In this repository I aim to analyze an apparent issue where CosmosDB EF Core provider's Where clause implementation
provides an argument to the predicate whose embedded navigation property resolves to null but after materialization of
the query, the entities have their embedded navigation properties materialized as well.
An example code where this could be triggered follows:
var items = appDbContext.Items.Where(i => i.Metadata != null).ToArray();In the above code, the query will return zero items even though an item exists whose Metadata property resolves to an
embedded entity which is not null. Executing the query without the Where clause, the materialized entity will not
have a null for the navigation property value.
This is hard to debug, because the EF Core provider expects an Expression not an actual Func (because it is analyzed
and turned into a SQL query string, not ever actually executed) so it is impossible to make the predicate multi-line and
place a breakpoint within to analyze the arguments one-by-one.
The reproduction in this repository is a simple .NET Core console application bootstrapped using dotnet new console.
The CosmosDB EF Core provider used is the Microsoft.EntityFrameworkCore.Cosmos NuGet package.
I've tried this with both version 2 and version 3 (3.0.0-preview4.19216.3) and I am unable to reproduce, so I must be
missing something which causes this to happen in the real application but is missing in my repro.