Limit number of unconfirmed offers

core/src/main/java/bisq/core/btc/wallet/WalletService.java

@@ -609,6 +609,15 @@ public int getLastBlockSeenHeight() {
         return wallet.getLastBlockSeenHeight();
     }
 
+    /**
+     * Check if there are more than 20 unconfirmed transactions in the chain right now.
+     *
+     * @return true when queue is full
+     */
+    public boolean isUnconfirmedTransactionsLimitHit() {
+        return 20 < getTransactions(true).stream().filter(transaction -> transaction.isPending()).count();
+    }
+
     public Set<Transaction> getTransactions(boolean includeDead) {
         return wallet.getTransactions(includeDead);
     }

core/src/main/java/bisq/core/offer/OpenOfferManager.java

@@ -22,6 +22,7 @@
 import bisq.core.btc.wallet.TradeWalletService;
 import bisq.core.dao.DaoFacade;
 import bisq.core.exceptions.TradePriceOutOfToleranceException;
+import bisq.core.locale.Res;
 import bisq.core.offer.availability.DisputeAgentSelection;
 import bisq.core.offer.messages.OfferAvailabilityRequest;
 import bisq.core.offer.messages.OfferAvailabilityResponse;
@@ -637,6 +638,12 @@ private void handleOfferAvailabilityRequest(OfferAvailabilityRequest request, No
                 availabilityResult = AvailabilityResult.OFFER_TAKEN;
             }
 
+            if (btcWalletService.isUnconfirmedTransactionsLimitHit() || bsqWalletService.isUnconfirmedTransactionsLimitHit()) {
+                errorMessage = Res.get("shared.unconfirmedTransactionsLimitReached");
+                log.warn(errorMessage);
+                availabilityResult = AvailabilityResult.UNKNOWN_FAILURE;
+            }
+
             OfferAvailabilityResponse offerAvailabilityResponse = new OfferAvailabilityResponse(request.offerId,
                     availabilityResult,
                     arbitratorNodeAddress,

core/src/main/java/bisq/core/offer/placeoffer/PlaceOfferProtocol.java

@@ -18,6 +18,7 @@
 package bisq.core.offer.placeoffer;
 
 import bisq.core.offer.placeoffer.tasks.AddToOfferBook;
+import bisq.core.offer.placeoffer.tasks.CheckNumberOfUnconfirmedTransactions;
 import bisq.core.offer.placeoffer.tasks.CreateMakerFeeTx;
 import bisq.core.offer.placeoffer.tasks.ValidateOffer;
 import bisq.core.trade.handlers.TransactionResultHandler;
@@ -71,11 +72,13 @@ public void placeOffer() {
                                 },
                                 log::error);
                     }
+                    model.getOffer().setErrorMessage(errorMessage);
                     errorMessageHandler.handleErrorMessage(errorMessage);
                 }
         );
         taskRunner.addTasks(
                 ValidateOffer.class,
+                CheckNumberOfUnconfirmedTransactions.class,
                 CreateMakerFeeTx.class,
                 AddToOfferBook.class
         );

core/src/main/java/bisq/core/offer/placeoffer/tasks/CheckNumberOfUnconfirmedTransactions.java

@@ -0,0 +1,20 @@
+package bisq.core.offer.placeoffer.tasks;
+
+import bisq.core.locale.Res;
+import bisq.core.offer.placeoffer.PlaceOfferModel;
+
+import bisq.common.taskrunner.Task;
+import bisq.common.taskrunner.TaskRunner;
+
+public class CheckNumberOfUnconfirmedTransactions extends Task<PlaceOfferModel> {
+    public CheckNumberOfUnconfirmedTransactions(TaskRunner taskHandler, PlaceOfferModel model) {
+        super(taskHandler, model);
+    }
+
+    @Override
+    protected void run() {
+        if (model.getWalletService().isUnconfirmedTransactionsLimitHit() || model.getBsqWalletService().isUnconfirmedTransactionsLimitHit())
+            failed(Res.get("shared.unconfirmedTransactionsLimitReached"));
+        complete();
+    }
+}

core/src/main/java/bisq/core/trade/TradeManager.java

@@ -439,6 +439,14 @@ public void onOfferRemovedFromRemoteOfferBook(Offer offer) {
     public void checkOfferAvailability(Offer offer,
                                        ResultHandler resultHandler,
                                        ErrorMessageHandler errorMessageHandler) {
+
+        if (btcWalletService.isUnconfirmedTransactionsLimitHit() || bsqWalletService.isUnconfirmedTransactionsLimitHit()) {
+            String errorMessage = Res.get("shared.unconfirmedTransactionsLimitReached");
+            errorMessageHandler.handleErrorMessage(errorMessage);
+            log.warn(errorMessage);
+            return;
+        }
+
         offer.checkOfferAvailability(getOfferAvailabilityModel(offer), resultHandler, errorMessageHandler);
     }
 

core/src/main/resources/i18n/displayStrings.properties

@@ -214,6 +214,7 @@ shared.arbitrator=Arbitrator
 shared.refundAgent=Arbitrator
 shared.refundAgentForSupportStaff=Refund agent
 shared.delayedPayoutTxId=Refund collateral transaction ID
+shared.unconfirmedTransactionsLimitReached=You have too many unconfirmed transactions at the moment. Please try again later.
 
 
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