Breaking change in 2.2: Column is null

I just upgraded my projects from ASP.NET Core 2.1 to version 2.2, including all other packages, with one being the Npgsql.EntityFrameworkCore.PostgreSQL package. After I did the upgrade I received an error while running my application. The error was: InvalidCastException: Column is null.

In order to locate the issue I tried to add a new migration. Since I didn’t change the DbContext I expected it to create an empty migration. That was not the case. It created a migration, which changed the type of a column in one table from Guid? to Guid. This also explains the error, because the table contains entries where the value in that column is null, which it didn’t expect.

I have the same Guid? definition in multiple tables and it broke only in this one table. What is different in this table, compared to the other is, that I create an index on the column.

In short I used something like the following snippet in my ModelCreation method in version 2.1:

class MyTable {
  // ...
  public Guid? MyGuidColumn {get;set;}
}


OnModelCreating {
     // ....
     e.HasIndex(p => p.MyGuidColumn).IsUnique(false);
}

In version 2.2 I have to use the following, in order for npgsql to recognize the column as nullable:

OnModelCreating {
     // ....
     e.Property(p => p.MyGuidColumn).IsRequired(false);
     e.HasIndex(p => p.MyGuidColumn).IsUnique(false);
}

I don’t know if this was an intended change, because it was not very intuitive to notice, that creating an Index automatically makes the nullable a not nullable column, if the column isn’t explicitly created using the Property function.

[avin-kavish]

Same issue… Is there a way to identify exactly which column is causing the issue ? Also I’m getting file paths in the stack trace that probably belong to the maintainers like so C:\projects\npgsql\src\Npgsql\NpgsqlDefaultDataReader.cs

[parvezdesignworks]

Even I have face the same issue