[elm] Add support for oneOf (#4434)

And add additional test for composable types.

bin/openapi3/elm-all.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+./bin/openapi3/elm-petstore.sh
+./bin/openapi3/elm-composition.sh
+

bin/openapi3/elm-composition.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+SCRIPT="$0"
+echo "# START SCRIPT: $SCRIPT"
+
+while [ -h "$SCRIPT" ] ; do
+  ls=`ls -ld "$SCRIPT"`
+  link=`expr "$ls" : '.*-> \(.*\)$'`
+  if expr "$link" : '/.*' > /dev/null; then
+    SCRIPT="$link"
+  else
+    SCRIPT=`dirname "$SCRIPT"`/"$link"
+  fi
+done
+
+if [ ! -d "${APP_DIR}" ]; then
+  APP_DIR=`dirname "$SCRIPT"`/..
+  APP_DIR=`cd "${APP_DIR}"; pwd`
+fi
+
+executable="./modules/openapi-generator-cli/target/openapi-generator-cli.jar"
+
+if [ ! -f "$executable" ]
+then
+  mvn -B clean package
+fi
+
+# auto format elm code using elm-format
+export ELM_POST_PROCESS_FILE="/usr/bin/env elm-format --elm-version=0.19 --yes"
+
+# if you've executed sbt assembly previously it will use that instead.
+export JAVA_OPTS="${JAVA_OPTS} -Xmx1024M -DloggerPath=conf/log4j.properties"
+ags="generate -i modules/openapi-generator/src/test/resources/3_0/composition.yaml -g elm -t modules/openapi-generator/src/main/resources/elm -o samples/openapi3/client/composition/elm --enable-post-process-file $@"
+
+java $JAVA_OPTS -jar $executable $ags

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java

@@ -373,7 +373,13 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
                         elmImports.add(elmImport);
                     }
                 }
-                if (cm.discriminator != null) {
+                if (cm.oneOf != null) {
+                    for (String variant : cm.oneOf) {
+                        final ElmImport elmImport = createImport(variant);
+                        elmImports.add(elmImport);
+                    }
+                }
+                if (cm.discriminator != null && cm.children != null) {
                     for (CodegenModel child : cm.children) {
                         // add child imports
                         final ElmImport elmImport = createImport(child.classname);

modules/openapi-generator/src/main/resources/elm/model.mustache

@@ -1,6 +1,6 @@
 {{>licenseInfo}}
 
-module Data.{{classname}} exposing ({{#models}}{{#model}}{{classname}}{{#hasChildren}}(..){{/hasChildren}}{{#isEnum}}(..){{/isEnum}}{{^isEnum}}{{#vars}}{{#isEnum}}, {{vendorExtensions.elmCustomType}}(..){{/isEnum}}{{/vars}}{{/isEnum}}, decoder, encode, toString{{/model}}{{/models}})
+module Data.{{classname}} exposing ({{#models}}{{#model}}{{classname}}{{#hasChildren}}(..){{/hasChildren}}{{#isEnum}}(..){{/isEnum}}{{^isEnum}}{{#vars}}{{#isEnum}}, {{vendorExtensions.elmCustomType}}(..){{/isEnum}}{{/vars}}{{/isEnum}}, decoder, encode{{^isEnum}}{{^discriminator}}{{^oneOf}}, encodeWithTag{{/oneOf}}{{/discriminator}}{{/isEnum}}, toString{{/model}}{{/models}})
 
 {{>imports}}import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -14,7 +14,7 @@ import Json.Encode as Encode
 {-| {{{description}}}
 -}
 {{/description}}
-{{#isEnum}}{{>modelTypeCustom}}{{/isEnum}}{{^isEnum}}{{#discriminator}}{{>modelTypeDiscriminator}}{{/discriminator}}{{^discriminator}}{{#isAlias}}{{>modelTypePrimitive}}{{/isAlias}}{{^isAlias}}{{#isArrayModel}}{{>modelTypeArray}}{{/isArrayModel}}{{^isArrayModel}}{{>modelTypeRecord}}{{/isArrayModel}}{{/isAlias}}{{/discriminator}}{{/isEnum}}
+{{#isEnum}}{{>modelTypeCustom}}{{/isEnum}}{{^isEnum}}{{#discriminator}}{{>modelTypeDiscriminator}}{{/discriminator}}{{^discriminator}}{{#oneOf}}{{#-first}}{{>modelTypeDiscriminator}}{{/-first}}{{/oneOf}}{{^oneOf}}{{#isAlias}}{{>modelTypePrimitive}}{{/isAlias}}{{^isAlias}}{{#isArrayModel}}{{>modelTypeArray}}{{/isArrayModel}}{{^isArrayModel}}{{>modelTypeRecord}}{{/isArrayModel}}{{/isAlias}}{{/oneOf}}{{/discriminator}}{{/isEnum}}
 
 {{/model}}
 {{/models}}

modules/openapi-generator/src/main/resources/elm/modelTypeDiscriminator.mustache

@@ -1,11 +1,22 @@
 type {{classname}}
-{{#mappedModels}}
+{{^discriminator}}{{#oneOf}}
+    {{#-first}}={{/-first}}{{^-first}}|{{/-first}} {{{.}}}Type {{{.}}}
+{{/oneOf}}{{/discriminator}}
+{{#discriminator}}{{#mappedModels}}
     {{#-first}}={{/-first}}{{^-first}}|{{/-first}} {{modelName}}Type {{modelName}}
-{{/mappedModels}}
+{{/mappedModels}}{{/discriminator}}
 
 
 decoder : Decoder {{classname}}
 decoder =
+{{^discriminator}}
+    Decode.oneOf
+{{#oneOf}}
+        {{#-first}}[{{/-first}}{{^-first}},{{/-first}} Decode.map {{{.}}}Type {{{.}}}.decoder
+{{/oneOf}}
+        ]
+{{/discriminator}}
+{{#discriminator}}
     Decode.field "{{{discriminator.propertyName}}}" Decode.string
         |> Decode.andThen {{classVarName}}Decoder
 
@@ -19,17 +30,25 @@ decoder =
 
 {{/mappedModels}}
         _ ->
-            Decode.fail <| "Trying to decode {{classname}}, but {{{discriminatorName}}} " ++ tag ++ " is not supported."
+            Decode.fail <| "Trying to decode {{classname}}, but {{{discriminatorName}}} '" ++ tag ++ "' is not supported."
+{{/discriminator}}
 
 
 encode : {{classname}} -> Encode.Value
 encode model =
     case model of
+{{^discriminator}}{{#oneOf}}
+        {{{.}}}Type subModel ->
+            {{{.}}}.encode subModel
+
+{{/oneOf}}{{/discriminator}}
+{{#discriminator}}
 {{#mappedModels}}
         {{modelName}}Type subModel ->
-            {{modelName}}.encode "{{mappingName}}" subModel
+            {{modelName}}.encodeWithTag ("{{discriminatorName}}", "{{mappingName}}") subModel
 
 {{/mappedModels}}
+{{/discriminator}}
 
 
 toString : {{classname}} -> String

modules/openapi-generator/src/main/resources/elm/modelTypeRecord.mustache

@@ -18,7 +18,7 @@ type alias {{classname}} =
 
 toString : {{classname}} -> String
 toString =
-    Encode.encode 0 << encode{{#vendorExtensions.discriminatorName}} ""{{/vendorExtensions.discriminatorName}}
+    Encode.encode 0 << encode
 
 
 {{#vars}}

modules/openapi-generator/src/main/resources/elm/recordEncoder.mustache

@@ -1,7 +1,16 @@
-encode : {{#vendorExtensions.discriminatorName}}String -> {{/vendorExtensions.discriminatorName}}{{classname}} -> Encode.Value
+encode : {{classname}} -> Encode.Value
-encode {{#vendorExtensions.discriminatorName}}tag {{/vendorExtensions.discriminatorName}}model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> {{classname}} -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : {{classname}} -> List (String, Encode.Value)
+encodePairs model =
 {{#allVars}}
     {{#-first}}[{{/-first}}{{^-first}},{{/-first}} {{>recordFieldEncoder}}
-{{/allVars}}{{#vendorExtensions.discriminatorName}}        , ( "{{{vendorExtensions.discriminatorName}}}", Encode.string tag ){{/vendorExtensions.discriminatorName}}
+{{/allVars}}
     ]

modules/openapi-generator/src/test/resources/3_0/composition.yaml

@@ -0,0 +1,121 @@
+openapi: 3.0.0
+info:
+  title: Composition and Inheritence (Polymorphism)
+  version: 1.0.0
+paths:
+  /oneOf:
+    post:
+      summary: One of
+      responses:
+        200:
+          description: Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/OneOf'
+  /oneOfWithDiscriminator:
+    post:
+      summary: One of with discriminator
+      responses:
+        200:
+          description: Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/OneOfWithDiscriminator'
+  /oneOfWithAllOfDiscriminator:
+    post:
+      summary: One of with discriminator from all of
+      responses:
+        200:
+          description: Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/OneOfWithAllOfDiscriminator'
+  /allOf:
+    post:
+      summary: All of
+      responses:
+        200:
+          description: Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/AllOf'
+  /allOfWithDiscriminator:
+    post:
+      summary: All of with discriminator
+      responses:
+        200:
+          description: Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/BaseObject'
+components:
+  schemas:
+    OneOf:
+      oneOf:
+        - $ref: "#/components/schemas/ObjectA"
+        - $ref: "#/components/schemas/ObjectB"
+    OneOfWithDiscriminator:
+      oneOf:
+        - $ref: "#/components/schemas/ObjectA"
+        - $ref: "#/components/schemas/ObjectB"
+      discriminator:
+        propertyName: objectType
+        mapping:
+          a: "#/components/schemas/ObjectA"
+          b: "#/components/schemas/ObjectB"
+    OneOfWithAllOfDiscriminator:
+      oneOf:
+        - $ref: "#/components/schemas/SubObjectA"
+        - $ref: "#/components/schemas/SubObjectB"
+    AllOf:
+      allOf:
+        - $ref: "#/components/schemas/ObjectA"
+        - $ref: "#/components/schemas/ObjectB"
+    BaseObject:
+      required:
+        - objectType
+        - value
+      properties:
+        objectType:
+          type: string
+        value:
+          type: boolean
+      discriminator:
+        propertyName: objectType
+    ObjectA:
+      type: object
+      required:
+        - objectType
+      properties:
+        objectType:
+          type: string
+        valueA:
+          type: string
+    ObjectB:
+      type: object
+      required:
+        - objectType
+      properties:
+        objectType:
+          type: string
+        valueB:
+          type: number
+    SubObjectA:
+      allOf:
+        - $ref: "#/components/schemas/BaseObject"
+        - type: object
+          properties:
+            valueA:
+              type: string
+    SubObjectB:
+      allOf:
+        - $ref: "#/components/schemas/BaseObject"
+        - type: object
+          properties:
+            valueB:
+              type: number

samples/client/petstore/elm-0.18/src/Data/ApiResponse.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.ApiResponse exposing (ApiResponse, decoder, encode, toString)
+module Data.ApiResponse exposing (ApiResponse, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -36,8 +36,17 @@ decoder =
 
 
 encode : ApiResponse -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> ApiResponse -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : ApiResponse -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "code", Maybe.withDefault Encode.null (Maybe.map Encode.int model.code) )
     , ( "type", Maybe.withDefault Encode.null (Maybe.map Encode.string model.type_) )
     , ( "message", Maybe.withDefault Encode.null (Maybe.map Encode.string model.message) )

samples/client/petstore/elm-0.18/src/Data/Category.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Category exposing (Category, decoder, encode, toString)
+module Data.Category exposing (Category, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -34,8 +34,17 @@ decoder =
 
 
 encode : Category -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Category -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Category -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
     ]

samples/client/petstore/elm-0.18/src/Data/Order_.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Order_ exposing (Order_, Status(..), decoder, encode, toString)
+module Data.Order_ exposing (Order_, Status(..), decoder, encode, encodeWithTag, toString)
 
 import DateTime exposing (DateTime)
 import Dict exposing (Dict)
@@ -49,8 +49,17 @@ decoder =
 
 
 encode : Order_ -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Order_ -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Order_ -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "petId", Maybe.withDefault Encode.null (Maybe.map Encode.int model.petId) )
     , ( "quantity", Maybe.withDefault Encode.null (Maybe.map Encode.int model.quantity) )

samples/client/petstore/elm-0.18/src/Data/Pet.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Pet exposing (Pet, Status(..), decoder, encode, toString)
+module Data.Pet exposing (Pet, Status(..), decoder, encode, encodeWithTag, toString)
 
 import Data.Category as Category exposing (Category)
 import Data.Tag as Tag exposing (Tag)
@@ -50,8 +50,17 @@ decoder =
 
 
 encode : Pet -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Pet -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Pet -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "category", Maybe.withDefault Encode.null (Maybe.map Category.encode model.category) )
     , ( "name", Encode.string model.name )

samples/client/petstore/elm-0.18/src/Data/Tag.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Tag exposing (Tag, decoder, encode, toString)
+module Data.Tag exposing (Tag, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -34,8 +34,17 @@ decoder =
 
 
 encode : Tag -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Tag -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Tag -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
     ]

samples/client/petstore/elm-0.18/src/Data/User.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.User exposing (User, decoder, encode, toString)
+module Data.User exposing (User, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -46,8 +46,17 @@ decoder =
 
 
 encode : User -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> User -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : User -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "username", Maybe.withDefault Encode.null (Maybe.map Encode.string model.username) )
     , ( "firstName", Maybe.withDefault Encode.null (Maybe.map Encode.string model.firstName) )

samples/client/petstore/elm/src/Data/ApiResponse.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.ApiResponse exposing (ApiResponse, decoder, encode, toString)
+module Data.ApiResponse exposing (ApiResponse, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -36,8 +36,17 @@ decoder =
 
 
 encode : ApiResponse -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> ApiResponse -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : ApiResponse -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "code", Maybe.withDefault Encode.null (Maybe.map Encode.int model.code) )
     , ( "type", Maybe.withDefault Encode.null (Maybe.map Encode.string model.type_) )
     , ( "message", Maybe.withDefault Encode.null (Maybe.map Encode.string model.message) )

samples/client/petstore/elm/src/Data/Category.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Category exposing (Category, decoder, encode, toString)
+module Data.Category exposing (Category, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -34,8 +34,17 @@ decoder =
 
 
 encode : Category -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Category -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Category -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
     ]

samples/client/petstore/elm/src/Data/Order_.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Order_ exposing (Order_, Status(..), decoder, encode, toString)
+module Data.Order_ exposing (Order_, Status(..), decoder, encode, encodeWithTag, toString)
 
 import DateTime exposing (DateTime)
 import Dict exposing (Dict)
@@ -49,8 +49,17 @@ decoder =
 
 
 encode : Order_ -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Order_ -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Order_ -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "petId", Maybe.withDefault Encode.null (Maybe.map Encode.int model.petId) )
     , ( "quantity", Maybe.withDefault Encode.null (Maybe.map Encode.int model.quantity) )

samples/client/petstore/elm/src/Data/Pet.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Pet exposing (Pet, Status(..), decoder, encode, toString)
+module Data.Pet exposing (Pet, Status(..), decoder, encode, encodeWithTag, toString)
 
 import Data.Category as Category exposing (Category)
 import Data.Tag as Tag exposing (Tag)
@@ -50,8 +50,17 @@ decoder =
 
 
 encode : Pet -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Pet -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Pet -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "category", Maybe.withDefault Encode.null (Maybe.map Category.encode model.category) )
     , ( "name", Encode.string model.name )

samples/client/petstore/elm/src/Data/Tag.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Tag exposing (Tag, decoder, encode, toString)
+module Data.Tag exposing (Tag, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -34,8 +34,17 @@ decoder =
 
 
 encode : Tag -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Tag -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Tag -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
     ]

samples/client/petstore/elm/src/Data/User.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.User exposing (User, decoder, encode, toString)
+module Data.User exposing (User, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -46,8 +46,17 @@ decoder =
 
 
 encode : User -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> User -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : User -> List ( String, Encode.Value )
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "username", Maybe.withDefault Encode.null (Maybe.map Encode.string model.username) )
     , ( "firstName", Maybe.withDefault Encode.null (Maybe.map Encode.string model.firstName) )

samples/openapi3/client/composition/elm/.gitignore

@@ -0,0 +1 @@
+/elm-stuff

samples/openapi3/client/composition/elm/.openapi-generator-ignore

@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md

samples/openapi3/client/composition/elm/.openapi-generator/VERSION

@@ -0,0 +1 @@
+4.2.1-SNAPSHOT

samples/openapi3/client/composition/elm/README.md

@@ -0,0 +1,10 @@
+# Elm API client
+
+No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+## Overview
+This API client was generated by the [OpenAPI Generator](https://openapi-generator.tech) project. By using the [openapi-spec](https://github.com/OAI/OpenAPI-Specification) from a remote server, you can easily generate an API client.
+
+- API version: 1.0.0
+- Package version: 
+- Build package: org.openapitools.codegen.languages.ElmClientCodegen

samples/openapi3/client/composition/elm/elm-compile-test

@@ -0,0 +1,14 @@
+#!/bin/bash -e
+# elm make all elm files under src
+
+for ELM in `find src -name "*.elm"`
+do
+    echo "Compiling $ELM"
+    elm make $ELM --output /dev/null
+    rc=$?
+    if [[ $rc != 0 ]]
+    then
+        echo "ERROR!! FAILED TO COMPILE $ELM"
+        exit $rc;
+    fi
+done

samples/openapi3/client/composition/elm/elm.json

@@ -0,0 +1,33 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.0",
+    "dependencies": {
+        "direct": {
+            "NoRedInk/elm-json-decode-pipeline": "1.0.0",
+            "danyx23/elm-uuid": "2.1.2",
+            "elm/browser": "1.0.1",
+            "elm/core": "1.0.2",
+            "elm/html": "1.0.0",
+            "elm/http": "2.0.0",
+            "elm/json": "1.1.2",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "rtfeldman/elm-iso8601-date-strings": "1.1.3"
+        },
+        "indirect": {
+            "elm/bytes": "1.0.5",
+            "elm/file": "1.0.1",
+            "elm/parser": "1.1.0",
+            "elm/random": "1.0.0",
+            "elm/regex": "1.0.0",
+            "elm/virtual-dom": "1.0.2"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}

samples/openapi3/client/composition/elm/pom.xml

@@ -0,0 +1,43 @@
+<project>
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>org.openapitools</groupId>
+    <artifactId>ElmCompositionTests</artifactId>
+    <packaging>pom</packaging>
+    <version>1.0-SNAPSHOT</version>
+    <name>Elm Composition Client</name>
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>copy-dependencies</goal>
+                        </goals>
+                        <configuration>
+                            <outputDirectory>${project.build.directory}</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>1.2.1</version>
+                <executions>
+                    <execution>
+                        <id>bundle-test</id>
+                        <phase>integration-test</phase>
+                        <goals>
+                            <goal>exec</goal>
+                        </goals>
+                        <configuration>
+                            <executable>./elm-compile-test</executable>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

samples/openapi3/client/composition/elm/src/Byte.elm

@@ -0,0 +1,18 @@
+module Byte exposing (Byte, decoder, encode)
+
+import Json.Decode as Decode exposing (Decoder)
+import Json.Encode as Encode
+
+
+type alias Byte =
+    String
+
+
+decoder : Decoder Byte
+decoder =
+    Decode.string
+
+
+encode : Byte -> Encode.Value
+encode model =
+    Encode.string model

samples/openapi3/client/composition/elm/src/Data/AllOf.elm

@@ -0,0 +1,56 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.AllOf exposing (AllOf, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias AllOf =
+    { objectType : String
+    , valueA : Maybe String
+    , valueB : Maybe Float
+    }
+
+
+decoder : Decoder AllOf
+decoder =
+    Decode.succeed AllOf
+        |> required "objectType" Decode.string
+        |> optional "valueA" (Decode.nullable Decode.string) Nothing
+        |> optional "valueB" (Decode.nullable Decode.float) Nothing
+
+
+encode : AllOf -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> AllOf -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : AllOf -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "objectType", Encode.string model.objectType )
+    , ( "valueA", Maybe.withDefault Encode.null (Maybe.map Encode.string model.valueA) )
+    , ( "valueB", Maybe.withDefault Encode.null (Maybe.map Encode.float model.valueB) )
+    ]
+
+
+toString : AllOf -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/BaseObject.elm

@@ -0,0 +1,59 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.BaseObject exposing (BaseObject(..), decoder, encode, toString)
+
+import Data.SubObjectA as SubObjectA exposing (SubObjectA)
+import Data.SubObjectB as SubObjectB exposing (SubObjectB)
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type BaseObject
+    = SubObjectAType SubObjectA
+    | SubObjectBType SubObjectB
+
+
+decoder : Decoder BaseObject
+decoder =
+    Decode.field "objectType" Decode.string
+        |> Decode.andThen baseObjectDecoder
+
+
+baseObjectDecoder : String -> Decoder BaseObject
+baseObjectDecoder tag =
+    case tag of
+        "SubObjectA" ->
+            Decode.map SubObjectAType SubObjectA.decoder
+
+        "SubObjectB" ->
+            Decode.map SubObjectBType SubObjectB.decoder
+
+        _ ->
+            Decode.fail <| "Trying to decode BaseObject, but objectType '" ++ tag ++ "' is not supported."
+
+
+encode : BaseObject -> Encode.Value
+encode model =
+    case model of
+        SubObjectAType subModel ->
+            SubObjectA.encodeWithTag ( "objectType", "SubObjectA" ) subModel
+
+        SubObjectBType subModel ->
+            SubObjectB.encodeWithTag ( "objectType", "SubObjectB" ) subModel
+
+
+toString : BaseObject -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/ObjectA.elm

@@ -0,0 +1,53 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.ObjectA exposing (ObjectA, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias ObjectA =
+    { objectType : String
+    , valueA : Maybe String
+    }
+
+
+decoder : Decoder ObjectA
+decoder =
+    Decode.succeed ObjectA
+        |> required "objectType" Decode.string
+        |> optional "valueA" (Decode.nullable Decode.string) Nothing
+
+
+encode : ObjectA -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> ObjectA -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : ObjectA -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "objectType", Encode.string model.objectType )
+    , ( "valueA", Maybe.withDefault Encode.null (Maybe.map Encode.string model.valueA) )
+    ]
+
+
+toString : ObjectA -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/ObjectB.elm

@@ -0,0 +1,53 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.ObjectB exposing (ObjectB, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias ObjectB =
+    { objectType : String
+    , valueB : Maybe Float
+    }
+
+
+decoder : Decoder ObjectB
+decoder =
+    Decode.succeed ObjectB
+        |> required "objectType" Decode.string
+        |> optional "valueB" (Decode.nullable Decode.float) Nothing
+
+
+encode : ObjectB -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> ObjectB -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : ObjectB -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "objectType", Encode.string model.objectType )
+    , ( "valueB", Maybe.withDefault Encode.null (Maybe.map Encode.float model.valueB) )
+    ]
+
+
+toString : ObjectB -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/OneOf.elm

@@ -0,0 +1,48 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.OneOf exposing (OneOf, decoder, encode, toString)
+
+import Data.ObjectA as ObjectA exposing (ObjectA)
+import Data.ObjectB as ObjectB exposing (ObjectB)
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type OneOf
+    = ObjectAType ObjectA
+    | ObjectBType ObjectB
+
+
+decoder : Decoder OneOf
+decoder =
+    Decode.oneOf
+        [ Decode.map ObjectAType ObjectA.decoder
+        , Decode.map ObjectBType ObjectB.decoder
+        ]
+
+
+encode : OneOf -> Encode.Value
+encode model =
+    case model of
+        ObjectAType subModel ->
+            ObjectA.encode subModel
+
+        ObjectBType subModel ->
+            ObjectB.encode subModel
+
+
+toString : OneOf -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/OneOfWithAllOfDiscriminator.elm

@@ -0,0 +1,48 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.OneOfWithAllOfDiscriminator exposing (OneOfWithAllOfDiscriminator, decoder, encode, toString)
+
+import Data.SubObjectA as SubObjectA exposing (SubObjectA)
+import Data.SubObjectB as SubObjectB exposing (SubObjectB)
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type OneOfWithAllOfDiscriminator
+    = SubObjectAType SubObjectA
+    | SubObjectBType SubObjectB
+
+
+decoder : Decoder OneOfWithAllOfDiscriminator
+decoder =
+    Decode.oneOf
+        [ Decode.map SubObjectAType SubObjectA.decoder
+        , Decode.map SubObjectBType SubObjectB.decoder
+        ]
+
+
+encode : OneOfWithAllOfDiscriminator -> Encode.Value
+encode model =
+    case model of
+        SubObjectAType subModel ->
+            SubObjectA.encode subModel
+
+        SubObjectBType subModel ->
+            SubObjectB.encode subModel
+
+
+toString : OneOfWithAllOfDiscriminator -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/OneOfWithDiscriminator.elm

@@ -0,0 +1,59 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.OneOfWithDiscriminator exposing (OneOfWithDiscriminator, decoder, encode, toString)
+
+import Data.ObjectA as ObjectA exposing (ObjectA)
+import Data.ObjectB as ObjectB exposing (ObjectB)
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type OneOfWithDiscriminator
+    = ObjectAType ObjectA
+    | ObjectBType ObjectB
+
+
+decoder : Decoder OneOfWithDiscriminator
+decoder =
+    Decode.field "objectType" Decode.string
+        |> Decode.andThen oneOfWithDiscriminatorDecoder
+
+
+oneOfWithDiscriminatorDecoder : String -> Decoder OneOfWithDiscriminator
+oneOfWithDiscriminatorDecoder tag =
+    case tag of
+        "a" ->
+            Decode.map ObjectAType ObjectA.decoder
+
+        "b" ->
+            Decode.map ObjectBType ObjectB.decoder
+
+        _ ->
+            Decode.fail <| "Trying to decode OneOfWithDiscriminator, but objectType '" ++ tag ++ "' is not supported."
+
+
+encode : OneOfWithDiscriminator -> Encode.Value
+encode model =
+    case model of
+        ObjectAType subModel ->
+            ObjectA.encodeWithTag ( "objectType", "a" ) subModel
+
+        ObjectBType subModel ->
+            ObjectB.encodeWithTag ( "objectType", "b" ) subModel
+
+
+toString : OneOfWithDiscriminator -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/SubObjectA.elm

@@ -0,0 +1,53 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.SubObjectA exposing (SubObjectA, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias SubObjectA =
+    { value : Bool
+    , valueA : Maybe String
+    }
+
+
+decoder : Decoder SubObjectA
+decoder =
+    Decode.succeed SubObjectA
+        |> required "value" Decode.bool
+        |> optional "valueA" (Decode.nullable Decode.string) Nothing
+
+
+encode : SubObjectA -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> SubObjectA -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : SubObjectA -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "value", Encode.bool model.value )
+    , ( "valueA", Maybe.withDefault Encode.null (Maybe.map Encode.string model.valueA) )
+    ]
+
+
+toString : SubObjectA -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/SubObjectAAllOf.elm

@@ -0,0 +1,50 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.SubObjectAAllOf exposing (SubObjectAAllOf, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias SubObjectAAllOf =
+    { valueA : Maybe String
+    }
+
+
+decoder : Decoder SubObjectAAllOf
+decoder =
+    Decode.succeed SubObjectAAllOf
+        |> optional "valueA" (Decode.nullable Decode.string) Nothing
+
+
+encode : SubObjectAAllOf -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> SubObjectAAllOf -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : SubObjectAAllOf -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "valueA", Maybe.withDefault Encode.null (Maybe.map Encode.string model.valueA) )
+    ]
+
+
+toString : SubObjectAAllOf -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/SubObjectB.elm

@@ -0,0 +1,53 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.SubObjectB exposing (SubObjectB, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias SubObjectB =
+    { value : Bool
+    , valueB : Maybe Float
+    }
+
+
+decoder : Decoder SubObjectB
+decoder =
+    Decode.succeed SubObjectB
+        |> required "value" Decode.bool
+        |> optional "valueB" (Decode.nullable Decode.float) Nothing
+
+
+encode : SubObjectB -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> SubObjectB -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : SubObjectB -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "value", Encode.bool model.value )
+    , ( "valueB", Maybe.withDefault Encode.null (Maybe.map Encode.float model.valueB) )
+    ]
+
+
+toString : SubObjectB -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/Data/SubObjectBAllOf.elm

@@ -0,0 +1,50 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Data.SubObjectBAllOf exposing (SubObjectBAllOf, decoder, encode, encodeWithTag, toString)
+
+import Dict exposing (Dict)
+import Json.Decode as Decode exposing (Decoder)
+import Json.Decode.Pipeline exposing (optional, required)
+import Json.Encode as Encode
+
+
+type alias SubObjectBAllOf =
+    { valueB : Maybe Float
+    }
+
+
+decoder : Decoder SubObjectBAllOf
+decoder =
+    Decode.succeed SubObjectBAllOf
+        |> optional "valueB" (Decode.nullable Decode.float) Nothing
+
+
+encode : SubObjectBAllOf -> Encode.Value
+encode =
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> SubObjectBAllOf -> Encode.Value
+encodeWithTag ( tagField, tag ) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : SubObjectBAllOf -> List ( String, Encode.Value )
+encodePairs model =
+    [ ( "valueB", Maybe.withDefault Encode.null (Maybe.map Encode.float model.valueB) )
+    ]
+
+
+toString : SubObjectBAllOf -> String
+toString =
+    Encode.encode 0 << encode

samples/openapi3/client/composition/elm/src/DateOnly.elm

@@ -0,0 +1,37 @@
+module DateOnly exposing (DateOnly, decoder, encode, toString)
+
+import Iso8601
+import Json.Decode as Decode exposing (Decoder)
+import Json.Encode as Encode
+import Result
+import Time
+
+
+type alias DateOnly =
+    Time.Posix
+
+
+decoder : Decoder DateOnly
+decoder =
+    Decode.string
+        |> Decode.andThen decodeIsoString
+
+
+encode : DateOnly -> Encode.Value
+encode =
+    Encode.string << toString
+
+
+decodeIsoString : String -> Decoder DateOnly
+decodeIsoString str =
+    case Iso8601.toTime (str ++ "T00:00:00.000Z") of
+        Result.Ok posix ->
+            Decode.succeed posix
+
+        Result.Err _ ->
+            Decode.fail <| "Invalid date: " ++ str
+
+
+toString : DateOnly -> String
+toString =
+    String.left 10 << Iso8601.fromTime

samples/openapi3/client/composition/elm/src/DateTime.elm

@@ -0,0 +1,37 @@
+module DateTime exposing (DateTime, decoder, encode, toString)
+
+import Iso8601
+import Json.Decode as Decode exposing (Decoder)
+import Json.Encode as Encode
+import Result
+import Time
+
+
+type alias DateTime =
+    Time.Posix
+
+
+decoder : Decoder DateTime
+decoder =
+    Decode.string
+        |> Decode.andThen decodeIsoString
+
+
+encode : DateTime -> Encode.Value
+encode =
+    Encode.string << toString
+
+
+decodeIsoString : String -> Decoder DateTime
+decodeIsoString str =
+    case Iso8601.toTime str of
+        Result.Ok posix ->
+            Decode.succeed posix
+
+        Result.Err _ ->
+            Decode.fail <| "Invalid date: " ++ str
+
+
+toString : DateTime -> String
+toString =
+    Iso8601.fromTime

samples/openapi3/client/composition/elm/src/Main.elm

@@ -0,0 +1,61 @@
+module Main exposing (main)
+
+import Browser
+import Html exposing (Html)
+
+
+main : Program () Model Msg
+main =
+    Browser.element
+        { init = init
+        , view = view
+        , update = update
+        , subscriptions = subscriptions
+        }
+
+
+
+-- MODEL
+
+
+type alias Model =
+    { value : Int
+    }
+
+
+init : () -> ( Model, Cmd Msg )
+init _ =
+    ( Model 0, Cmd.none )
+
+
+
+-- UPDATE
+
+
+type Msg
+    = NoOp
+
+
+update : Msg -> Model -> ( Model, Cmd Msg )
+update msg model =
+    case msg of
+        NoOp ->
+            ( model, Cmd.none )
+
+
+
+-- SUBSCRIPTIONS
+
+
+subscriptions : Model -> Sub Msg
+subscriptions _ =
+    Sub.none
+
+
+
+-- VIEW
+
+
+view : Model -> Html Msg
+view _ =
+    Html.text "main"

samples/openapi3/client/composition/elm/src/Request/Default.elm

@@ -0,0 +1,123 @@
+{-
+   Composition and Inheritence (Polymorphism)
+   No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+   The version of the OpenAPI document: 1.0.0
+
+   NOTE: This file is auto generated by the openapi-generator.
+   https://github.com/openapitools/openapi-generator.git
+   Do not edit this file manually.
+-}
+
+
+module Request.Default exposing (allOfPost, allOfWithDiscriminatorPost, oneOfPost, oneOfWithAllOfDiscriminatorPost, oneOfWithDiscriminatorPost)
+
+import Data.AllOf as AllOf exposing (AllOf)
+import Data.BaseObject as BaseObject exposing (BaseObject)
+import Data.OneOf as OneOf exposing (OneOf)
+import Data.OneOfWithAllOfDiscriminator as OneOfWithAllOfDiscriminator exposing (OneOfWithAllOfDiscriminator)
+import Data.OneOfWithDiscriminator as OneOfWithDiscriminator exposing (OneOfWithDiscriminator)
+import Dict
+import Http
+import Json.Decode as Decode
+import Url.Builder as Url
+
+
+basePath : String
+basePath =
+    "http://localhost"
+
+
+allOfPost :
+    { onSend : Result Http.Error AllOf -> msg
+    }
+    -> Cmd msg
+allOfPost params =
+    Http.request
+        { method = "POST"
+        , headers = List.filterMap identity []
+        , url =
+            Url.crossOrigin basePath
+                [ "allOf" ]
+                (List.filterMap identity [])
+        , body = Http.emptyBody
+        , expect = Http.expectJson params.onSend AllOf.decoder
+        , timeout = Just 30000
+        , tracker = Nothing
+        }
+
+
+allOfWithDiscriminatorPost :
+    { onSend : Result Http.Error BaseObject -> msg
+    }
+    -> Cmd msg
+allOfWithDiscriminatorPost params =
+    Http.request
+        { method = "POST"
+        , headers = List.filterMap identity []
+        , url =
+            Url.crossOrigin basePath
+                [ "allOfWithDiscriminator" ]
+                (List.filterMap identity [])
+        , body = Http.emptyBody
+        , expect = Http.expectJson params.onSend BaseObject.decoder
+        , timeout = Just 30000
+        , tracker = Nothing
+        }
+
+
+oneOfPost :
+    { onSend : Result Http.Error OneOf -> msg
+    }
+    -> Cmd msg
+oneOfPost params =
+    Http.request
+        { method = "POST"
+        , headers = List.filterMap identity []
+        , url =
+            Url.crossOrigin basePath
+                [ "oneOf" ]
+                (List.filterMap identity [])
+        , body = Http.emptyBody
+        , expect = Http.expectJson params.onSend OneOf.decoder
+        , timeout = Just 30000
+        , tracker = Nothing
+        }
+
+
+oneOfWithAllOfDiscriminatorPost :
+    { onSend : Result Http.Error OneOfWithAllOfDiscriminator -> msg
+    }
+    -> Cmd msg
+oneOfWithAllOfDiscriminatorPost params =
+    Http.request
+        { method = "POST"
+        , headers = List.filterMap identity []
+        , url =
+            Url.crossOrigin basePath
+                [ "oneOfWithAllOfDiscriminator" ]
+                (List.filterMap identity [])
+        , body = Http.emptyBody
+        , expect = Http.expectJson params.onSend OneOfWithAllOfDiscriminator.decoder
+        , timeout = Just 30000
+        , tracker = Nothing
+        }
+
+
+oneOfWithDiscriminatorPost :
+    { onSend : Result Http.Error OneOfWithDiscriminator -> msg
+    }
+    -> Cmd msg
+oneOfWithDiscriminatorPost params =
+    Http.request
+        { method = "POST"
+        , headers = List.filterMap identity []
+        , url =
+            Url.crossOrigin basePath
+                [ "oneOfWithDiscriminator" ]
+                (List.filterMap identity [])
+        , body = Http.emptyBody
+        , expect = Http.expectJson params.onSend OneOfWithDiscriminator.decoder
+        , timeout = Just 30000
+        , tracker = Nothing
+        }

samples/openapi3/client/petstore/elm/.openapi-generator/VERSION

@@ -1 +1 @@
-4.0.3-SNAPSHOT
+4.2.1-SNAPSHOT

samples/openapi3/client/petstore/elm/src/Data/ApiResponse.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.ApiResponse exposing (ApiResponse, decoder, encode)
+module Data.ApiResponse exposing (ApiResponse, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -37,12 +37,28 @@ decoder =
 
 
 encode : ApiResponse -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> ApiResponse -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : ApiResponse -> List (String, Encode.Value)
+encodePairs model =
     [ ( "code", Maybe.withDefault Encode.null (Maybe.map Encode.int model.code) )
     , ( "type", Maybe.withDefault Encode.null (Maybe.map Encode.string model.type_) )
     , ( "message", Maybe.withDefault Encode.null (Maybe.map Encode.string model.message) )
-
     ]
 
 
+
+toString : ApiResponse -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Data/Category.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Category exposing (Category, decoder, encode)
+module Data.Category exposing (Category, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -35,11 +35,27 @@ decoder =
 
 
 encode : Category -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Category -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Category -> List (String, Encode.Value)
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
-
     ]
 
 
+
+toString : Category -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Data/InlineObject.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.InlineObject exposing (InlineObject, decoder, encode)
+module Data.InlineObject exposing (InlineObject, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -33,11 +33,27 @@ decoder =
 
 
 encode : InlineObject -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> InlineObject -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : InlineObject -> List (String, Encode.Value)
+encodePairs model =
     [ ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
     , ( "status", Maybe.withDefault Encode.null (Maybe.map Encode.string model.status) )
-
     ]
 
 
+
+toString : InlineObject -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Data/InlineObject1.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.InlineObject1 exposing (InlineObject1, decoder, encode)
+module Data.InlineObject1 exposing (InlineObject1, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -33,11 +33,27 @@ decoder =
 
 
 encode : InlineObject1 -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> InlineObject1 -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : InlineObject1 -> List (String, Encode.Value)
+encodePairs model =
     [ ( "additionalMetadata", Maybe.withDefault Encode.null (Maybe.map Encode.string model.additionalMetadata) )
     , ( "file", Maybe.withDefault Encode.null (Maybe.map Encode.string model.file) )
-
     ]
 
 
+
+toString : InlineObject1 -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Data/Order_.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Order_ exposing (Order_, Status(..), decoder, encode)
+module Data.Order_ exposing (Order_, Status(..), decoder, encode, encodeWithTag, toString)
 
 import DateTime exposing (DateTime)
 import Dict exposing (Dict)
@@ -51,19 +51,34 @@ decoder =
 
 
 encode : Order_ -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Order_ -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Order_ -> List (String, Encode.Value)
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "petId", Maybe.withDefault Encode.null (Maybe.map Encode.int model.petId) )
     , ( "quantity", Maybe.withDefault Encode.null (Maybe.map Encode.int model.quantity) )
     , ( "shipDate", Maybe.withDefault Encode.null (Maybe.map DateTime.encode model.shipDate) )
     , ( "status", Maybe.withDefault Encode.null (Maybe.map encodeStatus model.status) )
     , ( "complete", Maybe.withDefault Encode.null (Maybe.map Encode.bool model.complete) )
-
     ]
 
 
 
+toString : Order_ -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+
 statusDecoder : Decoder Status
 statusDecoder =
     Decode.string
@@ -99,3 +114,4 @@ encodeStatus model =
 
 
 
+

samples/openapi3/client/petstore/elm/src/Data/Pet.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Pet exposing (Pet, Status(..), decoder, encode)
+module Data.Pet exposing (Pet, Status(..), decoder, encode, encodeWithTag, toString)
 
 import Data.Category as Category exposing (Category)
 import Data.Tag as Tag exposing (Tag)
@@ -52,19 +52,34 @@ decoder =
 
 
 encode : Pet -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Pet -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Pet -> List (String, Encode.Value)
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "category", Maybe.withDefault Encode.null (Maybe.map Category.encode model.category) )
     , ( "name", Encode.string model.name )
     , ( "photoUrls", (Encode.list Encode.string) model.photoUrls )
     , ( "tags", Maybe.withDefault Encode.null (Maybe.map (Encode.list Tag.encode) model.tags) )
     , ( "status", Maybe.withDefault Encode.null (Maybe.map encodeStatus model.status) )
-
     ]
 
 
 
+toString : Pet -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+
 statusDecoder : Decoder Status
 statusDecoder =
     Decode.string
@@ -100,3 +115,4 @@ encodeStatus model =
 
 
 
+

samples/openapi3/client/petstore/elm/src/Data/Tag.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.Tag exposing (Tag, decoder, encode)
+module Data.Tag exposing (Tag, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -35,11 +35,27 @@ decoder =
 
 
 encode : Tag -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> Tag -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : Tag -> List (String, Encode.Value)
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "name", Maybe.withDefault Encode.null (Maybe.map Encode.string model.name) )
-
     ]
 
 
+
+toString : Tag -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Data/User.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.User exposing (User, decoder, encode)
+module Data.User exposing (User, decoder, encode, encodeWithTag, toString)
 
 import Dict exposing (Dict)
 import Json.Decode as Decode exposing (Decoder)
@@ -47,8 +47,17 @@ decoder =
 
 
 encode : User -> Encode.Value
-encode model =
+encode =
-    Encode.object
+    Encode.object << encodePairs
+
+
+encodeWithTag : ( String, String ) -> User -> Encode.Value
+encodeWithTag (tagField, tag) model =
+    Encode.object <| encodePairs model ++ [ ( tagField, Encode.string tag ) ]
+
+
+encodePairs : User -> List (String, Encode.Value)
+encodePairs model =
     [ ( "id", Maybe.withDefault Encode.null (Maybe.map Encode.int model.id) )
     , ( "username", Maybe.withDefault Encode.null (Maybe.map Encode.string model.username) )
     , ( "firstName", Maybe.withDefault Encode.null (Maybe.map Encode.string model.firstName) )
@@ -57,7 +66,14 @@ encode model =
     , ( "password", Maybe.withDefault Encode.null (Maybe.map Encode.string model.password) )
     , ( "phone", Maybe.withDefault Encode.null (Maybe.map Encode.string model.phone) )
     , ( "userStatus", Maybe.withDefault Encode.null (Maybe.map Encode.int model.userStatus) )
-
     ]
 
 
+
+toString : User -> String
+toString =
+    Encode.encode 0 << encode
+
+
+
+

samples/openapi3/client/petstore/elm/src/Request/Pet.elm

@@ -25,8 +25,8 @@ type Status
     | StatusPending
     | StatusSold
 
-statusToString : Status -> String
+stringifyStatus : Status -> String
-statusToString value =
+stringifyStatus value =
     case value of
         StatusAvailable ->
             "available"
@@ -58,10 +58,10 @@ addPet :
 addPet params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| Pet.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -83,10 +83,10 @@ deletePet :
 deletePet headers params =
     Http.request
         { method = "DELETE"
-        , headers = List.filterMap identity [Maybe.map (Http.header "api_key" ) headers.apiKey]
+        , headers = List.filterMap identity [Maybe.map (Http.header "api_key" << identity) headers.apiKey]
         , url = Url.crossOrigin basePath
             ["pet", String.fromInt params.petId]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -108,10 +108,10 @@ findPetsByStatus :
 findPetsByStatus params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet", "findByStatus"]
-            (List.filterMap identity [Just (Url.string "status" <| (String.join "," << List.map statusToString) params.status)])
+            (List.filterMap identity [(Just << Url.string "status" << String.join "," << List.map stringifyStatus) params.status])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend (Decode.list Pet.decoder)
         , timeout = Just 30000
@@ -127,16 +127,16 @@ findPetsByTags :
 
 
 
-    , tags : List String    , maxCount : Maybe (Int)
+    , tags : List String
     }
     -> Cmd msg
 findPetsByTags params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet", "findByTags"]
-            (List.filterMap identity [Just (Url.string "tags" <| (String.join ",") params.tags), Maybe.map (Url.string "maxCount" << String.fromInt) params.maxCount])
+            (List.filterMap identity [(Just << Url.string "tags" << String.join "," << List.map identity) params.tags])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend (Decode.list Pet.decoder)
         , timeout = Just 30000
@@ -158,10 +158,10 @@ getPetById :
 getPetById params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet", String.fromInt params.petId]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend Pet.decoder
         , timeout = Just 30000
@@ -181,10 +181,10 @@ updatePet :
 updatePet params =
     Http.request
         { method = "PUT"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| Pet.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -204,10 +204,10 @@ updatePetWithForm :
 updatePetWithForm params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet", String.fromInt params.petId]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -227,10 +227,10 @@ uploadFile :
 uploadFile params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["pet", String.fromInt params.petId, "uploadImage"]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend ApiResponse.decoder
         , timeout = Just 30000

samples/openapi3/client/petstore/elm/src/Request/Store.elm

@@ -40,10 +40,10 @@ deleteOrder :
 deleteOrder params =
     Http.request
         { method = "DELETE"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
-            ["store", "order",   params.orderId]
+            ["store", "order", identity params.orderId]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -65,10 +65,10 @@ getInventory :
 getInventory params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["store", "inventory"]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend (Decode.dict Decode.int)
         , timeout = Just 30000
@@ -90,10 +90,10 @@ getOrderById :
 getOrderById params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["store", "order", String.fromInt params.orderId]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend Order_.decoder
         , timeout = Just 30000
@@ -113,10 +113,10 @@ placeOrder :
 placeOrder params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["store", "order"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| Order_.encode params.body
         , expect = Http.expectJson params.onSend Order_.decoder
         , timeout = Just 30000

samples/openapi3/client/petstore/elm/src/Request/User.elm

@@ -40,10 +40,10 @@ createUser :
 createUser params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["user"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| User.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -63,10 +63,10 @@ createUsersWithArrayInput :
 createUsersWithArrayInput params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["user", "createWithArray"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| User.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -86,10 +86,10 @@ createUsersWithListInput :
 createUsersWithListInput params =
     Http.request
         { method = "POST"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["user", "createWithList"]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| User.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -111,10 +111,10 @@ deleteUser :
 deleteUser params =
     Http.request
         { method = "DELETE"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
-            ["user",   params.username]
+            ["user", identity params.username]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -134,10 +134,10 @@ getUserByName :
 getUserByName params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
-            ["user",   params.username]
+            ["user", identity params.username]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend User.decoder
         , timeout = Just 30000
@@ -157,10 +157,10 @@ loginUser :
 loginUser params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["user", "login"]
-            (List.filterMap identity [Just (Url.string "username"  params.username), Just (Url.string "password"  params.password)])
+            (List.filterMap identity [(Just << Url.string "username" << identity) params.username, (Just << Url.string "password" << identity) params.password])
         , body = Http.emptyBody
         , expect = Http.expectJson params.onSend Decode.string
         , timeout = Just 30000
@@ -180,10 +180,10 @@ logoutUser :
 logoutUser params =
     Http.request
         { method = "GET"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
             ["user", "logout"]
-            []
+            (List.filterMap identity [])
         , body = Http.emptyBody
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000
@@ -205,10 +205,10 @@ updateUser :
 updateUser params =
     Http.request
         { method = "PUT"
-        , headers = []
+        , headers = List.filterMap identity []
         , url = Url.crossOrigin basePath
-            ["user",   params.username]
+            ["user", identity params.username]
-            []
+            (List.filterMap identity [])
         , body = Http.jsonBody <| User.encode params.body
         , expect = Http.expectWhatever params.onSend
         , timeout = Just 30000