UseDocumentFilter does not put the same properties as the OperationFilter

[jgarciadelanoceda]

In the issue #223 I raised an issue that was that some schemas were missing references when repeated. There was some work of doing DocumentFilter and avoid this problem in the future.
However there are some gaps between the OperationFilter and the DocumentFilter. Example:

#!/usr/bin/env dotnet

#:sdk Microsoft.NET.Sdk.Web
#:package FluentValidation.AspNetCore@*
#:package MicroElements.Swashbuckle.FluentValidation@*
#:package Swashbuckle.AspNetCore@*
#:package Swashbuckle.AspNetCore.SwaggerGen@*
#:property PublishAot=false
#:property ManagePackageVersionsCentrally=false

using System.Reflection;
using FluentValidation;
using FluentValidation.AspNetCore;
using MicroElements.Swashbuckle.FluentValidation.AspNetCore;
using Microsoft.AspNetCore.Mvc;



var builder = WebApplication.CreateBuilder(args);


builder.Services.AddEndpointsApiExplorer().AddControllers()
.ConfigureApiBehaviorOptions(options =>
{
    options.SuppressInferBindingSourcesForParameters = true;
})
.Services
.AddSwaggerGen()
.AddFluentValidationAutoValidation()
.AddFluentValidationClientsideAdapters()
.AddValidatorsFromAssembly(Assembly.GetExecutingAssembly())
.AddFluentValidationRulesToSwagger(configureRegistration: c => c.UseDocumentFilter = true);

var app = builder.Build();
app.UseSwagger();
app.UseSwaggerUI();
app.MapControllers();
app.Run();

[ApiController]
public sealed class ApiController : ControllerBase
{
    [HttpGet("/api/hello")]
    public string Hello(HelloRequest request) => $"Hello {request.Name ?? "world"}!";
	
	[HttpGet("/api/hello2")]
    public string HelloTwo(HelloRequest request) => $"Hello {request.Name ?? "world"}!";
}

public sealed class HelloRequest
{
    [FromQuery]
    public string? Name { get; set; }
    [FromHeader(Name = "X-Correlation-Id")]
    public string? XCorrelationId { get; set; }
}

public sealed class HelloRequestValidator : AbstractValidator<HelloRequest>
{
    public HelloRequestValidator()
    {
        RuleFor(x => x.Name)
        .NotEmpty()
        .MaximumLength(10);

        RuleFor(x => x.XCorrelationId)
        .NotEmpty()
        .MaximumLength(36);
    }
}

See the property XCorrelationId that when is DocumentFlter then the FluentValidationRule isn´t reflected on the OpenApi Schema. When OperationFilter it is being shown

As I think that the DocumentFilter is the solution I file this issue ;)

[avgalex]

Fixed and released in 7.2.1 — https://github.com/micro-elements/MicroElements.Swashbuckle.FluentValidation/releases/tag/v7.2.1 (PR #231). Thanks for the report and the runnable repro, @jgarciadelanoceda — it made the root cause easy to pin down.

Root cause. Both pipelines resolve the schema property key for an alias ("X-Correlation-Id" → XCorrelationId), but the document filter used that resolved key only for required-marking, while the constraint copy still looked the property up by the raw alias — and never found it. The operation filter reassigns the resolved key and additionally falls back to the INameResolver, which the document filter lacked entirely. Both are now in place, so UseDocumentFilter = true reflects NotEmpty/MaximumLength on your X-Correlation-Id header exactly like the operation filter does.

Two more gaps surfaced while mapping the area, both fixed in the same release:

• A dot in a header name ([FromHeader(Name = "X.Trace.Id")] — legal in HTTP) was mistaken for a flattened nested [FromQuery] dot-path (Required property in optional nested type in [FromQuery] parameter is wrongly marked as required #209/Validator for nested type in [FromQuery] parameter is considered even when not used #211): the name was truncated to the last segment and the rules disappeared. Header-bound parameters are now exempt from the dot-path logic in all three parameter pipelines (operation filter, document filter, and the ASP.NET Core FluentValidationOperationTransformer). This one affected the default pipeline as well, not just the document filter.
• The document filter matched parameter names case-sensitively, so DescribeAllParametersInCamelCase made it skip required-marking and the constraint copy. Now case-insensitive, matching the operation filter.

The package is on MyGet now and will be on nuget.org shortly. Please reopen if anything still differs between the two pipelines in your setup.

[jgarciadelanoceda]

Thanks! @avgalex I check that moving to DocumentFilter is right now!