Contains fails translation when the array is a scalar sbuquery

Hi there.

I’m using Npgsql.EntityFrameworkCore.PostgreSQL v. 5.0.2

I have a property on an entity which is a list of UserIds (guids) that have read a specific message.

public string[] ReadByParticipantIds { get; set; }

In an OrderByDescending() call I need to find out whether it contains the specific user calling (to get unread messages at the top).

According to this https://www.npgsql.org/efcore/mapping/array.html#operation-translation I should be able to do this. However, I’ve tried just about anything on that list and I keep getting errors.

.ReadByParticipantIds.Contains(userId) and .ReadByParticipantIds.Any(s => s == userId) Both returns the following error:

Npgsql.PostgresException (0x80004005): 42883: operator does not exist: text = text[]

I’ve even tried dropping the equality and using .Any() with the various LIKE-translated expressions. That just changed the error to text ~~~ text[] instead.

It seems like the mapper tries to create an expression where we do equality on a string and an array of strings. I.e. on the root of the .Contains() or .Any() expression rather on the content.

Am I doing something wrong or is this a plain bug?

I do have a modelbuilder expression on this field, but that should only be activated when the DB is not PostGres. So I doubt that could be the culprit:

modelBuilder.Entity<Message>(b =>
            {
                if (!Database.IsNpgsql())
                {
                    b.Property(p => p.ReadByParticipantIds)
                        .HasConversion(
                            v => string.Join("'", v),
                            v => v.Split(',', StringSplitOptions.RemoveEmptyEntries));
                }
            });

The reason for the above is that I use an in-memory DB for running unit tests.

• Dan

[Dan-True]

@roji It seems to work perfectly 😃 I can remove my ugly hack.

[roji]

Great!