ValidatableTypeAttribute Fails to Generate Validation Metadata Across Assemblies

[pwelter34]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When applying the [ValidatableType] attribute to a class located in a different assembly than the one invoking builder.Services.AddValidation(), the validation metadata for that class is not generated into the GeneratedValidatableInfoResolver.

Expected Behavior

All types annotated with [ValidatableType], regardless of the assembly they reside in, should be included in the generated GeneratedValidatableInfoResolver.

Steps To Reproduce

1. Create a class in Assembly A and annotate it with [ValidatableType].
2. In Assembly B, call builder.Services.AddValidation().
3. Observe that the class from Assembly A is not included in the generated resolver.

Exceptions (if any)

No response

.NET Version

10.0.100-rc.1.25451.107

Anything else?

Proposed Solutions

Primary Solution:

Enhance the source generator to scan all referenced assemblies for [ValidatableType] attributes and include them in the generated GeneratedValidatableInfoResolver.

Alternative Solution:

Generate a separate ValidatableInfoResolver per assembly. These resolvers could then be manually registered with ValidationOptions to compose a complete validation metadata set.

[oroztocil]

@pwelter34 Thank you for contacting us.

To validate types declared in a different assembly A, you can create a method in assembly A which takes the IServiceCollection instance as an argument and calls AddValidation on it. Then in the assembly B where you are configuring your application call both the method from A and AddValidation directly. This will set up the generated type resolvers properly so that types from both assemblies will be able to be validated.

In case the assembly A is not based on Microsoft.NET.Sdk.Web or Microsoft.NET.Sdk.Razor (e.g. it is a plain class library) you will need to add a PackageReference to the Microsoft.Extensions.Validation NuGet package to get the source generator working in that project.

[javiercn]

@pwelter34 to add to what @oroztocil mentions, for the time being this is by design. The source generator doesn't traverse referenced assemblies (doesn't do "discovery") as that has a significant cost during compilation time (it forces the SG to scan all types in the app, not just the ones in the current assembly).

The solution is to do what @oroztocil mentions. Add a reference to the package, create a helper method that takes an IServiceCollection and calls AddValidation() on it and then call that method within your program.

/cc: @captainsafia