EF Core Remove-Migration error: Object reference not set to an instance of an object

Question

Since I started using EF core 3.0, I have been having a null reference exception any time I want to revert a migration. Add migration is added without any error, but running remove migration, I get a null reference exception. Though the migration file is removed, but the content of the migration in the ContextModelSnapshot.cs file is not removed, I suppose this will be due to the null reference exception that didn't allow the remove migration process complete successfully.

Note: I also do not have the HasComment in any of my entity framework configuration.

Anyone knows how I can resolve this error.

System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.Literal(String value) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GeneratePropertyAnnotations(IProperty property, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateProperty(String builderName, IProperty property, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateProperties(String builderName, IEnumerable1 properties, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateEntityType(String builderName, IEntityType entityType, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.GenerateEntityTypes(String builderName, IReadOnlyList1 entityTypes, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpSnapshotGenerator.Generate(String builderName, IModel model, IndentedStringBuilder stringBuilder) at Microsoft.EntityFrameworkCore.Migrations.Design.CSharpMigrationsGenerator.GenerateSnapshot(String modelSnapshotNamespace, Type contextType, String modelSnapshotName, IModel model) at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.RemoveMigration(String projectDir, String rootNamespace, Boolean force, String language) at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.RemoveMigration(String contextType, Boolean force) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.RemoveMigrationImpl(String contextType, Boolean force) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.RemoveMigration.<>c__DisplayClass0_0.<.ctor>b__0() at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.b__0() at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action) Object reference not set to an instance of an object.

Wladyslaw Wladyslaw · Accepted Answer · 2020-01-30T16:09:46

Don't sure if the question is actual for now, but I had the same problem when i've updated from EF core 2.x to 3.x. There's some breaking change in EF Core 3.0:

https://docs.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#microsoftentityframeworkcoredesign-is-now-a-developmentdependency-package

I solve my issue by deleting that package reference and using Microsoft.EntityFrameworkCore.Tools 3.1.1 instead.

EF Core Remove-Migration error: Object reference not set to an instance of an object

1 Answers