Add SkipValidationAttribute to Microsoft.Extensions.Validation

[oroztocil]

Adds an experimental attribute [SkipValidation] that can be used to opt out of validation for a specific property, method parameter, or type.

• When applied to a property, the validator skips that property during validation.
• When aplied to a method parameter, the validator skips the parameter during validation.
• When applied to a type, the validator skips all properties and parameters of that type during validation.
• The source generator skips creating validation code for a type/property/parameter that is only present in the compilation as annotated with the attribute. (If there is at least one use that is not skipped from validation, the code is generated.)

Also fixes issue with GeneratorTests that were using VerifyValidatableType - now the tests can actually fail because the call is awaited and the assertion exceptions are not lost. (Tests using VerifyEndpoint were already awaited.)

Fixes #62862

[Copilot]

Pull Request Overview

This pull request adds an experimental [SkipValidation] attribute to Microsoft.Extensions.Validation that allows developers to opt out of validation for specific properties, method parameters, or entire types. This provides fine-grained control over validation behavior while maintaining the default validation functionality.

Key changes:

• Introduces the SkipValidationAttribute that can be applied to classes, properties, or parameters
• Updates the source generator to skip validation code generation for annotated elements
• Fixes test infrastructure to properly await VerifyValidatableType calls to prevent lost assertion exceptions

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
SkipValidationAttribute.cs	New experimental attribute class with proper target specification
ValidationsGenerator.TypesParser.cs	Updates source generator to check for and skip validation-skipped elements
ITypeSymbolExtensions.cs	Helper methods to determine if symbols have skip validation attributes
RuntimeValidatableParameterInfoResolver.cs	Runtime resolver updated to respect skip validation attributes
ValidationsGeneratorTestBase.cs	Test infrastructure fix to properly await validation type verification
Multiple test snapshots	Generated code snapshots showing proper validation skipping behavior

[javiercn]

Looks good so far.

I'll take a more detailed look at the tests tomorrow

[javiercn]

Looks good to me.

Let's have @captainsafia take a look too before we merge.

[captainsafia]

Looks good on overall structure and implementation!

I left some non-blocking feedback inline about test coverage and source location.

[oroztocil]

Looks good on overall structure and implementation!

I left some non-blocking feedback inline about test coverage and source location.

Thanks, I made the suggested changes 👍