Support Int128 and UInt128 in API binding, ApiExplorer, etc. #43119
Description
.NET 7 introduces the new Int128 and UInt128 structs to represent 128-bit numbers. Attempting to use these new structs in parameters of or responses from minimal APIs or MVC APIs results in broken behavior though, as the type inference logic and serialization doesn't recognize these types.
For example, the following minimal API ends up being described as accepting a string parameter and returning a complex type Int128 with no members (see auto-generated swagger document further below):
app.MapGet("/numbers/{number}", (Int128 number) => new NumbersResult(number, (long)number))
.WithName("Numbers");
record NumbersResult (Int128 Number, long AsLong);{
"openapi": "3.0.1",
"info": {
"title": "WebApplication6",
"version": "1.0"
},
"paths": {
"/numbers/{number}": {
"get": {
"tags": [
"WebApplication6"
],
"operationId": "Numbers",
"parameters": [
{
"name": "number",
"in": "path",
"required": true,
"schema": {
"type": "string"
}
}
],
"responses": {
"200": {
"description": "Success",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/NumbersResult"
}
}
}
}
}
}
}
},
"components": {
"schemas": {
"Int128": {
"type": "object",
"additionalProperties": false
},
"NumbersResult": {
"type": "object",
"properties": {
"number": {
"$ref": "#/components/schemas/Int128"
},
"asLong": {
"type": "integer",
"format": "int64"
}
},
"additionalProperties": false
}
}
}
}