DbContext scaffold missing IndexerProperty for M2M relation after upgrading from EF Core 6 to EF Core 8

[stefioan]

Bug description

We recently upgraded from EF Core 6 to EF Core 8, and we realised that we are missing an IndexerProperty in scaffolded DBContext for many to many relation.

DB Context code snippet:

 entity.HasMany(d => d.AnnualValues).WithMany(p => p.AcademicYears)
     .UsingEntity<Dictionary<string, object>>(
         "AnnualValueAcademicYearMapping",
         r => r.HasOne<AnnualValue>().WithMany()
             .HasForeignKey("LearnAimRef", "EffectiveFrom")
             .HasConstraintName("FK_dbo_AnnualValueAcademicYearMapping_AnnualValue"),
         l => l.HasOne<AcademicYearLookup>().WithMany()
             .HasForeignKey("AcademicYear")
             .HasConstraintName("FK_dbo_AnnualValueAcademicYearMapping_AcademicYear_Lookup"),
         j =>
         {
             j.HasKey("AcademicYear", "LearnAimRef", "EffectiveFrom").HasName("PK_dbo_AnnualValueAcademicYearMapping");
             j.ToTable("AnnualValue_AcademicYear_Mapping", "dbo");
             j.IndexerProperty<string>("AcademicYear")
                 .HasMaxLength(4)
                 .IsUnicode(false);
             j.IndexerProperty<string>("LearnAimRef")
                 .HasMaxLength(8)
                 .IsUnicode(false);
	    
             // Manually added in EF 8.0.12
             j.IndexerProperty<DateOnly>("EffectiveFrom").HasColumnType("date");
         }); 

The j.IndexerProperty("EffectiveFrom").HasColumnType("date"); is not automatically generated which is causing failures, so it needs to be added manually.

Unit test error message:
System.InvalidOperationException : The relationship from 'AnnualValueAcademicYearMapping (Dictionary<string, object>)' to 'AnnualValue' with foreign key properties {'LearnAimRef' : string, 'EffectiveFrom' : int} cannot target the primary key {'LearnAimRef' : string, 'EffectiveFrom' : DateOnly} because it is not compatible. Configure a principal key or a set of foreign key properties with compatible types for this relationship.

We couldn't find anything in the documentation, but there was a similar issue in EF Core 7 that has been resolved #32936 . Can you please advise? Thanks in advance.

Your code

[dbo].[AnnualValue](
    [LearnAimRef]   VARCHAR (8)    NOT NULL,
    [EffectiveFrom] DATE           NOT NULL,
CONSTRAINT [PK_dbo_AnnualValue] PRIMARY KEY CLUSTERED ([LearnAimRef] ASC, [EffectiveFrom] ASC) WITH (FILLFACTOR = 90))

[dbo].[AcademicYear_Lookup](
	[AcademicYear] [varchar](4) NOT NULL,
	[AcademicYearDesc] [varchar](150) NULL,
	[AcademicYearDesc2] [varchar](100) NULL,
    CONSTRAINT [PK_dbo_AcademicYear_Lookup] PRIMARY KEY ([AcademicYear]))

[dbo].[AnnualValue_AcademicYear_Mapping] (
    [AcademicYear]                  VARCHAR (4)    NOT NULL,
    [LearnAimRef]                   VARCHAR (8)    NOT NULL,
    [EffectiveFrom]                 DATE           NOT NULL,
    CONSTRAINT [PK_dbo_AnnualValueAcademicYearMapping] PRIMARY KEY CLUSTERED ([AcademicYear] ASC, [LearnAimRef] ASC, [EffectiveFrom] ASC) WITH (FILLFACTOR = 90),
    CONSTRAINT [FK_dbo_AnnualValueAcademicYearMapping_AnnualValue] FOREIGN KEY ([LearnAimRef],  [EffectiveFrom]) REFERENCES  [dbo].[AnnualValue] ([LearnAimRef], [EffectiveFrom]) ON DELETE CASCADE,
    CONSTRAINT [FK_dbo_AnnualValueAcademicYearMapping_AcademicYear_Lookup] FOREIGN KEY ([AcademicYear]) REFERENCES  [dbo].[AcademicYear_Lookup] ([AcademicYear])  ON DELETE CASCADE
    );

Stack traces

Verbose output

EF Core version

8.0.12

Database provider

Microsoft.EntityFrameworkCore.SqlServer

Target framework

.Net 8.0

Operating system

Windows 11

IDE

Visual Studio 2022 17.12.3

[AndriySvyryd]

Could you also include the declarations of the related entity types and preferably put together a small runnable project?

[stefioan]

Of course, I have created a small project similar to the actual implementation so you should be able to find everything you need there.
EntityFrameworkIssue.zip