Enable nullable

[damianh]

Enable nullable in OAuth2Introspection.

[Copilot]

Pull Request Overview

This PR enables nullable reference types for the OAuth2 introspection library by removing the <Nullable>disable</Nullable> setting and updating code to handle nullable references correctly.

Key changes include:

• Removing nullable disable directives from project files
• Adding null-forgiving operators and nullable annotations throughout the codebase
• Replacing custom JSON serialization with System.Text.Json
• Removing validation logic that checked for null TokenRetriever

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
SimpleJson.cs	Completely removed custom JSON serialization library
PipelineFactory.cs	Added nullable annotations and switched to System.Text.Json
MockHttpRequest.cs	Added null-forgiving operators and nullable property types
IntrospectionEndpointHandler.cs	Added nullable annotations and improved null handling
Introspection.cs	Added null-forgiving operators for test assertions
Configuration.cs	Removed test for null TokenRetriever validation and added nullable annotation
AssemlyInfo.cs	Added new assembly info file with console capture attribute
OAuth2IntrospectionOptions.cs	Made ClientId and ClientSecret nullable, removed TokenRetriever validation
Project files	Removed nullable disable directives

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[Copilot]

Pull Request Overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

introspection/test/AspNetCore.Authentication.OAuth2Introspection.Tests/Util/IntrospectionEndpointHandler.cs:1

• The clientAssertion variable is created before checking if it's needed. This creates an unnecessary object when options.ClientSecret is not null. Consider moving the creation inside the if block or after the time check.

// Copyright (c) Duende Software. All rights reserved.

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