Minimal API Validation includes validation for service provider service

[martincostello]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Adding Minimal API validation to an existing application running .NET 10, `` types are generated for TimeProvider despite being a service.

This was addressed previously in #61392, so I assume this is an edge case missed previously.

My guess would be because the endpoint points to a method group, rather than being defined inline:

group.MapGet("/time", GetTime);

private static Ok<TimeResponse> GetTime(TimeProvider timeProvider) { ... }

Viewing the source generator output shows the following code in the TryGetValidatableTypeInfo() method:

            if (type == typeof(global::System.TimeZoneInfo))
            {
                validatableInfo = new GeneratedValidatableTypeInfo(
                    type: typeof(global::System.TimeZoneInfo),
                    members: [
                        new GeneratedValidatablePropertyInfo(
                            containingType: typeof(global::System.TimeZoneInfo),
                            propertyType: typeof(global::System.TimeZoneInfo),
                            name: "Local",
                            displayName: "Local"
                        ),
                        new GeneratedValidatablePropertyInfo(
                            containingType: typeof(global::System.TimeZoneInfo),
                            propertyType: typeof(global::System.TimeZoneInfo),
                            name: "Utc",
                            displayName: "Utc"
                        ),
                    ]
                );
                return true;
            }
            if (type == typeof(global::System.TimeProvider))
            {
                validatableInfo = new GeneratedValidatableTypeInfo(
                    type: typeof(global::System.TimeProvider),
                    members: [
                        new GeneratedValidatablePropertyInfo(
                            containingType: typeof(global::System.TimeProvider),
                            propertyType: typeof(global::System.TimeZoneInfo),
                            name: "LocalTimeZone",
                            displayName: "LocalTimeZone"
                        ),
                        new GeneratedValidatablePropertyInfo(
                            containingType: typeof(global::System.TimeProvider),
                            propertyType: typeof(global::System.TimeProvider),
                            name: "System",
                            displayName: "System"
                        ),
                    ]
                );
                return true;
            }

Adding [FromServices] to the endpoint code explicitly removes the types from the generated code.

- private static Ok<TimeResponse> GetTime(TimeProvider timeProvider)
+ private static Ok<TimeResponse> GetTime([FromServices] TimeProvider timeProvider)

Expected Behavior

No GeneratedValidatableTypeInfo is generated for TimeProvider.

Steps To Reproduce

1. Clone martincostello/api@024a90b
2. Run build.ps1 in the root of the repo
3. Run startvs.cmd
4. View the generated code for Microsoft.Extensions.Validation.ValidationsGenerator in Visual Studio.

Exceptions (if any)

None.

.NET Version

10.0.100-rc.1.25414.111

Anything else?

No response

[captainsafia]

@martincostello This behavior is by-design. Absent attributes, we have no way of statically determining at compile-time whether a type is going to be resolved from the DI container or not, so we'll generate the ValidatableTypeInfo for it regardless. At run-time, when we're able to dynamically determine if it is a service type (see here) we skip calling into the validation pipeline.

One option for this specific case is to add TimeProvider to the exempt list here. This works because it's a type from the BCL but we have no way of doing this for arbitrary types in the DI container so the best thing to do to avoid the code generation is to add the SkipValidation or FromServices attribute.

[martincostello]

I did wonder if that was maybe the case, but I only looked at the issue rather than the related PR and the description seemed to suggest it should work without the attribute if it's a service, but yes I realise now that wouldn't work for AoT.