Add equals check and diff for contractAsJson

core/src/main/java/io/bisq/core/payment/payload/PaymentAccountPayload.java

@@ -24,6 +24,9 @@ import lombok.Getter;
 import lombok.ToString;
 import lombok.extern.slf4j.Slf4j;
 
+// That class is used in the contract for creating the contract json. Any change will break the contract.
+// If a field gets added it need to be be annotated with @JsonExclude (excluded from contract). 
+
 @Getter
 @EqualsAndHashCode
 @ToString

core/src/main/java/io/bisq/core/trade/Contract.java

@@ -29,12 +29,15 @@ import io.bisq.core.proto.CoreProtoResolver;
 import io.bisq.generated.protobuffer.PB;
 import io.bisq.network.p2p.NodeAddress;
 import lombok.Value;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
 import org.bitcoinj.core.Coin;
 
 import javax.annotation.Nullable;
 
 import static com.google.common.base.Preconditions.checkArgument;
 
+@Slf4j
 @Value
 public final class Contract implements NetworkPayload {
     private final OfferPayload offerPayload;
@@ -210,6 +213,25 @@ public final class Contract implements NetworkPayload {
         return Price.valueOf(offerPayload.getCurrencyCode(), tradePrice);
     }
 
+    public void printDiff(@Nullable String peersContractAsJson) {
+        final String json = Utilities.objectToJson(this);
+        String diff = StringUtils.difference(json, peersContractAsJson);
+        if (!diff.isEmpty()) {
+            log.warn("Diff of both contracts: \n" + diff);
+            log.warn("\n\n------------------------------------------------------------\n"
+                    + "Contract as json\n"
+                    + json
+                    + "\n------------------------------------------------------------\n");
+
+            log.warn("\n\n------------------------------------------------------------\n"
+                    + "Peers contract as json\n"
+                    + peersContractAsJson
+                    + "\n------------------------------------------------------------\n");
+        } else {
+            log.debug("Both contracts are the same");
+        }
+    }
+
     @Override
     public String toString() {
         return "Contract{" +

core/src/main/java/io/bisq/core/trade/protocol/tasks/seller_as_taker/SellerAsTakerSignAndPublishDepositTx.java

@@ -124,6 +124,7 @@ public class SellerAsTakerSignAndPublishDepositTx extends TradeTask {
                     });
             trade.setDepositTx(depositTx);
         } catch (Throwable t) {
+            trade.getContract().printDiff(processModel.getTradingPeer().getContractAsJson());
             failed(t);
         }
     }

core/src/main/java/io/bisq/core/trade/protocol/tasks/taker/TakerVerifyAndSignContract.java

@@ -97,11 +97,14 @@ public class TakerVerifyAndSignContract extends TradeTask {
             );
             String contractAsJson = Utilities.objectToJson(contract);
             log.trace("Contract as json:{}", contractAsJson);
+
+            contract.printDiff(processModel.getTradingPeer().getContractAsJson());
+            checkArgument(contractAsJson.equals(processModel.getTradingPeer().getContractAsJson()), "Contracts are not matching");
+
             String signature = Sig.sign(processModel.getKeyRing().getSignatureKeyPair().getPrivate(), contractAsJson);
             trade.setContract(contract);
             trade.setContractAsJson(contractAsJson);
             trade.setTakerContractSignature(signature);
-
             try {
                 checkNotNull(maker.getPubKeyRing(), "maker.getPubKeyRing() must nto be null");
                 Sig.verify(maker.getPubKeyRing().getSignaturePubKey(),