Make shortening single-field objects configurable because it doesn't work 100% of the time.

Author: Dan Fithian

openapi3-code-generator/src/OpenAPI/Generate/Model.hs

@@ -624,10 +624,13 @@ defineObjectModelForSchema strategy schemaName schema =
           name = haskellifyName convertToCamelCase True schemaName
           required = OAS.schemaObjectRequired schema
           fixedValueStrategy = OAO.settingFixedValueStrategy settings
+          shortenSingleFieldObjects = OAO.settingShortenSingleFieldObjects settings
           (props, propsWithFixedValues) = extractPropertiesWithFixedValues fixedValueStrategy required $ Map.toList $ OAS.schemaObjectProperties schema
           propSuffix = OAO.settingPropertyTypeSuffix settings
           propFields = case props of
-            [(propName, subschema)] -> [(propName, toField convertToCamelCase propName (schemaName <> propSuffix) subschema required)]
+            [(propName, subschema)]
+              | shortenSingleFieldObjects ->
+                  [(propName, toField convertToCamelCase propName (schemaName <> propSuffix) subschema required)]
             _ -> flip fmap props $ \(propName, subschema) ->
               (propName, toField convertToCamelCase propName (schemaName <> uppercaseFirstText propName <> propSuffix) subschema required)
           emptyCtx = pure []

openapi3-code-generator/src/OpenAPI/Generate/OptParse.hs

@@ -110,7 +110,10 @@ data Settings = Settings
     -- in the 'FromJSON' instance.
     -- This setting allows to change this behavior by including all fixed value
     -- fields instead ("include" strategy), i.e. just not trying to do anything smart.
-    settingFixedValueStrategy :: !FixedValueStrategy
+    settingFixedValueStrategy :: !FixedValueStrategy,
+    -- | When encountering an object with a single field, shorten the field of that object to be the
+    -- schema name. Respects property type suffix.
+    settingShortenSingleFieldObjects :: !Bool
   }
   deriving (Show, Eq)
 
@@ -157,6 +160,7 @@ combineToSettings Flags {..} mConf configurationFilePath = do
       settingWhiteListedSchemas = fromMaybe [] $ flagWhiteListedSchemas <|> mc configWhiteListedSchemas
       settingOutputAllSchemas = fromMaybe False $ flagOutputAllSchemas <|> mc configOutputAllSchemas
       settingFixedValueStrategy = fromMaybe FixedValueStrategyExclude $ flagFixedValueStrategy <|> mc configFixedValueStrategy
+      settingShortenSingleFieldObjects = fromMaybe False $ flagShortenSingleFieldObjects <|> mc configShortenSingleFieldObjects
 
   pure Settings {..}
   where

openapi3-code-generator/src/OpenAPI/Generate/OptParse/Configuration.hs

@@ -49,7 +49,8 @@ data Configuration = Configuration
     configOpaqueSchemas :: !(Maybe [Text]),
     configWhiteListedSchemas :: !(Maybe [Text]),
     configOutputAllSchemas :: !(Maybe Bool),
-    configFixedValueStrategy :: !(Maybe FixedValueStrategy)
+    configFixedValueStrategy :: !(Maybe FixedValueStrategy),
+    configShortenSingleFieldObjects :: !(Maybe Bool)
   }
   deriving stock (Show, Eq)
   deriving (FromJSON, ToJSON) via (Autodocodec Configuration)
@@ -91,6 +92,7 @@ instance HasCodec Configuration where
         <*> optionalField "whiteListedSchemas" "A list of schema names (exactly as they are named in the components.schemas section of the corresponding OpenAPI 3 specification) which need to be generated. For all other schemas only a type alias to 'Aeson.Value' is created." .= configWhiteListedSchemas
         <*> optionalField "outputAllSchemas" "Output all component schemas" .= configOutputAllSchemas
         <*> optionalField "fixedValueStrategy" "In OpenAPI 3, fixed values can be defined as an enum with only one allowed value. If such a constant value is encountered as a required property of an object, the generator excludes this property by default ('exclude' strategy) and adds the value in the 'ToJSON' instance and expects the value to be there in the 'FromJSON' instance. This setting allows to change this behavior by including all fixed value fields instead ('include' strategy), i.e. just not trying to do anything smart." .= configFixedValueStrategy
+        <*> optionalField "shortenSingleFieldObjects" "When encountering an object with a single field, shorten the field of that object to be the schema name. Respects property type suffix." .= configShortenSingleFieldObjects
 
 getConfiguration :: Text -> IO (Maybe Configuration)
 getConfiguration path = resolveFile' (T.unpack path) >>= readYamlConfigFile

openapi3-code-generator/src/OpenAPI/Generate/OptParse/Flags.hs

@@ -46,7 +46,8 @@ data Flags = Flags
     flagOpaqueSchemas :: !(Maybe [Text]),
     flagWhiteListedSchemas :: !(Maybe [Text]),
     flagOutputAllSchemas :: !(Maybe Bool),
-    flagFixedValueStrategy :: !(Maybe FixedValueStrategy)
+    flagFixedValueStrategy :: !(Maybe FixedValueStrategy),
+    flagShortenSingleFieldObjects :: !(Maybe Bool)
   }
   deriving (Show, Eq)
 
@@ -87,6 +88,7 @@ parseFlags =
     <*> parseFlagWhiteListedSchemas
     <*> parseFlagOutputAllSchemas
     <*> parseFlagFixedValueStrategy
+    <*> parseFlagShortenSingleFieldObjects
 
 parseFlagConfiguration :: Parser (Maybe Text)
 parseFlagConfiguration =
@@ -382,3 +384,7 @@ parseFlagFixedValueStrategy =
           help "In OpenAPI 3, fixed values can be defined as an enum with only one allowed value. If such a constant value is encountered as a required property of an object, the generator excludes this property by default ('exclude' strategy) and adds the value in the 'ToJSON' instance and expects the value to be there in the 'FromJSON' instance. This setting allows to change this behavior by including all fixed value fields instead ('include' strategy), i.e. just not trying to do anything smart (default: 'exclude').",
           long "fixed-value-strategy"
         ]
+
+parseFlagShortenSingleFieldObjects :: Parser (Maybe Bool)
+parseFlagShortenSingleFieldObjects =
+  booleanFlag "When encountering an object with a single field, shorten the field of that object to be the schema name. Respects property type suffix." "shorten-single-field-objects" Nothing

testing/golden-output/src/OpenAPI/Types/CoverType.hs

@@ -45,50 +45,50 @@ import {-# SOURCE #-} OpenAPI.Types.Value
 -- 
 data CoverType = CoverType {
   -- | cover
-  coverType :: (GHC.Maybe.Maybe CoverTypeVariants)
+  coverTypeCover :: (GHC.Maybe.Maybe CoverTypeCoverVariants)
   } deriving (GHC.Show.Show
   , GHC.Classes.Eq)
 instance Data.Aeson.Types.ToJSON.ToJSON CoverType
-    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (Data.Maybe.maybe GHC.Base.mempty (GHC.Base.pure GHC.Base.. ("cover" Data.Aeson.Types.ToJSON..=)) (coverType obj) : GHC.Base.mempty));
-           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (Data.Maybe.maybe GHC.Base.mempty (GHC.Base.pure GHC.Base.. ("cover" Data.Aeson.Types.ToJSON..=)) (coverType obj) : GHC.Base.mempty)))}
+    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (Data.Maybe.maybe GHC.Base.mempty (GHC.Base.pure GHC.Base.. ("cover" Data.Aeson.Types.ToJSON..=)) (coverTypeCover obj) : GHC.Base.mempty));
+           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (Data.Maybe.maybe GHC.Base.mempty (GHC.Base.pure GHC.Base.. ("cover" Data.Aeson.Types.ToJSON..=)) (coverTypeCover obj) : GHC.Base.mempty)))}
 instance Data.Aeson.Types.FromJSON.FromJSON CoverType
     where {parseJSON = Data.Aeson.Types.FromJSON.withObject "CoverType" (\obj -> GHC.Base.pure CoverType GHC.Base.<*> (obj Data.Aeson.Types.FromJSON..:! "cover"))}
 -- | Create a new 'CoverType' with all required fields.
 mkCoverType :: CoverType
-mkCoverType = CoverType{coverType = GHC.Maybe.Nothing}
+mkCoverType = CoverType{coverTypeCover = GHC.Maybe.Nothing}
 -- | Defines the oneOf schema located at @components.schemas.CoverType.properties.cover.oneOf@ in the specification.
 -- 
 -- 
-data CoverTypeVariants =
-   CoverTypePetByAge PetByAge
-  | CoverTypeMischling Mischling
-  | CoverTypeTest Test
-  | CoverTypeTest2 Test2
-  | CoverTypeTest3 Test3
-  | CoverTypeTest4 Test4
-  | CoverTypeTest5 Test5
-  | CoverTypeTest6 Test6
-  | CoverTypeTest7 Test7
-  | CoverTypeTest8 Test8
-  | CoverTypeTest9 Test9
-  | CoverTypeTest10 Test10
-  | CoverTypeValue Value
+data CoverTypeCoverVariants =
+   CoverTypeCoverPetByAge PetByAge
+  | CoverTypeCoverMischling Mischling
+  | CoverTypeCoverTest Test
+  | CoverTypeCoverTest2 Test2
+  | CoverTypeCoverTest3 Test3
+  | CoverTypeCoverTest4 Test4
+  | CoverTypeCoverTest5 Test5
+  | CoverTypeCoverTest6 Test6
+  | CoverTypeCoverTest7 Test7
+  | CoverTypeCoverTest8 Test8
+  | CoverTypeCoverTest9 Test9
+  | CoverTypeCoverTest10 Test10
+  | CoverTypeCoverValue Value
   deriving (GHC.Show.Show, GHC.Classes.Eq)
-instance Data.Aeson.Types.ToJSON.ToJSON CoverTypeVariants
-    where {toJSON (CoverTypePetByAge a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeMischling a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest2 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest3 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest4 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest5 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest6 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest7 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest8 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest9 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeTest10 a) = Data.Aeson.Types.ToJSON.toJSON a;
-           toJSON (CoverTypeValue a) = Data.Aeson.Types.ToJSON.toJSON a}
-instance Data.Aeson.Types.FromJSON.FromJSON CoverTypeVariants
-    where {parseJSON val = case (CoverTypePetByAge Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeMischling Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest2 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest3 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest4 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest5 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest6 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest7 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest8 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest9 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeTest10 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeValue Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> Data.Aeson.Types.Internal.Error "No variant matched")))))))))))) of
+instance Data.Aeson.Types.ToJSON.ToJSON CoverTypeCoverVariants
+    where {toJSON (CoverTypeCoverPetByAge a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverMischling a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest2 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest3 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest4 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest5 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest6 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest7 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest8 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest9 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverTest10 a) = Data.Aeson.Types.ToJSON.toJSON a;
+           toJSON (CoverTypeCoverValue a) = Data.Aeson.Types.ToJSON.toJSON a}
+instance Data.Aeson.Types.FromJSON.FromJSON CoverTypeCoverVariants
+    where {parseJSON val = case (CoverTypeCoverPetByAge Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverMischling Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest2 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest3 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest4 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest5 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest6 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest7 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest8 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest9 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverTest10 Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> ((CoverTypeCoverValue Data.Functor.<$> Data.Aeson.Types.FromJSON.fromJSON val) GHC.Base.<|> Data.Aeson.Types.Internal.Error "No variant matched")))))))))))) of
                            {Data.Aeson.Types.Internal.Success a -> GHC.Base.pure a;
                             Data.Aeson.Types.Internal.Error a -> Control.Monad.Fail.fail a}}

testing/golden-output/src/OpenAPI/Types/CoverType.hs-boot

@@ -6,8 +6,8 @@ instance Show CoverType
 instance Eq CoverType
 instance Data.Aeson.FromJSON CoverType
 instance Data.Aeson.ToJSON CoverType
-data CoverTypeVariants
-instance Show CoverTypeVariants
-instance Eq CoverTypeVariants
-instance Data.Aeson.FromJSON CoverTypeVariants
-instance Data.Aeson.ToJSON CoverTypeVariants
+data CoverTypeCoverVariants
+instance Show CoverTypeCoverVariants
+instance Eq CoverTypeCoverVariants
+instance Data.Aeson.FromJSON CoverTypeCoverVariants
+instance Data.Aeson.ToJSON CoverTypeCoverVariants

testing/golden-output/src/OpenAPI/Types/Mischling.hs

@@ -160,18 +160,18 @@ mkMischlingAnother_relativeOneOf5 = MischlingAnother_relativeOneOf5{mischlingAno
 -- 
 data MischlingAnother_relativeAnother_cat = MischlingAnother_relativeAnother_cat {
   -- | another_cat
-  mischlingAnother_relativeAnother_cat :: Cat
+  mischlingAnother_relativeAnother_catAnother_cat :: Cat
   } deriving (GHC.Show.Show
   , GHC.Classes.Eq)
 instance Data.Aeson.Types.ToJSON.ToJSON MischlingAnother_relativeAnother_cat
-    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= mischlingAnother_relativeAnother_cat obj] : GHC.Base.mempty));
-           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= mischlingAnother_relativeAnother_cat obj] : GHC.Base.mempty)))}
+    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= mischlingAnother_relativeAnother_catAnother_cat obj] : GHC.Base.mempty));
+           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= mischlingAnother_relativeAnother_catAnother_cat obj] : GHC.Base.mempty)))}
 instance Data.Aeson.Types.FromJSON.FromJSON MischlingAnother_relativeAnother_cat
     where {parseJSON = Data.Aeson.Types.FromJSON.withObject "MischlingAnother_relativeAnother_cat" (\obj -> GHC.Base.pure MischlingAnother_relativeAnother_cat GHC.Base.<*> (obj Data.Aeson.Types.FromJSON..: "another_cat"))}
 -- | Create a new 'MischlingAnother_relativeAnother_cat' with all required fields.
-mkMischlingAnother_relativeAnother_cat :: Cat -- ^ 'mischlingAnother_relativeAnother_cat'
+mkMischlingAnother_relativeAnother_cat :: Cat -- ^ 'mischlingAnother_relativeAnother_catAnother_cat'
   -> MischlingAnother_relativeAnother_cat
-mkMischlingAnother_relativeAnother_cat mischlingAnother_relativeAnother_cat = MischlingAnother_relativeAnother_cat{mischlingAnother_relativeAnother_cat = mischlingAnother_relativeAnother_cat}
+mkMischlingAnother_relativeAnother_cat mischlingAnother_relativeAnother_catAnother_cat = MischlingAnother_relativeAnother_cat{mischlingAnother_relativeAnother_catAnother_cat = mischlingAnother_relativeAnother_catAnother_cat}
 -- | Defines the oneOf schema located at @components.schemas.Mischling.allOf.properties.another_relative.oneOf@ in the specification.
 -- 
 -- 

testing/golden-output/src/OpenAPI/Types/PetByAge.hs

@@ -88,18 +88,18 @@ mkPetByAgeAnother_relativeOneOf5 = PetByAgeAnother_relativeOneOf5{petByAgeAnothe
 -- 
 data PetByAgeAnother_relativeAnother_cat = PetByAgeAnother_relativeAnother_cat {
   -- | another_cat
-  petByAgeAnother_relativeAnother_cat :: Cat
+  petByAgeAnother_relativeAnother_catAnother_cat :: Cat
   } deriving (GHC.Show.Show
   , GHC.Classes.Eq)
 instance Data.Aeson.Types.ToJSON.ToJSON PetByAgeAnother_relativeAnother_cat
-    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= petByAgeAnother_relativeAnother_cat obj] : GHC.Base.mempty));
-           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= petByAgeAnother_relativeAnother_cat obj] : GHC.Base.mempty)))}
+    where {toJSON obj = Data.Aeson.Types.Internal.object (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= petByAgeAnother_relativeAnother_catAnother_cat obj] : GHC.Base.mempty));
+           toEncoding obj = Data.Aeson.Encoding.Internal.pairs (GHC.Base.mconcat (Data.Foldable.concat (["another_cat" Data.Aeson.Types.ToJSON..= petByAgeAnother_relativeAnother_catAnother_cat obj] : GHC.Base.mempty)))}
 instance Data.Aeson.Types.FromJSON.FromJSON PetByAgeAnother_relativeAnother_cat
     where {parseJSON = Data.Aeson.Types.FromJSON.withObject "PetByAgeAnother_relativeAnother_cat" (\obj -> GHC.Base.pure PetByAgeAnother_relativeAnother_cat GHC.Base.<*> (obj Data.Aeson.Types.FromJSON..: "another_cat"))}
 -- | Create a new 'PetByAgeAnother_relativeAnother_cat' with all required fields.
-mkPetByAgeAnother_relativeAnother_cat :: Cat -- ^ 'petByAgeAnother_relativeAnother_cat'
+mkPetByAgeAnother_relativeAnother_cat :: Cat -- ^ 'petByAgeAnother_relativeAnother_catAnother_cat'
   -> PetByAgeAnother_relativeAnother_cat
-mkPetByAgeAnother_relativeAnother_cat petByAgeAnother_relativeAnother_cat = PetByAgeAnother_relativeAnother_cat{petByAgeAnother_relativeAnother_cat = petByAgeAnother_relativeAnother_cat}
+mkPetByAgeAnother_relativeAnother_cat petByAgeAnother_relativeAnother_catAnother_cat = PetByAgeAnother_relativeAnother_cat{petByAgeAnother_relativeAnother_catAnother_cat = petByAgeAnother_relativeAnother_catAnother_cat}
 -- | Defines the oneOf schema located at @components.schemas.PetByAge.properties.another_relative.oneOf@ in the specification.
 -- 
 --