Readonly properties are no longer readonly when using backing store

[rangp]

While generating a c# client with kiota version 1.21.0, I noticed that readonly properties are no longer readonly when using a backing store.

My readonly property was generated like this:

public double? AveragePriceGross { get; private set; }

After re-generating the client with a backing store, it now looks like this and I can set the property, even though it is marked as readonly in my api definition

        public double? AveragePriceGross
        {
            get { return BackingStore?.Get<double?>("average_price_gross"); }
            set { BackingStore?.Set("average_price_gross", value); }
        }

I understand that with backing store enabled, one can always change the property by manually changing the value in the underlying store, but I think the behavior should be consistent and the generated properties should either always or never be readonly, independent of whether a backing store is used.

[baywet]

Hi @rangp
Thank you for using kiota and for reaching out.

I'd like to mention that we're operating with a reduced team at the moment, expect delays in responses, thank you for your patience!

This is where it's written

https://github.com/microsoft/kiota/blob/1b9c9f9f6dfd0b873cf158994d2805bb8ff93520/src/Kiota.Builder/Writers/CSharp/CodePropertyWriter.cs#L58

This is where it's being tested

https://github.com/microsoft/kiota/blob/1b9c9f9f6dfd0b873cf158994d2805bb8ff93520/tests/Kiota.Builder.Tests/Writers/CSharp/CodePropertyWriterTests.cs#L107

The only challenge here is that reducing the accessibility of the setter is a source breaking change. So we'll have to have an additional condition to only apply the access modifier when Exclude Backwards Compatible is passed (--ebc).

Is this something you'd like to submit a pull request for provided some guidance?