NpgsqlRelationalConnection cast error when using NpgsqlYugabyteDB about efcore.pg HOT 2 CLOSED

I'm not sure why Yugabyte has its own fork of Npgsql, with a special DbConnection of its own; that approach is generally not going to work well with EF (and various other ORMs). For example, you'll also have to override parts of Npgsql.EntityFrameworkCore.PostgreSQL itself so that it doesn't internally instantiate an NpgsqlConnection when given a connection string, but rather a Yugabyte connection. There may be other places as well were such customizations would be needed.

At the end of the day, if Yugabyte created their fork of Npgsql, then it's a different driver, and won't necessarily be compatible with Npgsql; even if we introduce an interface over CloneWith specifically, actual behavioral changes will invariably creep in as Npgsql evolves, which may affect how the EF provider works.

In any case, the dependency on CloneWith specifically is only needed when you use EF to create the database (e.g. with EnsureCreated). If you simply create the database externally (which is what you should be doing anyway in a real app) and refrain from calling EnsureCreated, you shouldn't run into this. Or are you seeing something different?

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Thanks for replying! You are spot on that the error was occurring when I was running migrations. It also seems to fail during normal operations for a subset of queries - for example:

      System.InvalidOperationException: Npgsql-specific type mapping NpgsqlStringTypeMapping being used with non-Npgsql parameter type NpgsqlParameter
         at Npgsql.EntityFrameworkCore.PostgreSQL.Storage.Internal.Mapping.NpgsqlStringTypeMapping.ConfigureParameter(DbParameter parameter)
         at Microsoft.EntityFrameworkCore.Storage.RelationalTypeMapping.CreateParameter(DbCommand command, String name, Object value, Nullable`1 nullable, ParameterDirection direction)

At any rate for my use, the unmodified npgsql driver is excellent. I think this is an issue for the Yugabyte people to resolve, if they want to imo.

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