OpenApiFilterService.CreateFilteredDocument fails if the document is missing the "components" field

[kanales]

Describe the bug
Calling OpenApiFilterService.CreateFilteredDocument on a document that does not contain the optional field OpenApiDocument.Components produces a NullReferenceException.

OpenApi File To Reproduce
Not an OpenApi File, but the following is enough to trigger it.

var openApiDoc = new OpenApiDocument
{
    Info = new()
    {
        Title = "Test",
        Version = "1.0.0"
    },
    Paths = new()
    {
        ["/test"] = new OpenApiPathItem()
        {
            Operations = new Dictionary<OperationType, OpenApiOperation>
            {
                [OperationType.Get] = new OpenApiOperation()
            }
        }
    }
};

var requestUrls = new Dictionary<string, List<string>>()
{
    { "/test", ["GET"] }
};
var filterPredicate = OpenApiFilterService.CreatePredicate(null, null, requestUrls, openApiDoc);
var filteredDocument = OpenApiFilterService.CreateFilteredDocument(openApiDoc, filterPredicate); // Error!

Expected behavior
It should not fail, because the Components field is not mandatory. If it's necessary it should throw a more descriptive exception.

Additional context
Add any other context about the problem here.

[kanales]

I have a solution for this, but I don't seem to be able to push my branch. Let me know how I can help.

[andrueastman]

Are you able to fork the repository and create a PR from there?

[kanales]

Yes that worked, thank you!