Check if the token doesn't exist before minting in fill scenarios

2 files changed, 10 insertions, 3 deletions

diff --git a/packages/fill-scenarios/src/fill_scenarios.ts b/packages/fill-scenarios/src/fill_scenarios.ts
index 84c5fbc27..afe42fe32 100644
--- a/packages/fill-scenarios/src/fill_scenarios.ts
+++ b/packages/fill-scenarios/src/fill_scenarios.ts
@@ -238,8 +238,15 @@ export class FillScenarios {
             this._web3Wrapper.getProvider(),
             this._web3Wrapper.getContractDefaults(),
         );
-        const txHash = await erc721Token.mint.sendTransactionAsync(address, tokenId, { from: this._coinbase });
-        await this._web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
+        try {
+            const currentOwner = await erc721Token.ownerOf.callAsync(tokenId);
+            if (currentOwner !== address) {
+                throw new Error(`Token ${tokenAddress}:${tokenId} is already owner by ${currentOwner}`);
+            }
+        } catch (err) {
+            const txHash = await erc721Token.mint.sendTransactionAsync(address, tokenId, { from: this._coinbase });
+            await this._web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
+        }
     }
     private async _increaseERC20BalanceAndAllowanceAsync(
         tokenAddress: string,
diff --git a/packages/order-watcher/src/order_watcher/order_watcher.ts b/packages/order-watcher/src/order_watcher/order_watcher.ts
index 68ef9fab7..c43887b77 100644
--- a/packages/order-watcher/src/order_watcher/order_watcher.ts
+++ b/packages/order-watcher/src/order_watcher/order_watcher.ts
@@ -155,7 +155,7 @@ export class OrderWatcher {
 
         const orderAssetDatas = [signedOrder.makerAssetData, signedOrder.takerAssetData];
         _.each(orderAssetDatas, assetData => {
-            const decodedAssetData = assetProxyUtils.decodeAssetData(assetData);
+            const decodedAssetData = assetProxyUtils.decodeAssetDataOrThrow(assetData);
             if (decodedAssetData.assetProxyId === AssetProxyId.ERC20) {
                 this._collisionResistantAbiDecoder.addERC20Token(decodedAssetData.tokenAddress);
             } else if (decodedAssetData.assetProxyId === AssetProxyId.ERC721) {