Unable to update Null as a value to a existing property in case of update

[prasher-ayce]

NEST/Elasticsearch.Net version: NEST 7.10

Elasticsearch version: 7.8.0

Description of the problem including expected versus actual behavior: I am trying to update Null values in a Nullable Datetime field but couldn't able to, Serializer seems to ignore Nulls.
**Things i have tried so far : **

1. inject a custom serializer which includes NULL getting an exception : "Could not load type 'Nest.CartesianPoint' from assembly 'Nest, Version=7.0.0.0";
2. Tried Null value attribute (I am using attribute mapping) turns out i am not able to set a NullValue for Nullable Date time.
3. manually updated mapping in Elastic search using kibana and set a Min Value. No success either
   A clear and concise description of what the bug is.

Steps to reproduce:

1. Create a partial model with some Nullable date fields.
2. Insert values with date fields containing values.
3. Try to update a null next time on those date fields which were set in Step 1.
4. Couldnt able to Set NullValue in attribute mapping for Nullable date field

Expected behavior
A clear and concise description of what you expected to happen.
I want to update Null value in datefields

Provide ConnectionSettings (if relevant):

Provide DebugInformation (if relevant):

[stevejgordon]

@KillerAyce I am investigating the NullValue property on the attribute as I believe I understand what's likely the problem there. Have you tried defining your mapping using the Fluent syntax?

Something like this...

var createIndexResponse = client.Indices.Create("null-sample", c => c
    .Map<Book>(m => m
        .Properties(ps => ps
            .Date(d => d.Name(n => n.PublishDate).NullValue(DateTime.MinValue))
        )
    )
);

So that I can understand the issue better, are you able to provide a small sample of your model and how you are indexing it with NEST? Could you share a sample of how you're setting up the customer serializer which causes the type loading error?

[stevejgordon]

@KillerAyce Further to the above, this comment further explains some of the options for updating with null values.

[prasher-ayce]

@KillerAyce Further to the above, this comment further explains some of the options for updating with null values.

I was able to solve this problem by using CustomJsonNetSerializer.
I was not overriding the following method
protected override void ModifyContractResolver(ConnectionSettingsAwareContractResolver resolver) => resolver.NamingStrategy = new CamelCaseNamingStrategy();
Thanks

Here is my Custom Serializer

[stevejgordon]

Thanks @KillerAyce. I'm very pleased you got this working. Thanks for sharing your final solution. I'll close this now and open a new issue to review the NullValue attribute property for DateTime.