Support multiple discriminator mappings to share one type

Sources/CreateAPI/Generator/Declarations.swift

@@ -246,6 +246,10 @@ struct TypealiasDeclaration: Declaration {
 struct Discriminator {
     let propertyName: String
     let mapping: [String: TypeIdentifier]
+
+    func correspondingMappings(for property: Property) -> Array<(key: String, value: TypeIdentifier)> {
+        mapping.filter { $1 == property.type }.sorted { $0.key < $1.key }
+    }
 }
 
 struct DeclarationMetadata {

Sources/CreateAPI/Generator/Generator+Render.swift

@@ -106,7 +106,7 @@ extension Generator {
                 }
             }
         }
-        
+
         // TODO: Refactor
         var protocols = decl.protocols
         if decl.isForm {

Sources/CreateAPI/Generator/Templates.swift

@@ -311,13 +311,12 @@ final class Templates {
     func initFromDecoderOneOfWithDiscriminator(properties: [Property], discriminator: Discriminator) -> String {
         var statements = ""
         for property in properties {
-            if let correspondingMapping = discriminator.mapping.first(where: { $1 == property.type}) {
+            let correspondingMappings = discriminator.correspondingMappings(for: property)
+            for mapping in correspondingMappings {
                 statements += """
-                case \"\(correspondingMapping.key)\": self = .\(property.name)(try container.decode(\(property.type).self))
+                case \"\(mapping.key)\": self = .\(property.name)(try container.decode(\(property.type).self))
 
                 """
-            } else {
-                continue
             }
         }
 
@@ -344,9 +343,10 @@ final class Templates {
     }    
 
     func encodeOneOf(properties: [Property]) -> String {
-        let statements = properties.map {
+        let statements: [String] = properties.map {
             "case .\($0.name)(let value): try container.encode(value)"
         }
+
         return """
         \(access)func encode(to encoder: Encoder) throws {
             var container = encoder.singleValueContainer()

Tests/CreateAPITests/Expected/discriminator/Sources/Entities.swift

@@ -47,6 +47,7 @@ public struct Container: Codable {
 
             switch (try container.decode(Discriminator.self)).kind {
             case "a": self = .a(try container.decode(A.self))
+            case "d": self = .a(try container.decode(A.self))
             case "b": self = .b(try container.decode(B.self))
             case "c": self = .c(try container.decode(C.self))
 

Tests/CreateAPITests/Specs/discriminator.yaml

@@ -53,3 +53,4 @@ components:
               a: "#/components/schemas/A"
               b: "#/components/schemas/B"
               c: "#/components/schemas/C"
+              d: "#/components/schemas/A"