Translate {IPAddress,NetworkAddress}.Parse()

@austindrenski, in addition to all the great translations you’ve recently added, I think we’re missing one: IPAddress.Parse(), which is basically the way to specify an IP address literal…

This should be pretty easy, feel like doing it?

[roji]

NpgsqlEvaluatableExpressionFilter is only meant to specify methods that should not be evaluated on the client, ever. This is a way to avoid evaluating things like DateTime.Now client-side (because time zones may be different), or creating a new GUID client-side (which EF Core would reuse across different database rows, rather than generating a GUID per-row). If you’re interested in reading more about this, see the discussion in https://github.com/aspnet/EntityFrameworkCore/issues/12552#issuecomment-405704458 (including possible upcoming changes).

For our purposes… if the expression contains IPAddress.Parse("127.0.0.1") (with a constant!), then it does make sense for EF Core to evaluate it locally and send the result as a parameter (this is exactly what NpgsqlEvaluatableExpressionFilter is meant to prevent) - there’s no reason to avoid it. The only important bit is to make sure that the parameter really does contain the proper instance of IPAddress - it’s not clear from your comments if that’s happening or not.

If, however, the expression contains a non-constant (e.g. some text column in the database, or a C# variable), then EF Core cannot do client evaluation as above, and you translator should get invoked as expected. Here are some examples:

var text = "127.0.0.1";
// With variable
var blogs = ctx.Blogs.Where(b => b.SomeIp == IPAddress.Parse(text)).ToList();
// With database column
var blogs = ctx.Blogs.Where(b => b.SomeIp == IPAddress.Parse(b.SomeTextColumn)).ToList();

So what you’re seeing is probably simply the expected correct behavior, let me know if otherwise.

[austindrenski]

Ahhh. That all makes sense. I saw some unexpected parameterization and panicked assumed the worst!

What’s interesting (and caught me off-guard) is that both of the following are parameterized:

src.Where(x => x.Inet == IPAddress.Parse("127.0.0.1"));
// WHERE x."Inet" = @__Parse_0

string value = "127.0.0.1"
src.Where(x => x.Inet == IPAddress.Parse(value));
// WHERE x."Inet" = @__Parse_0

If you’re interested in reading more about this, see the discussion in aspnet/EntityFrameworkCore#12552 (comment) (including possible upcoming changes).

Much appreciated!