I'm saving assets through a scheduled job that looks at a folder and maps image names to products. At some point, the implementation was not correct: I believe that an exception before saving the product with its newly assigned assets left the assets in a partially invalid state. So assets were saved to the VPP, but not saved to the product's.

Now, when saving assets to some products using the scheduled job I get the following error:

2017-06-21 12:14:37,419 [84] ERROR BBSCatalyst.Services.ScheduledJobs.AssetIngestionScheduledJob: Attempting to import files for product with code BD489_48 but caught exception
System.Data.SqlClient.SqlException (0x80131904): Cannot insert duplicate key row in object 'dbo.ecfVersionAsset' with unique index 'IDX_ecfVersionAsset_ContentID'. The duplicate key value is (916951, , b216679a-dc90-47ee-927b-b638e66aa6b2).
The statement has been terminated.
   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at EPiServer.Data.Providers.SqlTransientErrorsRetryPolicy.Execute[TResult](Func`1 method)
   at Mediachase.Data.Provider.SqlDataProvider.ExecuteNonExec(DataCommand command)
   at Mediachase.MetaDataPlus.Common.DBHelper.ExecuteNonQuery(String connectionString, CommandType commandType, String commandText, Int32 commandTimeout, DataParameter[] commandParameters)
   at EPiServer.Commerce.Catalog.DataAccess.CatalogContentVersionDB.UpdateContentVersion(List`1 mappingData, DataTable workIdMapping, Boolean publishAction)
   at EPiServer.Commerce.Catalog.Provider.CatalogContentVersionStore.CreateContentVersion(CatalogContentBase content, String currentUser, Boolean publishAction, Boolean skipSetCommonDraft)
   at EPiServer.Commerce.Catalog.Provider.CatalogContentCommitterHandler.SaveVersionInternal(CatalogContentBase content, SaveAction action, String currentUser)
   at EPiServer.Commerce.Catalog.Provider.CatalogContentCommitterHandler.Save(CatalogContentBase content, SaveAction action, String currentUser)
   at EPiServer.Commerce.Catalog.Provider.CatalogContentProvider.Save(IContent content, SaveAction action)
   at EPiServer.Core.Internal.DefaultContentRepository.Save(IContent content, SaveAction action, AccessLevel access)
   at Castle.Proxies.Invocations.IContentRepository_Save.InvokeMethodOnTarget()
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at BBSCatalyst.Integration.Interception.MiniProfilerInterceptor.Intercept(IInvocation invocation) in c:\adir\BBSCatalyst.Integration\Interception\MiniProfilerInterceptor.cs:line 13
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Castle.Proxies.IContentRepositoryProxy.Save(IContent content, SaveAction action, AccessLevel access)
   at BBSCatalyst.Services.ScheduledJobs.AssetIngestionScheduledJob.AddAssetsToProduct(BaseEolProductContent product, AssetInfo[] assetInfos) in c:\adir\BBSCatalyst.Services\ScheduledJobs\AssetIngestionScheduledJob.cs:line 682
   at BBSCatalyst.Services.ScheduledJobs.AssetIngestionScheduledJob.CheckFolder(String importFolderName, Boolean insideUnzippedFolder, List`1& messages) in c:\adir\BBSCatalyst.Services\ScheduledJobs\AssetIngestionScheduledJob.cs:line 182
ClientConnectionId:55be9bf5-c1c7-4700-a4fe-490cf7ddc76b
Error Number:2601,State:1,Class:14

Here's my code:

private void AddAssetsToProduct(BaseEolProductContent product, AssetInfo[] assetInfos)
{
  // Save a new version of the product and get it from the repo
  var contentRepository = ServiceLocator.Current.GetInstance();            
  var writeableProduct = product.CreateWritableClone();
  var productReference = contentRepository.Save(writeableProduct, SaveAction.ForceNewVersion, AccessLevel.NoAccess);
  writeableProduct = contentRepository.Get(productReference).CreateWritableClone();

  // Make a map of assets in the db to assets in the product's media collection, 
  // skipping any assets that don't exist in the db
  GenericFile ignore;
  var currentMedia = writeableProduct.CommerceMediaCollection
    .Where(
      cmcItem => contentRepository.TryGet(cmcItem.AssetLink, out ignore))
    .ToDictionary(
      cmcItem => contentRepository.Get(cmcItem.AssetLink),
      cmcItem => cmcItem);

  // Adding assets to the product's CommerceMediaCollection happens here:
  // Loop through the assets to add. Remove existing media collection items that have
  // the same name. Add the new asset to the product.
  foreach (var assetInfo in assetInfos)
  {
    var currentMediaWithSameName = currentMedia
      .Where(cmItem => cmItem.Key.Name.Equals(assetInfo.Name))
      .Select(cmItem => cmItem.Value);
                
    foreach (var commerceMedia in currentMediaWithSameName)
    {
      writeableProduct.CommerceMediaCollection.Remove(commerceMedia);
    }
    writeableProduct.CommerceMediaCollection
      .Add(new CommerceMedia(assetInfo.Link, string.Empty, assetInfo.Group, 0));
  }

  // Create a dictionary of asset names to asset content references
  var assetDictionary = new Dictionary();
  foreach (var commerceMedia in writeableProduct.CommerceMediaCollection)
  {
    MediaData mediaData;
    var retrievedCollectionItem = contentRepository.TryGet(commerceMedia.AssetLink, out mediaData);
    if (!retrievedCollectionItem || assetDictionary.ContainsKey(mediaData.Name))
      continue;

    assetDictionary.Add(mediaData.Name, commerceMedia.AssetLink);
  }

  // Sort the dictionary by name
  var index = 0;
  var sortedAssetDictionary = assetDictionary.OrderBy(d => d.Key)
    // then create a new dictionary with media and their sort order
    .ToDictionary(kvp => kvp.Value, kvp => index++);

  // Set the sort order for each asset, or place it at the end.
  foreach (var commerceMedia in writeableProduct.CommerceMediaCollection)
  {
    var sortedAssetItem = sortedAssetDictionary.FirstOrDefault(d => d.Key.Equals(commerceMedia.AssetLink));
    commerceMedia.SortOrder = sortedAssetDictionary.ContainsKey(commerceMedia.AssetLink)
      ? sortedAssetItem.Value
      : index;
  }

  // Exception happens here
  contentRepository.Save(writeableProduct, SaveAction.Publish | SaveAction.ForceNewVersion, AccessLevel.NoAccess);         
}

My theory in using SaveAction.ForceNewVersion for the product was that I would get a new version of assets, too, and that would prevent the duplicate key in the ecfAssetVersion table. However, I still get the duplicate key error. 

How can I overwrite or force a new version of the assets?

(I'm on EPiServer Commerce 10.6)