Firestore : System.ArgumentException: Do not know how to marshal object of type 'Plugin.Firebase.Firestore.FieldValue' to an NSObject

Hi @TobiasBuchholz , I am currently doing some tests about your Firestore “Update” methods, so that I can just “patch” specific fields instead of completely overwriting my object on Firestore.

While this methods works great : myDocumentReference.UpdateDataAsync(updates); , it doesn’t work anymore in a transaction context for some types like IEnumerable, FieldValue, … The error says it cannot “marshal” to an NSObject.

await CrossFirebaseFirestore.Current.RunTransactionAsync(transaction =>
            {
                transaction.UpdateData(myDocumentReference, updates);
                return true;
            });
.....
.....
var batch = CrossFirebaseFirestore.Current.CreateBatch();
batch.UpdateData(myDocumentReference, updates);
await batch.CommitAsync();

StackTrace

System.ArgumentException: Do not know how to marshal object of type 'Plugin.Firebase.Firestore.FieldValue' to an NSObject
  at Foundation.NSArray.From[T] (T[] items, System.Int64 count) [0x0005c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/15.12.0.2/src/Xamarin.iOS/Foundation/NSArray.cs:153 
  at Foundation.NSArray.FromObjects (System.nint count, System.Object[] items) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/15.12.0.2/src/Xamarin.iOS/Foundation/NSArray.cs:136 
  at Foundation.NSDictionary`2[TKey,TValue].FromObjectsAndKeys (System.Object[] objects, System.Object[] keys, System.nint count) [0x00068] in /Library/Frameworks/Xamarin.iOS.framework/Versions/15.12.0.2/src/Xamarin.iOS/Foundation/NSDictionary_2.cs:235 
  at Firebase.CloudFirestore.WriteBatch.UpdateData (System.Collections.Generic.Dictionary`2[TKey,TValue] fields, Firebase.CloudFirestore.DocumentReference document) [0x0002a] in <6138d74f602843c4a14bce9b56ce2700>:0 
  at Plugin.Firebase.iOS.Firestore.WriteBatchWrapper.UpdateData (Plugin.Firebase.Firestore.IDocumentReference document, System.ValueTuple`2[System.String,System.Object][] data) [0x00012] in <af590805f88345db8c9a66cd819c17d8>:0 

Setup

Visual Studio Community 2022 for Mac (17.3) Xamarin.iOS (15.12.0.2) Xamarin.Forms (5.0.0.2478) Plugin.Firebase V1.1.2

Note : I didn’t try on Android yet.

[TobiasBuchholz]

Hi @Kapusch, there was indeed a problem, on android as well. I’ve created a fix for that issue and committed it to the development branch, so it will be available in the next version.

[TobiasBuchholz]

@Kapusch I’ve created a new version 1.1.5 which should fix that issue.