Microsoft.EntityFrameworkCore.Cosmos "/id" does not match after upgrade to EF 9

[skordesign]

Information

The issue happens after upgrade Microsoft.EntityFrameworkCore.Cosmos to 9.0.0. When downgrade to 8.0.10 the issue doesn't happen.

DbContextConfig

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Gateway>().ToContainer("Gateways").HasPartitionKey(f => f.Id);
    }

Error

When call EnsureCreatedAsync it throws this exception

Unhandled exception. System.ArgumentException: The requested partition key path '/id' does not match existing Container 'Gateways' with partition key path '/Id' (Parameter 'PartitionKey')
   at Microsoft.Azure.Cosmos.DatabaseCore.CreateContainerIfNotExistsAsync(ContainerProperties containerProperties, ThroughputProperties throughputProperties, RequestOptions requestOptions, ITrace trace, CancellationToken cancellationToken)
   at Microsoft.Azure.Cosmos.ClientContextCore.RunWithDiagnosticsHelperAsync[TResult](String containerName, String databaseName, OperationType operationType, ITrace trace, Func`2 task, Tuple`2 openTelemetry, RequestOptions requestOptions, Nullable`1 resourceType)     
   at Microsoft.Azure.Cosmos.ClientContextCore.OperationHelperWithRootTraceAsync[TResult](String operationName, String containerName, String databaseName, OperationType operationType, RequestOptions requestOptions, Func`2 task, Tuple`2 openTelemetry, TraceComponent traceComponent, TraceLevel traceLevel, Nullable`1 resourceType)
   at Microsoft.EntityFrameworkCore.Cosmos.Storage.Internal.CosmosClientWrapper.CreateContainerIfNotExistsOnceAsync(DbContext _, ValueTuple`2 parametersTuple, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.<>c__DisplayClass30_0`2.<<ExecuteAsync>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func`4 operation, Func`4 verifySucceeded, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Cosmos.Storage.Internal.CosmosDatabaseCreator.EnsureCreatedAsync(CancellationToken cancellationToken)

Include provider and version information

EF Core version: 9.0.0
Database provider: Microsoft.EntityFrameworkCore.Cosmos
Target framework: NET 9.0
Operating system: Windows, Linux
IDE: VScode

[JimmyAtSchotte]

I'm having this problem.

In version 8.x.x, the document structure included both Id and id properties, like so:

{
    "Id": "3cf7d6e8-2821-47e0-85e2-08dc6f5438a6",
    "id": "3cf7d6e8-2821-47e0-85e2-08dc6f5438a6",
    "...": "other properties"
}

However, starting with version 9.0.0, the Id property is no longer included in the serialized document:

{
    "id": "3cf7d6e8-2821-47e0-85e2-08dc6f5438a6",
    "...": "other properties"
}

This change specifically affects properties named Id, which are now excluded from the document. It's worth noting:

• Other property names are unaffected and will continue to be serialized as before.
• For example, if a property other than Id is used as the PartitionKey, it will retain its casing and appear as before in the document.

[JimmyAtSchotte]

Found the change in this issue: #34179

Adding .HasShadowId() reverts to old behaviour.

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Gateway>().ToContainer("Gateways").HasPartitionKey(f => f.Id).HasShadowId();
}

[skordesign]

I got another error after add .HasShadowId()

System.InvalidOperationException: Unable to materialize entity instance of type 'Gateway'. No discriminators matched the discriminator value ''.

[JimmyAtSchotte]

I also had .HasNoDiscriminator() since before in my ModelBuilder. TBH I dont recall why adding that. But that works in my context.

I'm on thin ice here, but maybe look into the new method of .HasRootDiscriminatorInJsonId() in your case?

[roji]

Yes, this change was indeed made intentionally in 9.0: standard Cosmos modeling simply has a single lowercase id property, and so the EF primary key property (Id by convention) is now simply mapped to that, removing the needless previous duplication of having both an id and an Id property. This seems like something I missed when documenting the Cosmos breaking changes - we should remedy that - I've opened dotnet/EntityFramework.Docs#4883 to track that.

To summarize, new projects should simply use the default behavior and have their .NET Id property mapped to the Cosmos id property; existing projects are also encouraged to migrate if possible, but can use HasShadowId() to make the EF provider revert to the previous behavior.

@skordesign your error regarding the discriminator value is likely related to another change we made in 9.0, where the discriminator has been renamed from Discriminator to the more standard $type (see breaking change note); this change can also be reverted. See also the 9.0 release notes for Cosmos for more background on these changes. If you're still having trouble please open a new issue with a minimal, runnable repro so that we can understand what you're doing and help.