Maintenance: Enable nullable references across the solution

[hjgraca]

Summary

C# 8.0 introduced a significant new feature to the language that extends the type system to make a distinction between references that may be null and ones that must not be.
Enabling non-nullability is a radical change, which is why the feature is switched off until we enabled it explicitly

Why is this needed?

Nullability becomes an opt-in feature: a reference will never contain null unless it is explicitly defined as a nullable reference.
Enabling the type system to distinguish between nullable and non-nullable references is going to be a tricky thing to retrofit. C# cannot always guarantee that a non-nullable reference will never contain a null.
However, it can make the guarantee if certain constraints hold, and more generally it will significantly reduce the chances of encountering a NullReferenceException even in cases where it cannot absolutely rule this out.

Which area does this relate to?

Governance

Solution

On each projects .csproj file add inside PropertyGroup the new tag <Nullable>enable</Nullable>

Example:

<PropertyGroup>
  <Nullable>enable</Nullable>
</PropertyGroup>

Acknowledgment

• This request meets Lambda Powertools Tenets