[v5] OpenApiSchemaService throws InvalidOperationException on nested array references

[DeagleGross]

Description

When generating OpenAPI documents for endpoints whose request bodies have nested types referencing arrays of other types, OpenApiSchemaService throws InvalidOperationException instead of producing the schema.

Reproduction

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddOpenApi();
var app = builder.Build();
app.MapOpenApi();

app.MapPost("/items", (ItemRequest req) => Results.Ok());
app.Run();

public class ItemRequest
{
    public required List<ItemReference> References { get; init; }
}

public class ItemReference
{
    public required string Id { get; init; }
}

Hitting /openapi/v1.json throws:

System.InvalidOperationException: The schema for type 'ItemReference' could not be resolved.
   at Microsoft.AspNetCore.OpenApi.Services.OpenApiSchemaService.GetSchemaForType(Type, ...)

Expected

OpenAPI document should generate with ItemRequest.References as an array of ItemReference references.

Version

.NET 11.0

[DeagleGross]

Triage Summary

Area: area-minimal (issue involves OpenApiSchemaService and OpenAPI document generation for minimal API endpoints — Microsoft.AspNetCore.OpenApi.* runtime APIs)
Type: Bug (a reproducible exception is thrown instead of generating the expected schema)

Potential Duplicates

• None found

Generated by Triage Comment Reviewer for dotnet/aspnetcore for issue #538 · sonnet46 373.4K · ◷