Log a warning when Ignore is called on an explicitly configured property or type

[Tarig0]

When ignoring a property that is explicitly used in a key throw an error

Steps to reproduce

modelBuilder.Entity<Counter>().HasAlternateKey(c => new { c.StyleKey, c.IsTest, c.Discriminator });
            modelBuilder.Entity<Counter>().Ignore(c => c.Discriminator);

Further technical details

EF Core version: 2.1.0 rc1 final
Database Provider: Microsoft.EntityFrameworkCore.Sqlite
Operating system: Win10
IDE: Visual Studio 2017 15.7.1

[ajcvickers]

@Tarig0 Why are you both referencing and ignoring the property explicitly?

[Tarig0]

Because I wasn't ignoring the property when I was using the value converter feature, then switched to a private store property, and didn't update the key.

[AndriySvyryd]

Unfortunately if Ignore threw an exception in this case then it would be impossible to remove that property from the model as there's no API for removing keys. But we could log a warning.

[Tarig0]

I think the issue I'm seeing is that the Model is invalid so the program shouldn't be able to continue with the configuration. Not that I want the model to remove the alternate key, but to say hey this alternate key is not valid bad program.

modelBuilder.Entity<Counter>().HasAlternateKey(c => new { c.StyleKey, c.IsTest, c.Discriminator }); //This should be c.StrDiscriminator
            modelBuilder.Entity<Counter>().Ignore(c => c.Discriminator);

[AndriySvyryd]

@Tarig0 I understand that in your case the model configuration is contradicting and doesn't produce the expected model. But Ignore is also used to remove previous configuration. For example that 'HasAlternateKey' call could be in the base context type that you are deriving from and you can't change that code, so calling Ignore would be the only way to remove that key.