Generated option validators do not check the contents of dictionaries.

[aetos382]

Description

Generated option validators do not check the contents of Dictionary<K, V> types.

Reproduction Steps

using System.ComponentModel.DataAnnotations;

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;

var appBuilder = Host.CreateApplicationBuilder(args);

var configuration = appBuilder.Configuration;

configuration["AppOptions:ComplexOptions:Foo:Value"] = "1";
configuration["AppOptions:ComplexOptions:Bar:Value"] = "200";

var services = appBuilder.Services;

services
    .AddOptionsWithValidateOnStart<AppOptions, AppOptionsValidator>()
    .BindConfiguration("AppOptions");

using var host = appBuilder.Build();

await host.StartAsync().ConfigureAwait(false);

var appOptions = host.Services.GetRequiredService<IOptions<AppOptions>>().Value;

foreach (var (key, value) in appOptions.ComplexOptions)
{
    Console.WriteLine($"{key}={value.Value}");
}

await host.StopAsync().ConfigureAwait(false);

class AppOptions
{
    [Required]
    [ValidateObjectMembers]
    [ValidateEnumeratedItems]
    public Dictionary<string, NestedOptions> ComplexOptions { get; set; } = [];
}

class NestedOptions
{
    [Range(1, 100)]
    public int Value { get; set; }
}

[OptionsValidator]
partial class AppOptionsValidator :
    IValidateOptions<AppOptions>
{
}

Expected behavior

A validation error occurs for AppOptions:ComplexOptions:Bar:Value.

Actual behavior

No validation errors occurred.

Regression?

No response

Known Workarounds

class AppOptions
{
    [Required]
-   [ValidateObjectMembers]
-   [ValidateEnumeratedItems]
    public Dictionary<string, NestedOptions> ComplexOptions { get; set; } = [];

+   [ValidateEnumeratedItems]
+   public ICollection<NestedOptions> ComplexOptionValues => ComplexOptions.Values;
}

Configuration

project:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="9.0.5" />
  </ItemGroup>

</Project>

dotnet --info

PS> dotnet --info

.NET SDK:
Version: 9.0.300
Commit: 15606fe0a8
Workload version: 9.0.300-manifests.87b8cca8
MSBuild version: 17.14.5+edd3bbf37

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.300\

.NET workloads installed:
[android]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 35.0.61/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.android\35.0.61\WorkloadManifest.json
Install Type: Msi

[aspire]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 8.2.2/8.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.aspire\8.2.2\WorkloadManifest.json
Install Type: Msi

[ios]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 18.4.9289/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.ios\18.4.9289\WorkloadManifest.json
Install Type: Msi

[maccatalyst]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 18.4.9289/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.maccatalyst\18.4.9289\WorkloadManifest.json
Install Type: Msi

[maui-windows]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 9.0.51/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.sdk.maui\9.0.51\WorkloadManifest.json
Install Type: Msi

[wasm-tools]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 9.0.5/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.workload.mono.toolchain.current\9.0.5\WorkloadManifest.json
Install Type: Msi

[wasm-tools-net8]
Installation Source: SDK 9.0.300, VS 17.14.36109.1
Manifest Version: 9.0.5/9.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.workload.mono.toolchain.net8\9.0.5\WorkloadManifest.json
Install Type: Msi

Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.5
Architecture: x64
Commit: e36e4d1

.NET SDKs installed:
9.0.300 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.5 [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

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Other information

No response

[aetos382]

If workloads such as the following are not adopted, even DataAnnotations that are not source generators do not seem to validate the contents of the Dictionary.

[ValidateEnumeratedItems]
public ICollection<NestedOptions> ComplexOptionValues => ComplexOptions.Values;

Therefore, other than adding such ugly members, I need to implement custom validation attribute or IValidateOptions<T>.

However, since binding values to a Dictionary is supported out of the box, I would like validation to be supported as well.

[tarekgh]

@aetos382 Why is the specified workaround not sufficient for your needs?

We understand there's a current limitation: Dictionary<TKey, TValue> implements IEnumerable<KeyValuePair<TKey, TValue>>, but KeyValuePair<TKey, TValue> does not support validation attributes. As a result, it does not undergo validation, and we don't have any special handling in place for this scenario.

Similar issue: #94173

[aetos382]

@tarekgh

Why is the specified workaround not sufficient for your needs?

This member is for verification purposes only and does not need to be made public to users.
However, if the visibility of this member is set to anything other than public, error SYSLIB1206 will occur.

[tarekgh]

This member is for verification purposes only and does not need to be made public to users.

Yes, I understand that. I just wanted to clarify—are you saying this workaround isn't acceptable in your specific case, or are you speaking more generally? I'm not denying the current limitation; I was simply asking whether the workaround would be acceptable until a proper fix is implemented in the future.