Data Seeding bug

The problem: cannot explicity initialize values generated on add or update while using data seeding.

Steps to reproduce:

1. Create an entity with generated values on add or update
2. Use data seeding and try to set generated values explicity

Description:

This project was created to demonstrate bug in data seeding when you using generated values. There is entity User with two generated values: Created and Modified. When I'm trying to seed data into table Users and explicity initialize both of generated values, property Modified isn't initialize in migration (unlike Created).

Generated properties attributes:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public DateTime Created { get; set; }

[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime Modified { get; set; }

These rows I want to insert via data seeding (13-th row in DatabaseContext):

modelBuilder.Entity<User>().HasData(new User[]
            {
                new User{Id=1, FirstName="John", LastName="Gold", Age=27, Created=DateTime.Now, Modified=DateTime.Now},
                new User{Id=2, FirstName="Ronald", LastName="Weasley", Age=16, Created=DateTime.Now, Modified=DateTime.Now},
                new User{Id=3, FirstName="Sherlock ", LastName="Holmes", Age=18, Created=DateTime.Now, Modified=DateTime.Now}
            });

I initialize all properties (even Id, Created and Modified) because this article says so.

And here is a migration:

migrationBuilder.InsertData(
      table: "Users",
      columns: new[] { "Id", "Age", "Created", "FirstName", "LastName" },
      values: new object[] { 1L, 27, new DateTime(2020, 4, 16, 12, 13, 34, 841, DateTimeKind.Local).AddTicks(4524), "John", "Gold" });

migrationBuilder.InsertData(
      table: "Users",
      columns: new[] { "Id", "Age", "Created", "FirstName", "LastName" },
      values: new object[] { 2L, 16, new DateTime(2020, 4, 16, 12, 13, 34, 845, DateTimeKind.Local).AddTicks(126), "Ronald", "Weasley" });

migrationBuilder.InsertData(
      table: "Users",
      columns: new[] { "Id", "Age", "Created", "FirstName", "LastName" },
      values: new object[] { 3L, 18, new DateTime(2020, 4, 16, 12, 13, 34, 845, DateTimeKind.Local).AddTicks(199), "Sherlock ", "Holmes" });

As you can see, I specify Modified value, while using data seeding, but this property is not initialized in migration.

Of course, I'm getting exception, when trying to update the database:

Cannot insert the value NULL into column 'Modified', table 'SeedDataBug.dbo.Users'; column does not allow nulls. INSERT fails.
The statement has been terminated.

Technical details:

• EF Core version: 3.1.3
• Database provider: Microsoft.EntityFrameworkCore.SqlServer
• Target framework: .NET Core 3.1
• Operating system: Windows 10
• IDE: Visual Studio 2019 16.4