Nullable object must have a value thrown for a query with DefaultIfEmpty()

Hi,
I am getting error "Nullable object must have a value" using the following scenario:

var categories = from c in dbContext.Set<AMOS_ADDRESSCATEGORY>().AsNoTracking()
                                 select new
                                 {
                                     Id = c.ADDRESSCATEGORYID,
                                     Name = c.DESCRIPTION
                                 };

var addresses = (from address in dbContext.Set<AMOS_ADDRESS>().AsNoTracking()
                                 join c in categories on address.ADDRESSCATEGORYID equals c.Id into aC
                                 from category in aC.DefaultIfEmpty()
                                 select new
                                 {
                                     Id = address.ADDRESSID,
                                     Category = category
                                 }).ToArray();

The above scenarion works pefectly using EF Standard and works in EF Core if I change to:

var addresses = (from address in dbContext.Set<AMOS_ADDRESS>().AsNoTracking()
                                 **join c in dbContext.Set<AMOS_ADDRESSCATEGORY>().AsNoTracking()** 
                                on address.ADDRESSCATEGORYID equals c.ADDRESSCATEGORYID into aC
                                 from category in aC.DefaultIfEmpty()
                                 select new
                                 {
                                     Id = address.ADDRESSID,
                                     Category = category
                                 }).ToArray();

Can you help me please?
Thanks in advance
Luigi

EF Core version: 8.0.0-preview.4.23259.3
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: NET 6.0
Operating system:
IDE: Visual Studio 2022 17.4

This issue is lacking enough information for us to be able to fully understand what is happening. Please attach a small, runnable project or post a small, runnable code listing that reproduces what you are seeing so that we can investigate.

@ajcvickers

Hi @ajcvickers
Please find attached a project for reproducing issue.

ReproducibleNullObject.zip

Note for triage: we don't handle assigning null to the anonymous type after calling DefaultIfEmpty, but it seems like this should work, and it works in LINQ-to-Objects.

@ajcvickers

Hi @ajcvickers
I believe it has same issue with non anonymous type.
Example:

var categories = from c in dbContext.Set<AMOS_ADDRESSCATEGORY>().AsNoTracking()
                         select new Category
                         {
                             Id = c.ADDRESSCATEGORYID,
                             Name = c.DESCRIPTION
                         };

 var addresses = (from address in dbContext.Set<AMOS_ADDRESS>().AsNoTracking()
                                 join c in categories
                                on address.ADDRESSCATEGORYID equals c.Id into aC
                                 from category in aC.DefaultIfEmpty()
                                 select new
                                 {
                                     Id = address.ADDRESSID,
                                     Category = category
                                 }).ToArray();

Hi, Has been solved in version 8 ?
I tested and seems still present..
Thanks in advance

This issue is in the Backlog milestone. This means that it is not fixed in EF Core 8.0. We will re-assess the backlog and consider this item in the upcoming planning. However, keep in mind that there are many other high priority features with which it will be competing for resources. Make sure to vote (👍) for this issue if it is important to you.

Hi, thanks for prompt reply. I believe that this issue should be with high priority because fails on a simple left join operation.
Anyway thanks for suggestion

I have the same exception using a simple group by statement, I think the root cause might be the same. You can run this in roslyn pad to reproduce.

#r "nuget: Microsoft.EntityFrameworkCore.Sqlite,8.0.0"
#r "nuget: Microsoft.EntityFrameworkCore,8.0.0"

using System.ComponentModel.DataAnnotations;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;

await using var ctx = new Context();
await ctx.Database.EnsureDeletedAsync();
await ctx.Database.EnsureCreatedAsync();

ctx.Steps.Add(new Step
{
    Id = 5
});
await ctx.SaveChangesAsync();

await ctx.Steps
    .GroupBy(e => new
    {
        e.Planned
    }).ToListAsync();

public class Context : DbContext
{
    public DbSet<Step> Steps { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder
            .UseSqlite(Environment.ExpandEnvironmentVariables("DataSource=%USERPROFILE%/Desktop/test_db.sqlite"))
            .LogTo(Console.WriteLine, LogLevel.Information)
            .EnableSensitiveDataLogging();
}

public class Step
{
    [Key]
    public int Id { get; set; }
    public DateTime? Planned { get; set; }
}

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Nullable object must have a value thrown for a query with DefaultIfEmpty() #30915

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Nullable object must have a value thrown for a query with DefaultIfEmpty() #30915

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ajcvickers commented on May 17, 2023

Luigi6821 commented on May 17, 2023

ajcvickers commented on May 18, 2023

Luigi6821 commented on May 19, 2023

Luigi6821 commented on Nov 15, 2023

ajcvickers commented on Nov 15, 2023

Luigi6821 commented on Nov 15, 2023

UliPlabst commented on Dec 20, 2023

Luigi6821 commented on Feb 14, 2024

roji commented on Feb 14, 2024

Luigi6821 commented on Feb 15, 2024

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