Options Duplicated ListItem

[giammin]

Description

I'm experiencing a strange behavior when using IOption to inject a configuration object deserialized from a config file.

Items on a list are duplicated.

Reproduction Steps

example repo: https://github.com/giammin/OptionDuplicatedListItem

program.cs

using Microsoft.Extensions.Options;

var builder = WebApplication.CreateBuilder(args);

var apiSection = builder.Configuration.GetSection(ApiConfig.SectionName);
builder.Services.AddOptions<ApiConfig>().Bind(apiSection);

var app = builder.Build();

app.MapGet("/config", (IOptionsSnapshot<ApiConfig> config) => TypedResults.Ok(new { config.Value.Pricing }));

app.Run();

public record ApiConfig
{
    public const string SectionName = "ApiConfig";
    public required Pricing Pricing { get; init; } = null!;
}

public record Pricing(Dictionary<ProjectCategory, IEnumerable<ProjectPricingPlan>> Projects);

public record ProjectPricingPlan(string Name, int Limit, decimal Price);

public enum ProjectCategory { CatA, CatB, }

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ApiConfig": {
    "Pricing": {
      "Projects": {
        "CatA": [
          {
            "Name": "Basic",
            "Limit": 100,
            "Price": 8.75
          },
          {
            "Name": "Large",
            "Limit": 500,
            "Price": 19.5
          }
        ],
        "CatB": [
          {
            "Name": "Basic",
            "Limit": 100,
            "Price": 280
          },
          {
            "Name": "Large",
            "Limit": 250,
            "Price": 480
          }
        ]
      }
    }
  }
}

Expected behavior

{
  "pricing": {
    "projects": {
      "CatA": [
        {
          "name": "Basic",
          "limit": 100,
          "price": 8.75
        },
        {
          "name": "Large",
          "limit": 500,
          "price": 19.5
        }
      ],
      "CatB": [
        {
          "name": "Basic",
          "limit": 100,
          "price": 280
        },
        {
          "name": "Large",
          "limit": 250,
          "price": 480
        }
      ]
    }
  }
}

Actual behavior

{
  "pricing": {
    "projects": {
      "CatA": [
        {
          "name": "Basic",
          "limit": 100,
          "price": 8.75
        },
        {
          "name": "Large",
          "limit": 500,
          "price": 19.5
        },
        {
          "name": "Basic",
          "limit": 100,
          "price": 8.75
        },
        {
          "name": "Large",
          "limit": 500,
          "price": 19.5
        }
      ],
      "CatB": [
        {
          "name": "Basic",
          "limit": 100,
          "price": 280
        },
        {
          "name": "Large",
          "limit": 250,
          "price": 480
        },
        {
          "name": "Basic",
          "limit": 100,
          "price": 280
        },
        {
          "name": "Large",
          "limit": 250,
          "price": 480
        }
      ]
    }
  }
}

Regression?

No response

Known Workarounds

No response

Configuration

pwsh  dotnet --info
.NET SDK:
Version: 8.0.403
Commit: c64aa40a71
Workload version: 8.0.400-manifests.58db758f
MSBuild version: 17.11.9+a69bbaaf5

Runtime Environment:
OS Name: Windows
OS Version: 10.0.22631
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\8.0.403\

.NET workloads installed:
Configured to use loose manifests when installing new manifests.
[aspire]
Installation Source: SDK 8.0.400, VS 17.11.35327.3
Manifest Version: 8.2.1/8.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.aspire\8.2.1\WorkloadManifest.json
Install Type: Msi

Host:
Version: 8.0.10
Architecture: x64
Commit: 81cabf2

.NET SDKs installed:
6.0.427 [C:\Program Files\dotnet\sdk]
8.0.110 [C:\Program Files\dotnet\sdk]
8.0.403 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

Other information

it is not related to json deserialization. It happens only when using ioptions

[julealgon]

Does it make a difference if you replace this:

public required Pricing Pricing { get; init; } = null!;

With this:

public Pricing Pricing { get; } = new();

After changing your Pricing model to have a readonly dictionary reference?

public record Pricing
{
    public Dictionary<ProjectCategory, IEnumerable<ProjectPricingPlan>> Projects { get; } = new();
}

Not necessarily a fix, but I suspect it might be initialing/accumulating the values twice because of the writable property plus the constructor parameter.

The above could be a workaround and also help with the investigation.

[giammin]

actually simply initializing the property does the trick

public required Pricing Pricing { get; init; } = new([]);

thanks for the hint!

[julealgon]

actually simply initializing the property does the trick

public required Pricing Pricing { get; init; } = new([]);

thanks for the hint!

@giammin if you want to keep this version, notice you can now also remove the init and the required, for added simplicity and robustness:

public Pricing Pricing { get; } = new([]);