Scaffolding: nullablility annotation issues

[smitpatel]

My VS build currently fails with this

4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(634,50,634,59): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(854,96,854,105): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(887,108,887,117): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(889,80,889,110): error CS8604: Possible null reference argument for parameter 'name' in 'DatabaseUniqueConstraint.DatabaseUniqueConstraint(DatabaseTable table, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(925,86,925,95): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(927,58,927,77): error CS8604: Possible null reference argument for parameter 'name' in 'DatabaseIndex.DatabaseIndex(DatabaseTable table, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(1005,59,1005,77): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(1020,63,1020,81): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(1025,68,1025,74): error CS8604: Possible null reference argument for parameter 'name' in 'DatabaseForeignKey.DatabaseForeignKey(DatabaseTable table, string name, DatabaseTable principalTable)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(1027,63,1027,77): error CS8604: Possible null reference argument for parameter 'onDeleteAction' in 'ReferentialAction? SqlServerDatabaseModelFactory.ConvertToReferentialAction(string onDeleteAction)'.
4>D:\code\EntityFrameworkCore\src\EFCore.SqlServer\Scaffolding\Internal\SqlServerDatabaseModelFactory.cs(1051,67,1051,85): error CS8604: Possible null reference argument for parameter 'name' in 'string SqlServerDatabaseModelFactory.DisplayName(string? schema, string name)'.

Source of confusion is this
https://github.com/aspnet/EntityFrameworkCore/blob/e2ba1c8dab28db719f7a58cacba98dabc23390a7/src/EFCore.SqlServer/Scaffolding/Internal/SqlDataReaderExtension.cs#L41-L48

The file is marked as nullable enable so my understanding is T is non-null but then it does not match annotation on method. On the other hand if this method can return null then it is being used to pass argument to a method which does not accept null.

[smitpatel]

cc: @roji

[roji]

Thanks. You're right that there's an issue: GetValueOrDefault is indeed marked to return nullable (with the MaybeNull attribute), and so it's weird that on my machine and on the CI tableName could be passed to DisplayName without a warning. This is somehow related to the GroupBy being performed over the tableName, which somehow makes the compiler regard it as non-nullable.

Any chance you're using a different VS (or especially dotnet SDK) to build, explaining the behavior difference? Are other people on the team also seeing this with VS (or anything else)?

[smitpatel]

VS Int Preview 16.5.0 Preview 2.0 29703.146.master
Whatever preview SDK startvs.cmd sets.