microsoft/OpenAPI.NET

I want to be able to compare two different OpenApiSchema instances for equality. I think it would make sense to implement equality on all object model types so that they implement IEquatable<T> and override object.Equals and GetHashCode methods.

Describe the bug After updating from v3.7.0 to v3.9.0, the nullable property disappears when writing an OpenAPI 3.0 document. Repro steps using Microsoft.OpenApi; var metaSchema = new OpenApiSchema { Type = JsonSchemaType.Object, AdditionalProperties = new OpenApiSchema { Type = JsonSchemaType.Null } }; var baseSchema = new OpenApiSchema { Type = JsonSchemaType.Object, Id = "base", Properties = new Dictionary<string, IOpenApiSchema> { ["id"] = new OpenApiSchema { Type = JsonSchemaType.String } } }; var derivedSchema = new OpenApiSchema { Type = JsonSchemaType.Null, AllOf = new List<IOpenApiSchema> { new OpenApiSchemaReference(baseSchema.Id) }, Properties = new Dictionary<string, IOpenApiSchema> { ["kind"] = new OpenApiSchema { Type = JsonSchemaType.String } } }; var doc = new OpenApiDocument(); doc.Components ??= new OpenApiComponen

In today's implementation (2.11.0, 3.9.0), the deserialization and serialization of JSON Schemas is effectively hard-coded to 2020-12. However, starting with OpenAPI 3.1, people can set the $schema property of any given schema to a different dialect (default being documented here. This entails a couple of things: parsing that keyword first if it exists, or falling back on the document dialect property, or falling back to the default value for the OpenAPI version. if that value is known (like https://spec.openapis.org/oas/3.1/dialect/base using the parsing logic associated with that entry if that value is unknown, we need to load the corresponding schema, and read its schema (recursively) until we find a known value. (note be careful of the security considerations here) Note: ideally we'd make the OpenAPISchema type generic and allow the caller to provide new registrations of schemas uris with the corresponding parsing logic and data type, but that'd introduce major breaking changes,

Describe the bug The OpenApiVisitorBase.PathString is documented as 'Pointer to source of validation error in document', but when used with OpenApiWalker and the built-in validation system, it does not produce correct pointers when the input document is in the v2 format. This is because the walker operates on the shared data model which mirrors the v3 structure - which has already been manipulated by the v2 reader. OpenApi File To Reproduce { "swagger": "2.0", "info": { "title": "Test API", "version": "1.0.0" }, "paths": { "/items": { "get": { "responses": { "200": { "description": "OK", "schema": { "type": "object", "properties": { "id": { "type": "integer" }, "name"