Fix SDK codegen against the latest SDK models (#2459)

package software.amazon.smithy.rustsdk.endpoints

import software.amazon.smithy.codegen.core.CodegenException

import software.amazon.smithy.model.Model

import software.amazon.smithy.model.shapes.ServiceShape

import software.amazon.smithy.model.shapes.ShapeId

import software.amazon.smithy.model.transform.ModelTransformer

import software.amazon.smithy.rulesengine.language.syntax.parameters.Builtins

import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameter

import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameters

import software.amazon.smithy.rulesengine.traits.EndpointRuleSetTrait

import software.amazon.smithy.rust.codegen.client.smithy.ClientCodegenContext

import software.amazon.smithy.rust.codegen.client.smithy.ClientRustModule

import software.amazon.smithy.rust.codegen.client.smithy.customize.ClientCodegenDecorator

import software.amazon.smithy.rust.codegen.core.smithy.customize.AdHocCustomization

import software.amazon.smithy.rust.codegen.core.smithy.customize.adhocCustomization

import software.amazon.smithy.rust.codegen.core.util.extendIf

import software.amazon.smithy.rust.codegen.core.util.letIf

import software.amazon.smithy.rust.codegen.core.util.thenSingletonListOf

import software.amazon.smithy.rustsdk.AwsRuntimeType

import software.amazon.smithy.rustsdk.SdkConfigSection

    override val name: String = "AwsEndpoint"

    override val order: Byte = 100

    override fun transformModel(service: ServiceShape, model: Model): Model {

        val customServices = setOf(

            ShapeId.from("com.amazonaws.s3#AmazonS3"),

            ShapeId.from("com.amazonaws.s3control#AWSS3ControlServiceV20180820"),

            ShapeId.from("com.amazonaws.codecatalyst#CodeCatalyst"),

        )

        if (customServices.contains(service.id)) {

            return model

        }

        // currently, most models incorrectly model region is optional when it is actually required—fix these models:

        return ModelTransformer.create().mapTraits(model) { _, trait ->

            when (trait) {

                is EndpointRuleSetTrait -> {

                    val rules = trait.ruleSet.expectObjectNode()

                    val params = rules.expectObjectMember("parameters")

                    val newParameters = Parameters.builder()

                    params.members.map { (key, value) ->

                        val param = Parameter.fromNode(key, value.expectObjectNode())

                        param.letIf(param.builtIn == Builtins.REGION.builtIn) { parameter ->

                            parameter.toBuilder().required(true).build()

                        }

                    }.forEach(newParameters::addParameter)

                    EndpointRuleSetTrait.builder()

                        .ruleSet(rules.toBuilder().withMember("parameters", newParameters.build().toNode()).build())

                        .build()

                }

                else -> trait

            }

        }

    }

    override fun configCustomizations(

        codegenContext: ClientCodegenContext,

        baseCustomizations: List<ConfigCustomization>,