Inconsistent object mapping behavior when querying using LINQ vs QueryToListAsync

[jeffijoe]

Describe your issue

When using QueryToListAsync<Test> where Test is a record with a primary constructor and [property: Column("some_column")] attributes, it appears the column names specified in the attributes are not being used. If the record does not have a constructor, then it works fine. Additionally, using connection.GetTable<MyType>() to query, then the record with a primary constructor also works. Removing the constructor makes it work with QueryToListAsync.

Steps to reproduce

Using the following as our table/query result type

[Table("test")]
public record Test(
    [property: Column("some_column")]
    string SomeColumn);

When using the following:

await connection.QueryToListAsync<Test>("select some_column from test")

The resulting records will have null in SomeColumn because the [Column] attribute which provides the correct name is not being used.

If instead I do

await db.GetTable<Test>().FirstOrDefaultAsync();

Then the column mapping works and I get the expected value in SomeColumn.

If I change my record to not have a constructor, then everything works fine with QueryToListAsync as well:

[Table("test")]
public record Test
{
    [Column("some_column")]
    public string SomeColumn { get; init; }
}

Is there a difference in how Linq2Db handles object mapping for LINQ-based queries vs SQL-based ones?

Environment details

Linq To DB version: 5.4

Database (with version): Postgres 13

ADO.NET Provider (with version): Npgsql 8.0

Operating system: macOS

.NET Version: 8.0

[MaceWindu]

Yes, currently mapping for raw queries works in a different way. We will unify it in upcoming 6.0 release

[jeffijoe]

Thank you @MaceWindu, and thank you for all the work you guys are doing on Linq2Db, it's an incredible library! 🙏