Enum with explicitly defined schema the same as the default schema will have its schema removed in ModelSnapshot

[erichiller]

Using EF Core 5 and Npgsql 5, I have several enums defined, and all work as expected, except for enums explicitly set to the public schema (which is the default in this case).

Defined as:
Within my DbContext I setup the enum using

NpgsqlConnection.GlobalTypeMapper.MapEnum<Common.Types.USState>( "public.us_state" );
modelBuilder.HasPostgresEnum<Common.Types.USState>( "public", "us_state" );

I also tried setting HasDefaultSchema('public"); but that didn't help.

before running a migration, XxDBContextModelSnapshot.cs will have:

modelBuilder.HasPostgresEnum("public","us_state", new[] { "unknown", "alabama", "etc..." };

upon creating any migration, even an empty one, XxDBContextModelSnapshot.cs will have the schema removed for that enum:

modelBuilder.HasPostgresEnum("us_state", new[] { "unknown", "alabama", "etc..." };

And then if I do not keep correcting XxDBContextModelSnapshot.cs after any migration is generated I will have all my enums be redefined in the generated migration script. And conflicts will occur for the enum in public as it already exists. Whatever writes out the changes seems to not take default schema into account, and will skip the writing if the schema set explicitly is the same as the default. This might be related to #1027 , but I am not sure.

[roji]

Thanks for reporting, there are definitely some bugs around schema-scoped enums in general.

I'll take a look at this together with #930 and #1315.

[pedro-sphericode]

It is possible to trick the migration class by changing the DbContext a little bit.
Let's say that your entities and types (like an enum) must use a schema named "schemaname". You could inform the modelBuilder that a given property will use a specific name, like "schemaname.myenum".

public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options) { }

static ApplicationDbContext() => NpgsqlConnection.GlobalTypeMapper.MapEnum<MyEnum>(); // Maybe we could define the schema name here...

public DbSet<MyEntity> MyEntity { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
	modelBuilder.HasDefaultSchema("schemaname");

	modelBuilder.HasPostgresEnum<MyEnum>("schemaname");

	// This solves the problem, but... There must be a better way!
	// Also, it doesn't work if the schema name contains a hyphen (e.g., "schema-name").
	modelBuilder.Entity<MyEntity>()
		.Property(p => p.SomeProperty)
			.HasColumnType("schemaname.myenum"); // This should be managed by EF+Npg

	base.OnModelCreating(modelBuilder);
}	

Note that I had to add an underscore to the enum name. The migration class will be created as it follows:

migrationBuilder.CreateTable(
	name: "MyEntity",
	schema: "schemaname",
	columns: table => new
	{
		Id = table.Column<int>(type: "integer", nullable: false)
			.Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
		SomeProperty = table.Column<Constants.MyEnum>(type: "schemaname.my_enum", nullable: false)
	},
	constraints: table =>
	{
		table.PrimaryKey("PK_MyEntity", x => x.Id);
	});

Although it works, I think it would be helpful if the framework could handle it. Also, the presented solution will not help you if your schema name contains a hyphen, as it is going to generate a SQL error when updating your database.

Here is a sample project showing the problem:

https://github.com/please-halp/EFCore5-Npgsql-Issue-using-enum-with-schema

[roji]

Duplicate of #2027

[roji]

(fixed for 5.0.11)