[Swift4] DefaultValue variable used in mustache template appears to not exist?

Description

It doesn't appear that the defaultValue variable is being generated when generating models with the language swift4.

Swagger-codegen version

2.4.0

Swagger declaration file content or url

definitions: {
  Order: {
    type: "object",
    properties: {
      id: {
        type: "integer",
        format: "int64"
      },
      petId: {
        type: "integer",
        format: "int64"
      },
      quantity: {
        type: "integer",
        format: "int32"
      },
      shipDate: {
        type: "string",
        format: "date-time"
      },
      status: {
        type: "string",
        description: "Order Status",
        enum: [
          "placed",
          "approved",
          "delivered"
        ]
      },
      complete: {
        type: "boolean",
        default: false
      }
    },
    xml: {
      name: "Order"
    }
  },
...

Command line used for generation

java -jar swagger-codegen-cli.jar generate \
-i https://petstore.swagger.io/v2/swagger.json \
-l swift4 -o /Users/.../.../.../.../.../SwaggerDemo -Dmodels

Steps to reproduce

1) Run the above command to produce swift models based off of the https://petstore.swagger.io/v2/swagger.json Open Api Specification. 2) Inspect the Order.swift model 3) The Order.swift model contains a class definition that looks like this:

public struct Order: Codable {

    public enum Status: String, Codable { 
        case placed = "placed"
        case approved = "approved"
        case delivered = "delivered"
    }
    public var _id: Int64?
    public var petId: Int64?
    public var quantity: Int?
    public var shipDate: Date?
    /** Order Status */
    public var status: Status?
    public var complete: Bool?

The complete Boolean property is defined with a default value, but the default value is not set:

      complete: {
        type: "boolean",
        default: false
      }

Related issues/PRs

Suggest a fix/enhancement

When I debug with -DdebugModels

java -DdebugModels -jar swagger-codegen-cli.jar generate \
  -i petstorecomplete.json \
  -l swift4

I see this output for the OrderClass:

{
      "baseName" : "complete",
      "getter" : "getComplete",
      "setter" : "setComplete",
      "datatype" : "Bool",
      "datatypeWithEnum" : "Bool",
      "name" : "complete",
      "defaultValueWithParam" : " = data.complete;",
      "baseType" : "Bool",
      "jsonSchema" : "{\n  \"type\" : \"boolean\",\n  \"default\" : false\n}",
      "exclusiveMinimum" : false,
      "exclusiveMaximum" : false,
      "hasMore" : false,
      "required" : false,
      "secondaryParam" : false,
      "hasMoreNonReadOnly" : false,
      "isPrimitiveType" : true,
      "isContainer" : false,
      "isNotContainer" : true,
      "isString" : false,
      "isNumeric" : false,
      "isInteger" : false,
      "isLong" : false,
      "isNumber" : false,
      "isFloat" : false,
      "isDouble" : false,
      "isByteArray" : false,
      "isBinary" : false,
      "isFile" : false,
      "isBoolean" : true,
      "isDate" : false,
      "isDateTime" : false,
      "isUuid" : false,
      "isListContainer" : false,
      "isMapContainer" : false,
      "isEnum" : false,
      "isReadOnly" : false,
      "vendorExtensions" : {
        "x-swift-optional-scalar" : true
      },
      "hasValidation" : false,
      "isInherited" : false,
      "nameInCamelCase" : "Complete",
      "isXmlAttribute" : false,
      "isXmlWrapped" : false
    } ],

But the defaultValue parameter used in the mustache file doesn't seem to exist at all:

  {{/description}}public var {{name}}: {{{datatype}}}{{^required}}?{{/required}}{{#defaultValue}} = {{{defaultValue}}}{{/defaultValue}}{{#objcCompatible}}{{#vendorExtensions.x-swift-optional-scalar}}

My only guess is that the defaultValue variable is no longer used or it's not being generated for some reason?

Thank you for any insight!

swagger-api / swagger-codegen