ReadOnlyCollection<string> with private backing field throws exception on NullabilityInfoContext when trying to add migration

Adding a Migration throws 'System.InvalidOperationException'

After adding a new public property with a private backing field to the model, the create and drop apis (context.Database.EnsureDeleted()/context.Database.EnsureCreated()) produce the expected database and table. But trying to add a new migration throws the following:

dotnet ef migrations add SampleMigration
Build started...
Build succeeded.
System.InvalidOperationException: Cannot scaffold C# literals of type 'System.Reflection.NullabilityInfoContext'. The provider should implement CoreTypeMapping.GenerateCodeLiteral to support using it at design time.
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.UnknownLiteral(Object value)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.<Fragment>g__AppendMethodCall|57_0(IMethodCallCodeFragment current, <>c__DisplayClass57_0&)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.Fragment(IMethodCallCodeFragment fragment, Int32 indent)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateAnnotations(String builderName, IAnnotatable annotatable, IndentedStringBuilder stringBuilder, Dictionary`2 annotations, Boolean inChainedCall, Boolean leadingNewline, MethodInfo hasAnnotationMethodInfo)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.Generate(String modelBuilderName, IModel model, IndentedStringBuilder stringBuilder)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpMigrationsGenerator.GenerateMetadata(String migrationNamespace, Type contextType, String migrationName, String migrationId, IModel targetModel)
   at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.ScaffoldMigration(String migrationName, String rootNamespace, String subNamespace, String language, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Cannot scaffold C# literals of type 'System.Reflection.NullabilityInfoContext'. The provider should implement CoreTypeMapping.GenerateCodeLiteral to support using it at design time.

Sample code

Please find the minimum code project here:

https://github.com/Red-F/EfCoreMigrationIssue

This was code added to the model

    public IReadOnlyCollection<string> Uids => _uids.ToList();
    private List<string> _uids = [];
    
    public void AddUids(IEnumerable<string> uids)
    {
        _uids.AddRange(uids);
    }
    
    public void RemoveUids(IEnumerable<string> uids)
    {
        foreach (var uid in uids)
        {
            _uids.Remove(uid);
        }
    }

Stack traces

See above.

Verbose output

dotnet ef --verbose migrations add SampleMigration
Using project '/home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj'.
Using startup project '/home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj'.
dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/tmp/tmpw9FrlF.tmp /verbosity:quiet /nologo /home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj
dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/tmp/tmp0ai4Yq.tmp /verbosity:quiet /nologo /home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj
Build started...
dotnet build /home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj /verbosity:quiet /nologo /p:PublishAot=false

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:01.88

Build succeeded.
dotnet exec --depsfile /home/fred/projects/EfCoreMigrationIssue/bin/Debug/net8.0/EfCoreMigrationIssue.deps.json --additionalprobingpath /home/fred/.nuget/packages --runtimeconfig /home/fred/projects/EfCoreMigrationIssue/bin/Debug/net8.0/EfCoreMigrationIssue.runtimeconfig.json /home/fred/.dotnet/tools/.store/dotnet-ef/9.0.0-rc.1.24451.1/dotnet-ef/9.0.0-rc.1.24451.1/tools/net8.0/any/tools/netcoreapp2.0/any/ef.dll migrations add SampleMigration --assembly /home/fred/projects/EfCoreMigrationIssue/bin/Debug/net8.0/EfCoreMigrationIssue.dll --project /home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj --startup-assembly /home/fred/projects/EfCoreMigrationIssue/bin/Debug/net8.0/EfCoreMigrationIssue.dll --startup-project /home/fred/projects/EfCoreMigrationIssue/EfCoreMigrationIssue.csproj --project-dir /home/fred/projects/EfCoreMigrationIssue/ --root-namespace EfCoreMigrationIssue --language C# --framework net8.0 --nullable --working-dir /home/fred/projects/EfCoreMigrationIssue --verbose
Using assembly 'EfCoreMigrationIssue'.
Using startup assembly 'EfCoreMigrationIssue'.
Using application base '/home/fred/projects/EfCoreMigrationIssue/bin/Debug/net8.0'.
Using working directory '/home/fred/projects/EfCoreMigrationIssue'.
Using root namespace 'EfCoreMigrationIssue'.
Using project directory '/home/fred/projects/EfCoreMigrationIssue/'.
Remaining arguments: .
Finding DbContext classes...
Finding IDesignTimeDbContextFactory implementations...
Finding DbContext classes in the project...
Found DbContext 'DemoDbContext'.
Finding application service provider in assembly 'EfCoreMigrationIssue'...
Finding Microsoft.Extensions.Hosting service provider...
Using environment 'Development'.
Using application service provider from Microsoft.Extensions.Hosting.
Using context 'DemoDbContext'.
Finding design-time services referenced by assembly 'EfCoreMigrationIssue'...
Finding design-time services referenced by assembly 'EfCoreMigrationIssue'...
No referenced design-time services were found.
Finding design-time services for provider 'Microsoft.EntityFrameworkCore.SqlServer'...
Using design-time services from provider 'Microsoft.EntityFrameworkCore.SqlServer'.
Finding IDesignTimeServices implementations in assembly 'EfCoreMigrationIssue'...
No design-time services were found.
System.InvalidOperationException: Cannot scaffold C# literals of type 'System.Reflection.NullabilityInfoContext'. The provider should implement CoreTypeMapping.GenerateCodeLiteral to support using it at design time.
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.UnknownLiteral(Object value)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.<Fragment>g__AppendMethodCall|57_0(IMethodCallCodeFragment current, <>c__DisplayClass57_0&)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.Fragment(IMethodCallCodeFragment fragment, Int32 indent)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateAnnotations(String builderName, IAnnotatable annotatable, IndentedStringBuilder stringBuilder, Dictionary`2 annotations, Boolean inChainedCall, Boolean leadingNewline, MethodInfo hasAnnotationMethodInfo)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.Generate(String modelBuilderName, IModel model, IndentedStringBuilder stringBuilder)
   at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpMigrationsGenerator.GenerateMetadata(String migrationNamespace, Type contextType, String migrationName, String migrationId, IModel targetModel)
   at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.ScaffoldMigration(String migrationName, String rootNamespace, String subNamespace, String language, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace, Boolean dryRun)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Cannot scaffold C# literals of type 'System.Reflection.NullabilityInfoContext'. The provider should implement CoreTypeMapping.GenerateCodeLiteral to support using it at design time.```

### Include provider and version information

EF Core version: 9.0.0-rc.2.24473.5 
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 8.0
Operating system: Linux
IDE: Rider/CLI

@Red-F

I was able to repro this with the following code:

public class Model
{
    public int Id { get; set; }
    public IReadOnlyCollection<string> Uids => _uids.ToList();
    private List<string> _uids = [];
}

public class DemoDbContext : DbContext
{
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Model>().Property(x => x.Uids).HasField("_uids");
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) 
        => optionsBuilder.UseSqlServer();
}

Note the use of Property for a primitive collection. I'm not sure if this should even be allowed; we should discuss. If PrimitiveCollection is used, then the error goes away:

modelBuilder.Entity<Model>().PrimitiveCollection(x => x.Uids).HasField("_uids");

@Red-F Is there a reason for using Property here instead of PrimitiveCollection? (I recognize it's not clear that PrimitiveCollection should be used here.)

Move NonNullableConventionState to CoreAnnotationNames

@ajcvickers

@ajcvickers Why do we do the things that we do? A long time ago I saw a video where you discussed/explained this 'defensive copy' pattern. I liked that. A lot, because I think we need to make it as difficult as possible for ourselves to unintentionally make mistakes. So I use IReadOnlyCollection properties with a backing field of List everywhere.

SInce I like my code to be predictable for future me or new readers, that means I use IReadOnlyCollection<string> as well. Just to have no surprises for readers/reviewers.

I guess the same applies to the model configuration. Just predictably repeated configuration for all the collections. And to be honest, I also was not aware of .PrimitiveCollection(x => x.property). Even after reading your comment it took some effort to find it!

I was able to get it working using a workaround like

        builder.Property(x => x.Uids).HasField("_uids")
            .HasConversion(
                v => JsonConvert.SerializeObject(v, (JsonSerializerSettings?)null),
                v => JsonConvert.DeserializeObject<List<string>>(v, (JsonSerializerSettings?)null)!,
                ReadOnlyCollectionValueComparer<string>.Create());

but my extensive reading of the online documentation (age will teach a person that reading documentation is a GOOD thing) had me convinced that the original code should work. In addition, the create and drop apis do work as intended, it is just that I can't create a migration (bundle).

Move NonNullableConventionState to CoreAnnotationNames

Move NonNullableConventionState to CoreAnnotationNames (#35020)

@roji

Hi @roji, any rough estimate on when may Design 9.0.2 land? This issue is keeping us from upgrading to EF 9.

Move NonNullableConventionState to CoreAnnotationNames (#35359)

@bbascarevic

@bbascarevic mid-Feb.

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ReadOnlyCollection<string> with private backing field throws exception on NullabilityInfoContext when trying to add migration #34996

Adding a Migration throws 'System.InvalidOperationException'

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ReadOnlyCollection<string> with private backing field throws exception on NullabilityInfoContext when trying to add migration #34996

Description

Adding a Migration throws 'System.InvalidOperationException'

Sample code

Stack traces

Verbose output

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ajcvickers commented on Oct 30, 2024

Red-F commented on Oct 31, 2024

14 remaining items

bbascarevic commented on Jan 6, 2025

roji commented on Jan 16, 2025

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