.cshtml

@@ -137,7 +137,8 @@
         <div class="row">
             <div class="col-lg-12 text-center">
                 <form method="post" asp-action="WalletPSBTReady" asp-route-walletId="@this.Context.GetRouteValue("walletId")">
-                    <input type="hidden" asp-for="PSBT"/>
+                    <input type="hidden" asp-for="PSBT" value="@Model.PSBT"/>
+                    <input type="hidden" asp-for="OriginalPSBT"/>
                     <input type="hidden" asp-for="SigningKey"/>
                     <input type="hidden" asp-for="SigningKeyPath"/>
                     @if (!Model.HasErrors)
@@ -146,6 +147,11 @@
                         <span> or </span>
                     }
                     <button type="submit" class="btn btn-secondary" name="command" value="analyze-psbt">Export as PSBT</button>
+                    @if (!string.IsNullOrEmpty(Model.OriginalPSBT))
+                    {
+                        <span> or </span>
+                        <button type="submit" class="btn btn-secondary" name="command" value="use-original">Skip payjoin</button>
+                    }
                 </form>
             </div>
         </div>

BTCPayServer/Views/Wallets/WalletSendVault.cshtml

@@ -23,6 +23,7 @@
         <form id="broadcastForm" asp-action="WalletSendVault" asp-route-walletId="@this.Context.GetRouteValue("walletId")" method="post" style="display:none;">
             <input type="hidden" id="WalletId" asp-for="WalletId" />
             <input type="hidden" id="PSBT" asp-for="PSBT" value="@Model.PSBT"/>
+            <input type="hidden" id="OriginalPSBT" asp-for="OriginalPSBT" value="@Model.OriginalPSBT"/>
             <input type="hidden" asp-for="WebsocketPath" />
             <input type="hidden" asp-for="PayJoinEndpointUrl" />
         </form>