Detect oneof branches with single fields. When specified, name oneof variants after those fields instead of with numbers. Fix up some utilities for consistency, and add a Field type instead of recomputing property names.

Author: Dan Fithian

openapi3-code-generator/src/OpenAPI/Generate/Internal/Util.hs

@@ -49,7 +49,7 @@ haskellifyText ::
   -- | The identifier to transform
   Text ->
   -- | The resulting identifier
-  String
+  Text
 haskellifyText convertToCamelCase startWithUppercase name =
   let casefn = if startWithUppercase then Char.toUpper else Char.toLower
       replaceChar '.' = '\''
@@ -94,18 +94,19 @@ haskellifyText convertToCamelCase startWithUppercase name =
       replacePlus ('+' : rest) = "Plus" <> replacePlus rest
       replacePlus (x : xs) = x : replacePlus xs
       replacePlus a = a
-   in replaceReservedWord $
-        caseFirstCharCorrectly $
-          generateNameForEmptyIdentifier name $
-            removeIllegalLeadingCharacters $
-              (if convertToCamelCase then toCamelCase else id) $
-                nameWithoutSpecialChars $
-                  replacePlus $
-                    T.unpack name
+   in T.pack $
+        replaceReservedWord $
+          caseFirstCharCorrectly $
+            generateNameForEmptyIdentifier name $
+              removeIllegalLeadingCharacters $
+                (if convertToCamelCase then toCamelCase else id) $
+                  nameWithoutSpecialChars $
+                    replacePlus $
+                      T.unpack name
 
 -- | The same as 'haskellifyText' but transform the result to a 'Name'
 haskellifyName :: Bool -> Bool -> Text -> Name
-haskellifyName convertToCamelCase startWithUppercase name = mkName $ haskellifyText convertToCamelCase startWithUppercase name
+haskellifyName convertToCamelCase startWithUppercase name = mkName . T.unpack $ haskellifyText convertToCamelCase startWithUppercase name
 
 -- | 'OAM.Generator' version of 'haskellifyName'
 haskellifyNameM :: Bool -> Text -> OAM.Generator Name

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

@@ -87,7 +87,7 @@ defineModuleForOperation mainModuleName requestPath method operation = OAM.neste
   convertToCamelCase <- OAM.getSetting OAO.settingConvertToCamelCase
   let operationIdAsText = T.pack $ show operationIdName
       appendToOperationName = ((T.pack $ nameBase operationIdName) <>)
-      moduleName = haskellifyText convertToCamelCase True operationIdAsText
+      moduleName = T.unpack $ haskellifyText convertToCamelCase True operationIdAsText
   OAM.logInfo $ "Generating operation with name '" <> operationIdAsText <> "'"
   (bodySchema, bodyPath) <- getBodySchemaFromOperation operation
   (responseTypeName, responseTransformerExp, responseBodyDefinitions, responseBodyDependencies) <- OAR.getResponseDefinitions operation appendToOperationName

openapi3-code-generator/src/OpenAPI/Generate/Operation.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,
+    -- | Instead of numbering oneof branches as OneOfN, name oneof branches after a single field
+    -- where possible.
+    settingUseSingleFieldNames :: !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
+      settingUseSingleFieldNames = fromMaybe False $ flagUseSingleFieldNames <|> mc configUseSingleFieldNames
 
   pure Settings {..}
   where

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

@@ -49,7 +49,8 @@ data Configuration = Configuration
     configOpaqueSchemas :: !(Maybe [Text]),
     configWhiteListedSchemas :: !(Maybe [Text]),
     configOutputAllSchemas :: !(Maybe Bool),
-    configFixedValueStrategy :: !(Maybe FixedValueStrategy)
+    configFixedValueStrategy :: !(Maybe FixedValueStrategy),
+    configUseSingleFieldNames :: !(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 "useSingleFieldNames" "Instead of numbering oneof branches as OneOfN, name oneof branches after a single field where possible" .= configUseSingleFieldNames
 
 getConfiguration :: Text -> IO (Maybe Configuration)
 getConfiguration path = resolveFile' (T.unpack path) >>= readYamlConfigFile

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

@@ -46,7 +46,8 @@ data Flags = Flags
     flagOpaqueSchemas :: !(Maybe [Text]),
     flagWhiteListedSchemas :: !(Maybe [Text]),
     flagOutputAllSchemas :: !(Maybe Bool),
-    flagFixedValueStrategy :: !(Maybe FixedValueStrategy)
+    flagFixedValueStrategy :: !(Maybe FixedValueStrategy),
+    flagUseSingleFieldNames :: !(Maybe Bool)
   }
   deriving (Show, Eq)
 
@@ -87,6 +88,7 @@ parseFlags =
     <*> parseFlagWhiteListedSchemas
     <*> parseFlagOutputAllSchemas
     <*> parseFlagFixedValueStrategy
+    <*> parseFlagUseSingleFieldNames
 
 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"
         ]
+
+parseFlagUseSingleFieldNames :: Parser (Maybe Bool)
+parseFlagUseSingleFieldNames =
+  booleanFlag "Instead of numbering oneof branches as OneOfN, name oneof branches after a single field where possible" "use-single-field-names" Nothing

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

@@ -114,7 +114,7 @@ errorSuffix = "Error"
 
 -- | Create the name as 'Text' of the response type / data constructor based on a suffix
 createResponseNameAsText :: Bool -> (Text -> Text) -> Text -> Text
-createResponseNameAsText convertToCamelCase appendToOperationName = T.pack . haskellifyText convertToCamelCase True . appendToOperationName
+createResponseNameAsText convertToCamelCase appendToOperationName = haskellifyText convertToCamelCase True . appendToOperationName
 
 -- | Create the name as 'Name' of the response type / data constructor based on a suffix
 createResponseName :: Bool -> (Text -> Text) -> Text -> Name

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

@@ -1,16 +1,18 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 module OpenAPI.Generate.Internal.UtilSpec where
 
 import qualified Data.Char as Char
 import Data.GenValidity.Text ()
+import Data.Text (Text)
 import qualified Data.Text as T
 import Data.Validity.Text ()
 import OpenAPI.Generate.Internal.Util
 import Test.Hspec
 import Test.Validity
 
 -- See https://www.haskell.org/onlinereport/lexemes.html § 2.4
-isValidVarId :: String -> Bool
-isValidVarId "" = False
+isValidVarId :: Text -> Bool
 isValidVarId "case" = False
 isValidVarId "class" = False
 isValidVarId "data" = False
@@ -32,11 +34,14 @@ isValidVarId "of" = False
 isValidVarId "then" = False
 isValidVarId "type" = False
 isValidVarId "where" = False
-isValidVarId (x : xs) = isValidSmall x && isValidSuffix xs
+isValidVarId other = case T.unpack other of
+  [] -> False
+  (x : xs) -> isValidSmall x && isValidSuffix xs
 
-isValidConId :: String -> Bool
-isValidConId "" = False
-isValidConId (x : xs) = isValidLarge x && isValidSuffix xs
+isValidConId :: Text -> Bool
+isValidConId other = case T.unpack other of
+  [] -> False
+  (x : xs) -> isValidLarge x && isValidSuffix xs
 
 isValidSmall :: Char -> Bool
 isValidSmall x = x == '_' || Char.isLower x
@@ -65,4 +70,4 @@ spec = do
   describe "transformToModuleName" $
     it "should be valid module name" $
       forAllValid $
-        isValidConId . T.unpack . transformToModuleName
+        isValidConId . transformToModuleName