fix(rust): simplify new function optional logic (#17865)

* fix(rust): simplify None logic

Used to be a code path (where isFreeFormObject and something else) where we could end up with two `: None` `: None`'s

This does add the None for the !required && !isArray && !isMap && !isNullable case (where nothing would have been printed before.

Above for the type on the individual vars inside the struct definition the logic is simply if not required then it's optional.
If it's optional we want a None when creating a new struct.

* ci: add tests for failure

bin/configs/rust-hyper-empty-object.yaml

@@ -0,0 +1,8 @@
+generatorName: rust
+outputDir: samples/client/others/rust/hyper/emptyObject
+library: hyper
+inputSpec: modules/openapi-generator/src/test/resources/3_0/rust/empty-object.yaml
+templateDir: modules/openapi-generator/src/main/resources/rust
+additionalProperties:
+  supportAsync: "false"
+  packageName: empty-object-hyper

bin/configs/rust-reqwest-empty-object.yaml

@@ -0,0 +1,8 @@
+generatorName: rust
+outputDir: samples/client/others/rust/reqwest/emptyObject
+library: reqwest
+inputSpec: modules/openapi-generator/src/test/resources/3_0/rust/empty-object.yaml
+templateDir: modules/openapi-generator/src/main/resources/rust
+additionalProperties:
+  supportAsync: "false"
+  packageName: empty-object-reqwest

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

@@ -102,7 +102,7 @@ impl {{{classname}}} {
     pub fn new({{#requiredVars}}{{{name}}}: {{#isNullable}}Option<{{/isNullable}}{{#isEnum}}{{#isArray}}{{#uniqueItems}}std::collections::HashSet<{{/uniqueItems}}{{^uniqueItems}}Vec<{{/uniqueItems}}{{/isArray}}{{{enumName}}}{{#isArray}}>{{/isArray}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}}{{#isNullable}}>{{/isNullable}}{{^-last}}, {{/-last}}{{/requiredVars}}) -> {{{classname}}} {
         {{{classname}}} {
             {{#vars}}
-            {{{name}}}{{^required}}{{#isFreeFormObject}}: None{{/isFreeFormObject}}{{#isContainer}}{{#isArray}}: None{{/isArray}}{{#isMap}}: None{{/isMap}}{{^isArray}}{{^isMap}}{{#isNullable}}: None{{/isNullable}}{{/isMap}}{{/isArray}}{{/isContainer}}{{^isContainer}}: None{{/isContainer}}{{/required}}{{#required}}{{#isModel}}: {{^isNullable}}Box::new({{{name}}}){{/isNullable}}{{#isNullable}}if let Some(x) = {{{name}}} {Some(Box::new(x))} else {None}{{/isNullable}}{{/isModel}}{{/required}},
+            {{{name}}}{{^required}}: None{{/required}}{{#required}}{{#isModel}}: {{^isNullable}}Box::new({{{name}}}){{/isNullable}}{{#isNullable}}if let Some(x) = {{{name}}} {Some(Box::new(x))} else {None}{{/isNullable}}{{/isModel}}{{/required}},
             {{/vars}}
         }
     }

modules/openapi-generator/src/test/resources/3_0/rust/empty-object.yaml

@@ -0,0 +1,23 @@
+openapi: 3.0.0
+info:
+  title: EmptyObject
+  description: Ensure rust supports empty objects using serde::Value
+  version: 1.0.0
+paths:
+  /endpoint:
+    get:
+      summary: Get endpoint
+      responses:
+        "200":
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/EmptyObject"
+components:
+  schemas:
+    EmptyObject:
+      type: object
+      properties:
+        emptyObject:
+          type: object

samples/client/others/rust/Cargo.lock

@@ -134,6 +134,34 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e496a50fda8aacccc86d7529e2c1e0892dbd0f898a6b5645b5561b89c3210efa"
 
+[[package]]
+name = "empty-object-hyper"
+version = "1.0.0"
+dependencies = [
+ "base64 0.7.0",
+ "futures",
+ "http",
+ "hyper",
+ "hyper-tls",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "url",
+ "uuid",
+]
+
+[[package]]
+name = "empty-object-reqwest"
+version = "1.0.0"
+dependencies = [
+ "reqwest",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "url",
+ "uuid",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.32"

samples/client/others/rust/hyper/emptyObject/.gitignore

@@ -0,0 +1,3 @@
+/target/
+**/*.rs.bk
+Cargo.lock

samples/client/others/rust/hyper/emptyObject/.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/client/others/rust/hyper/emptyObject/.openapi-generator/FILES

@@ -0,0 +1,15 @@
+.gitignore
+.travis.yml
+Cargo.toml
+README.md
+docs/DefaultApi.md
+docs/EmptyObject.md
+git_push.sh
+src/apis/client.rs
+src/apis/configuration.rs
+src/apis/default_api.rs
+src/apis/mod.rs
+src/apis/request.rs
+src/lib.rs
+src/models/empty_object.rs
+src/models/mod.rs

samples/client/others/rust/hyper/emptyObject/.openapi-generator/VERSION

@@ -0,0 +1 @@
+7.4.0-SNAPSHOT

samples/client/others/rust/hyper/emptyObject/.travis.yml

@@ -0,0 +1 @@
+language: rust

samples/client/others/rust/hyper/emptyObject/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "empty-object-hyper"
+version = "1.0.0"
+authors = ["OpenAPI Generator team and contributors"]
+description = "Ensure rust supports empty objects using serde::Value"
+# Override this license by providing a License Object in the OpenAPI.
+license = "Unlicense"
+edition = "2018"
+
+[dependencies]
+serde = "^1.0"
+serde_derive = "^1.0"
+serde_json = "^1.0"
+url = "^2.2"
+uuid = { version = "^1.0", features = ["serde", "v4"] }
+hyper = { version = "~0.14", features = ["full"] }
+hyper-tls = "~0.5"
+http = "~0.2"
+base64 = "~0.7.0"
+futures = "^0.3"

samples/client/others/rust/hyper/emptyObject/README.md

@@ -0,0 +1,45 @@
+# Rust API client for empty-object-hyper
+
+Ensure rust supports empty objects using serde::Value
+
+
+## Overview
+
+This API client was generated by the [OpenAPI Generator](https://openapi-generator.tech) project.  By using the [openapi-spec](https://openapis.org) from a remote server, you can easily generate an API client.
+
+- API version: 1.0.0
+- Package version: 1.0.0
+- Build package: `org.openapitools.codegen.languages.RustClientCodegen`
+
+## Installation
+
+Put the package under your project folder in a directory named `empty-object-hyper` and add the following to `Cargo.toml` under `[dependencies]`:
+
+```
+empty-object-hyper = { path = "./empty-object-hyper" }
+```
+
+## Documentation for API Endpoints
+
+All URIs are relative to *http://localhost*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+*DefaultApi* | [**endpoint_get**](docs/DefaultApi.md#endpoint_get) | **Get** /endpoint | Get endpoint
+
+
+## Documentation For Models
+
+ - [EmptyObject](docs/EmptyObject.md)
+
+
+To get access to the crate's generated documentation, use:
+
+```
+cargo doc --open
+```
+
+## Author
+
+
+

samples/client/others/rust/hyper/emptyObject/docs/DefaultApi.md

@@ -0,0 +1,34 @@
+# \DefaultApi
+
+All URIs are relative to *http://localhost*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**endpoint_get**](DefaultApi.md#endpoint_get) | **Get** /endpoint | Get endpoint
+
+
+
+## endpoint_get
+
+> crate::models::EmptyObject endpoint_get()
+Get endpoint
+
+### Parameters
+
+This endpoint does not need any parameter.
+
+### Return type
+
+[**crate::models::EmptyObject**](EmptyObject.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+

samples/client/others/rust/hyper/emptyObject/docs/EmptyObject.md

@@ -0,0 +1,11 @@
+# EmptyObject
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**empty_object** | Option<[**serde_json::Value**](.md)> |  | [optional]
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/client/others/rust/hyper/emptyObject/git_push.sh

@@ -0,0 +1,57 @@
+#!/bin/sh
+# ref: https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/
+#
+# Usage example: /bin/sh ./git_push.sh wing328 openapi-petstore-perl "minor update" "gitlab.com"
+
+git_user_id=$1
+git_repo_id=$2
+release_note=$3
+git_host=$4
+
+if [ "$git_host" = "" ]; then
+    git_host="github.com"
+    echo "[INFO] No command line input provided. Set \$git_host to $git_host"
+fi
+
+if [ "$git_user_id" = "" ]; then
+    git_user_id="GIT_USER_ID"
+    echo "[INFO] No command line input provided. Set \$git_user_id to $git_user_id"
+fi
+
+if [ "$git_repo_id" = "" ]; then
+    git_repo_id="GIT_REPO_ID"
+    echo "[INFO] No command line input provided. Set \$git_repo_id to $git_repo_id"
+fi
+
+if [ "$release_note" = "" ]; then
+    release_note="Minor update"
+    echo "[INFO] No command line input provided. Set \$release_note to $release_note"
+fi
+
+# Initialize the local directory as a Git repository
+git init
+
+# Adds the files in the local repository and stages them for commit.
+git add .
+
+# Commits the tracked changes and prepares them to be pushed to a remote repository.
+git commit -m "$release_note"
+
+# Sets the new remote
+git_remote=$(git remote)
+if [ "$git_remote" = "" ]; then # git remote not defined
+
+    if [ "$GIT_TOKEN" = "" ]; then
+        echo "[INFO] \$GIT_TOKEN (environment variable) is not set. Using the git credential in your environment."
+        git remote add origin https://${git_host}/${git_user_id}/${git_repo_id}.git
+    else
+        git remote add origin https://${git_user_id}:"${GIT_TOKEN}"@${git_host}/${git_user_id}/${git_repo_id}.git
+    fi
+
+fi
+
+git pull origin master
+
+# Pushes (Forces) the changes in the local repository up to the remote repository
+echo "Git pushing to https://${git_host}/${git_user_id}/${git_repo_id}.git"
+git push origin master 2>&1 | grep -v 'To https'

samples/client/others/rust/hyper/emptyObject/src/apis/client.rs

@@ -0,0 +1,24 @@
+use std::rc::Rc;
+
+use hyper;
+use super::configuration::Configuration;
+
+pub struct APIClient {
+    default_api: Box<dyn crate::apis::DefaultApi>,
+}
+
+impl APIClient {
+    pub fn new<C: hyper::client::connect::Connect>(configuration: Configuration<C>) -> APIClient
+        where C: Clone + std::marker::Send + Sync + 'static {
+        let rc = Rc::new(configuration);
+
+        APIClient {
+            default_api: Box::new(crate::apis::DefaultApiClient::new(rc.clone())),
+        }
+    }
+
+    pub fn default_api(&self) -> &dyn crate::apis::DefaultApi{
+        self.default_api.as_ref()
+    }
+
+}

samples/client/others/rust/hyper/emptyObject/src/apis/configuration.rs

@@ -0,0 +1,43 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use hyper;
+
+pub struct Configuration<C: hyper::client::connect::Connect>
+    where C: Clone + std::marker::Send + Sync + 'static {
+    pub base_path: String,
+    pub user_agent: Option<String>,
+    pub client: hyper::client::Client<C>,
+    pub basic_auth: Option<BasicAuth>,
+    pub oauth_access_token: Option<String>,
+    pub api_key: Option<ApiKey>,
+    // TODO: take an oauth2 token source, similar to the go one
+}
+
+pub type BasicAuth = (String, Option<String>);
+
+pub struct ApiKey {
+    pub prefix: Option<String>,
+    pub key: String,
+}
+
+impl<C: hyper::client::connect::Connect> Configuration<C>
+    where C: Clone + std::marker::Send + Sync {
+    pub fn new(client: hyper::client::Client<C>) -> Configuration<C> {
+        Configuration {
+            base_path: "http://localhost".to_owned(),
+            user_agent: Some("OpenAPI-Generator/1.0.0/rust".to_owned()),
+            client,
+            basic_auth: None,
+            oauth_access_token: None,
+            api_key: None,
+        }
+    }
+}

samples/client/others/rust/hyper/emptyObject/src/apis/default_api.rs

@@ -0,0 +1,51 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use std::rc::Rc;
+use std::borrow::Borrow;
+use std::pin::Pin;
+#[allow(unused_imports)]
+use std::option::Option;
+
+use hyper;
+use futures::Future;
+
+use super::{Error, configuration};
+use super::request as __internal_request;
+
+pub struct DefaultApiClient<C: hyper::client::connect::Connect>
+    where C: Clone + std::marker::Send + Sync + 'static {
+    configuration: Rc<configuration::Configuration<C>>,
+}
+
+impl<C: hyper::client::connect::Connect> DefaultApiClient<C>
+    where C: Clone + std::marker::Send + Sync {
+    pub fn new(configuration: Rc<configuration::Configuration<C>>) -> DefaultApiClient<C> {
+        DefaultApiClient {
+            configuration,
+        }
+    }
+}
+
+pub trait DefaultApi {
+    fn endpoint_get(&self, ) -> Pin<Box<dyn Future<Output = Result<crate::models::EmptyObject, Error>>>>;
+}
+
+impl<C: hyper::client::connect::Connect>DefaultApi for DefaultApiClient<C>
+    where C: Clone + std::marker::Send + Sync {
+    #[allow(unused_mut)]
+    fn endpoint_get(&self, ) -> Pin<Box<dyn Future<Output = Result<crate::models::EmptyObject, Error>>>> {
+        let mut req = __internal_request::Request::new(hyper::Method::GET, "/endpoint".to_string())
+        ;
+
+        req.execute(self.configuration.borrow())
+    }
+
+}

samples/client/others/rust/hyper/emptyObject/src/apis/mod.rs

@@ -0,0 +1,54 @@
+use http;
+use hyper;
+use serde_json;
+
+#[derive(Debug)]
+pub enum Error {
+    Api(ApiError),
+    Header(hyper::http::header::InvalidHeaderValue),
+    Http(http::Error),
+    Hyper(hyper::Error),
+    Serde(serde_json::Error),
+    UriError(http::uri::InvalidUri),
+}
+
+#[derive(Debug)]
+pub struct ApiError {
+    pub code: hyper::StatusCode,
+    pub body: hyper::body::Body,
+}
+
+impl From<(hyper::StatusCode, hyper::body::Body)> for Error {
+    fn from(e: (hyper::StatusCode, hyper::body::Body)) -> Self {
+        Error::Api(ApiError {
+            code: e.0,
+            body: e.1,
+        })
+    }
+}
+
+impl From<http::Error> for Error {
+    fn from(e: http::Error) -> Self {
+        return Error::Http(e)
+    }
+}
+
+impl From<hyper::Error> for Error {
+    fn from(e: hyper::Error) -> Self {
+        return Error::Hyper(e)
+    }
+}
+
+impl From<serde_json::Error> for Error {
+    fn from(e: serde_json::Error) -> Self {
+        return Error::Serde(e)
+    }
+}
+
+mod request;
+
+mod default_api;
+pub use self::default_api::{ DefaultApi, DefaultApiClient };
+
+pub mod configuration;
+pub mod client;

samples/client/others/rust/hyper/emptyObject/src/apis/request.rs

@@ -0,0 +1,242 @@
+use std::collections::HashMap;
+use std::pin::Pin;
+
+use futures;
+use futures::Future;
+use futures::future::*;
+use hyper;
+use hyper::header::{AUTHORIZATION, CONTENT_LENGTH, CONTENT_TYPE, HeaderValue, USER_AGENT};
+use serde;
+use serde_json;
+
+use super::{configuration, Error};
+
+pub(crate) struct ApiKey {
+    pub in_header: bool,
+    pub in_query: bool,
+    pub param_name: String,
+}
+
+impl ApiKey {
+    fn key(&self, prefix: &Option<String>, key: &str) -> String {
+        match prefix {
+            None => key.to_owned(),
+            Some(ref prefix) => format!("{} {}", prefix, key),
+        }
+    }
+}
+
+#[allow(dead_code)]
+pub(crate) enum Auth {
+    None,
+    ApiKey(ApiKey),
+    Basic,
+    Oauth,
+}
+
+/// If the authorization type is unspecified then it will be automatically detected based
+/// on the configuration. This functionality is useful when the OpenAPI definition does not
+/// include an authorization scheme.
+pub(crate) struct Request {
+    auth: Option<Auth>,
+    method: hyper::Method,
+    path: String,
+    query_params: HashMap<String, String>,
+    no_return_type: bool,
+    path_params: HashMap<String, String>,
+    form_params: HashMap<String, String>,
+    header_params: HashMap<String, String>,
+    // TODO: multiple body params are possible technically, but not supported here.
+    serialized_body: Option<String>,
+}
+
+#[allow(dead_code)]
+impl Request {
+    pub fn new(method: hyper::Method, path: String) -> Self {
+        Request {
+            auth: None,
+            method,
+            path,
+            query_params: HashMap::new(),
+            path_params: HashMap::new(),
+            form_params: HashMap::new(),
+            header_params: HashMap::new(),
+            serialized_body: None,
+            no_return_type: false,
+        }
+    }
+
+    pub fn with_body_param<T: serde::Serialize>(mut self, param: T) -> Self {
+        self.serialized_body = Some(serde_json::to_string(&param).unwrap());
+        self
+    }
+
+    pub fn with_header_param(mut self, basename: String, param: String) -> Self {
+        self.header_params.insert(basename, param);
+        self
+    }
+
+    #[allow(unused)]
+    pub fn with_query_param(mut self, basename: String, param: String) -> Self {
+        self.query_params.insert(basename, param);
+        self
+    }
+
+    #[allow(unused)]
+    pub fn with_path_param(mut self, basename: String, param: String) -> Self {
+        self.path_params.insert(basename, param);
+        self
+    }
+
+    #[allow(unused)]
+    pub fn with_form_param(mut self, basename: String, param: String) -> Self {
+        self.form_params.insert(basename, param);
+        self
+    }
+
+    pub fn returns_nothing(mut self) -> Self {
+        self.no_return_type = true;
+        self
+    }
+
+    pub fn with_auth(mut self, auth: Auth) -> Self {
+        self.auth = Some(auth);
+        self
+    }
+
+    pub fn execute<'a, C, U>(
+        self,
+        conf: &configuration::Configuration<C>,
+    ) -> Pin<Box<dyn Future<Output=Result<U, Error>> + 'a>>
+        where
+            C: hyper::client::connect::Connect + Clone + std::marker::Send + Sync,
+            U: Sized + std::marker::Send + 'a,
+            for<'de> U: serde::Deserialize<'de>,
+    {
+        let mut query_string = ::url::form_urlencoded::Serializer::new("".to_owned());
+
+        let mut path = self.path;
+        for (k, v) in self.path_params {
+            // replace {id} with the value of the id path param
+            path = path.replace(&format!("{{{}}}", k), &v);
+        }
+
+        for (key, val) in self.query_params {
+            query_string.append_pair(&key, &val);
+        }
+
+        let mut uri_str = format!("{}{}", conf.base_path, path);
+
+        let query_string_str = query_string.finish();
+        if !query_string_str.is_empty() {
+            uri_str += "?";
+            uri_str += &query_string_str;
+        }
+        let uri: hyper::Uri = match uri_str.parse() {
+            Err(e) => return Box::pin(futures::future::err(Error::UriError(e))),
+            Ok(u) => u,
+        };
+
+        let mut req_builder = hyper::Request::builder()
+            .uri(uri)
+            .method(self.method);
+
+        // Detect the authorization type if it hasn't been set.
+        let auth = self.auth.unwrap_or_else(||
+            if conf.api_key.is_some() {
+                panic!("Cannot automatically set the API key from the configuration, it must be specified in the OpenAPI definition")
+            } else if conf.oauth_access_token.is_some() {
+                Auth::Oauth
+            } else if conf.basic_auth.is_some() {
+                Auth::Basic
+            } else {
+                Auth::None
+            }
+        );
+        match auth {
+            Auth::ApiKey(apikey) => {
+                if let Some(ref key) = conf.api_key {
+                    let val = apikey.key(&key.prefix, &key.key);
+                    if apikey.in_query {
+                        query_string.append_pair(&apikey.param_name, &val);
+                    }
+                    if apikey.in_header {
+                        req_builder = req_builder.header(&apikey.param_name, val);
+                    }
+                }
+            }
+            Auth::Basic => {
+                if let Some(ref auth_conf) = conf.basic_auth {
+                    let mut text = auth_conf.0.clone();
+                    text.push(':');
+                    if let Some(ref pass) = auth_conf.1 {
+                        text.push_str(&pass[..]);
+                    }
+                    let encoded = base64::encode(&text);
+                    req_builder = req_builder.header(AUTHORIZATION, encoded);
+                }
+            }
+            Auth::Oauth => {
+                if let Some(ref token) = conf.oauth_access_token {
+                    let text = "Bearer ".to_owned() + token;
+                    req_builder = req_builder.header(AUTHORIZATION, text);
+                }
+            }
+            Auth::None => {}
+        }
+
+        if let Some(ref user_agent) = conf.user_agent {
+            req_builder = req_builder.header(USER_AGENT, match HeaderValue::from_str(user_agent) {
+                Ok(header_value) => header_value,
+                Err(e) => return Box::pin(futures::future::err(super::Error::Header(e)))
+            });
+        }
+
+        for (k, v) in self.header_params {
+            req_builder = req_builder.header(&k, v);
+        }
+
+        let req_headers = req_builder.headers_mut().unwrap();
+        let request_result = if self.form_params.len() > 0 {
+            req_headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/x-www-form-urlencoded"));
+            let mut enc = ::url::form_urlencoded::Serializer::new("".to_owned());
+            for (k, v) in self.form_params {
+                enc.append_pair(&k, &v);
+            }
+            req_builder.body(hyper::Body::from(enc.finish()))
+        } else if let Some(body) = self.serialized_body {
+            req_headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
+            req_headers.insert(CONTENT_LENGTH, body.len().into());
+            req_builder.body(hyper::Body::from(body))
+        } else {
+            req_builder.body(hyper::Body::default())
+        };
+        let request = match request_result {
+            Ok(request) => request,
+            Err(e) => return Box::pin(futures::future::err(Error::from(e)))
+        };
+
+        let no_return_type = self.no_return_type;
+        Box::pin(conf.client
+            .request(request)
+            .map_err(|e| Error::from(e))
+            .and_then(move |response| {
+                let status = response.status();
+                if !status.is_success() {
+                    futures::future::err::<U, Error>(Error::from((status, response.into_body()))).boxed()
+                } else if no_return_type {
+                    // This is a hack; if there's no_ret_type, U is (), but serde_json gives an
+                    // error when deserializing "" into (), so deserialize 'null' into it
+                    // instead.
+                    // An alternate option would be to require U: Default, and then return
+                    // U::default() here instead since () implements that, but then we'd
+                    // need to impl default for all models.
+                    futures::future::ok::<U, Error>(serde_json::from_str("null").expect("serde null value")).boxed()
+                } else {
+                    hyper::body::to_bytes(response.into_body())
+                        .map(|bytes| serde_json::from_slice(&bytes.unwrap()))
+                        .map_err(|e| Error::from(e)).boxed()
+                }
+            }))
+    }
+}

samples/client/others/rust/hyper/emptyObject/src/lib.rs

@@ -0,0 +1,11 @@
+#[macro_use]
+extern crate serde_derive;
+
+extern crate serde;
+extern crate serde_json;
+extern crate url;
+extern crate hyper;
+extern crate futures;
+
+pub mod apis;
+pub mod models;

samples/client/others/rust/hyper/emptyObject/src/models/empty_object.rs

@@ -0,0 +1,28 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+
+
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct EmptyObject {
+    #[serde(rename = "emptyObject", skip_serializing_if = "Option::is_none")]
+    pub empty_object: Option<serde_json::Value>,
+}
+
+impl EmptyObject {
+    pub fn new() -> EmptyObject {
+        EmptyObject {
+            empty_object: None,
+        }
+    }
+}
+
+

samples/client/others/rust/hyper/emptyObject/src/models/mod.rs

@@ -0,0 +1,2 @@
+pub mod empty_object;
+pub use self::empty_object::EmptyObject;

samples/client/others/rust/reqwest/emptyObject/.gitignore

@@ -0,0 +1,3 @@
+/target/
+**/*.rs.bk
+Cargo.lock

samples/client/others/rust/reqwest/emptyObject/.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/client/others/rust/reqwest/emptyObject/.openapi-generator/FILES

@@ -0,0 +1,13 @@
+.gitignore
+.travis.yml
+Cargo.toml
+README.md
+docs/DefaultApi.md
+docs/EmptyObject.md
+git_push.sh
+src/apis/configuration.rs
+src/apis/default_api.rs
+src/apis/mod.rs
+src/lib.rs
+src/models/empty_object.rs
+src/models/mod.rs

samples/client/others/rust/reqwest/emptyObject/.openapi-generator/VERSION

@@ -0,0 +1 @@
+7.4.0-SNAPSHOT

samples/client/others/rust/reqwest/emptyObject/.travis.yml

@@ -0,0 +1 @@
+language: rust

samples/client/others/rust/reqwest/emptyObject/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "empty-object-reqwest"
+version = "1.0.0"
+authors = ["OpenAPI Generator team and contributors"]
+description = "Ensure rust supports empty objects using serde::Value"
+# Override this license by providing a License Object in the OpenAPI.
+license = "Unlicense"
+edition = "2018"
+
+[dependencies]
+serde = "^1.0"
+serde_derive = "^1.0"
+serde_json = "^1.0"
+url = "^2.2"
+uuid = { version = "^1.0", features = ["serde", "v4"] }
+[dependencies.reqwest]
+version = "^0.11"
+features = ["json", "blocking", "multipart"]

samples/client/others/rust/reqwest/emptyObject/README.md

@@ -0,0 +1,45 @@
+# Rust API client for empty-object-reqwest
+
+Ensure rust supports empty objects using serde::Value
+
+
+## Overview
+
+This API client was generated by the [OpenAPI Generator](https://openapi-generator.tech) project.  By using the [openapi-spec](https://openapis.org) from a remote server, you can easily generate an API client.
+
+- API version: 1.0.0
+- Package version: 1.0.0
+- Build package: `org.openapitools.codegen.languages.RustClientCodegen`
+
+## Installation
+
+Put the package under your project folder in a directory named `empty-object-reqwest` and add the following to `Cargo.toml` under `[dependencies]`:
+
+```
+empty-object-reqwest = { path = "./empty-object-reqwest" }
+```
+
+## Documentation for API Endpoints
+
+All URIs are relative to *http://localhost*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+*DefaultApi* | [**endpoint_get**](docs/DefaultApi.md#endpoint_get) | **GET** /endpoint | Get endpoint
+
+
+## Documentation For Models
+
+ - [EmptyObject](docs/EmptyObject.md)
+
+
+To get access to the crate's generated documentation, use:
+
+```
+cargo doc --open
+```
+
+## Author
+
+
+

samples/client/others/rust/reqwest/emptyObject/docs/DefaultApi.md

@@ -0,0 +1,34 @@
+# \DefaultApi
+
+All URIs are relative to *http://localhost*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**endpoint_get**](DefaultApi.md#endpoint_get) | **GET** /endpoint | Get endpoint
+
+
+
+## endpoint_get
+
+> crate::models::EmptyObject endpoint_get()
+Get endpoint
+
+### Parameters
+
+This endpoint does not need any parameter.
+
+### Return type
+
+[**crate::models::EmptyObject**](EmptyObject.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+

samples/client/others/rust/reqwest/emptyObject/docs/EmptyObject.md

@@ -0,0 +1,11 @@
+# EmptyObject
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**empty_object** | Option<[**serde_json::Value**](.md)> |  | [optional]
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/client/others/rust/reqwest/emptyObject/git_push.sh

@@ -0,0 +1,57 @@
+#!/bin/sh
+# ref: https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/
+#
+# Usage example: /bin/sh ./git_push.sh wing328 openapi-petstore-perl "minor update" "gitlab.com"
+
+git_user_id=$1
+git_repo_id=$2
+release_note=$3
+git_host=$4
+
+if [ "$git_host" = "" ]; then
+    git_host="github.com"
+    echo "[INFO] No command line input provided. Set \$git_host to $git_host"
+fi
+
+if [ "$git_user_id" = "" ]; then
+    git_user_id="GIT_USER_ID"
+    echo "[INFO] No command line input provided. Set \$git_user_id to $git_user_id"
+fi
+
+if [ "$git_repo_id" = "" ]; then
+    git_repo_id="GIT_REPO_ID"
+    echo "[INFO] No command line input provided. Set \$git_repo_id to $git_repo_id"
+fi
+
+if [ "$release_note" = "" ]; then
+    release_note="Minor update"
+    echo "[INFO] No command line input provided. Set \$release_note to $release_note"
+fi
+
+# Initialize the local directory as a Git repository
+git init
+
+# Adds the files in the local repository and stages them for commit.
+git add .
+
+# Commits the tracked changes and prepares them to be pushed to a remote repository.
+git commit -m "$release_note"
+
+# Sets the new remote
+git_remote=$(git remote)
+if [ "$git_remote" = "" ]; then # git remote not defined
+
+    if [ "$GIT_TOKEN" = "" ]; then
+        echo "[INFO] \$GIT_TOKEN (environment variable) is not set. Using the git credential in your environment."
+        git remote add origin https://${git_host}/${git_user_id}/${git_repo_id}.git
+    else
+        git remote add origin https://${git_user_id}:"${GIT_TOKEN}"@${git_host}/${git_user_id}/${git_repo_id}.git
+    fi
+
+fi
+
+git pull origin master
+
+# Pushes (Forces) the changes in the local repository up to the remote repository
+echo "Git pushing to https://${git_host}/${git_user_id}/${git_repo_id}.git"
+git push origin master 2>&1 | grep -v 'To https'

samples/client/others/rust/reqwest/emptyObject/src/apis/configuration.rs

@@ -0,0 +1,53 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+
+
+#[derive(Debug, Clone)]
+pub struct Configuration {
+    pub base_path: String,
+    pub user_agent: Option<String>,
+    pub client: reqwest::blocking::Client,
+    pub basic_auth: Option<BasicAuth>,
+    pub oauth_access_token: Option<String>,
+    pub bearer_access_token: Option<String>,
+    pub api_key: Option<ApiKey>,
+    // TODO: take an oauth2 token source, similar to the go one
+}
+
+pub type BasicAuth = (String, Option<String>);
+
+#[derive(Debug, Clone)]
+pub struct ApiKey {
+    pub prefix: Option<String>,
+    pub key: String,
+}
+
+
+impl Configuration {
+    pub fn new() -> Configuration {
+        Configuration::default()
+    }
+}
+
+impl Default for Configuration {
+    fn default() -> Self {
+        Configuration {
+            base_path: "http://localhost".to_owned(),
+            user_agent: Some("OpenAPI-Generator/1.0.0/rust".to_owned()),
+            client: reqwest::blocking::Client::new(),
+            basic_auth: None,
+            oauth_access_token: None,
+            bearer_access_token: None,
+            api_key: None,
+
+        }
+    }
+}

samples/client/others/rust/reqwest/emptyObject/src/apis/default_api.rs

@@ -0,0 +1,52 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+
+use reqwest;
+
+use crate::apis::ResponseContent;
+use super::{Error, configuration};
+
+
+/// struct for typed errors of method [`endpoint_get`]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum EndpointGetError {
+    UnknownValue(serde_json::Value),
+}
+
+
+pub fn endpoint_get(configuration: &configuration::Configuration, ) -> Result<crate::models::EmptyObject, Error<EndpointGetError>> {
+    let local_var_configuration = configuration;
+
+    let local_var_client = &local_var_configuration.client;
+
+    let local_var_uri_str = format!("{}/endpoint", local_var_configuration.base_path);
+    let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
+
+    if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
+        local_var_req_builder = local_var_req_builder.header(reqwest::header::USER_AGENT, local_var_user_agent.clone());
+    }
+
+    let local_var_req = local_var_req_builder.build()?;
+    let local_var_resp = local_var_client.execute(local_var_req)?;
+
+    let local_var_status = local_var_resp.status();
+    let local_var_content = local_var_resp.text()?;
+
+    if !local_var_status.is_client_error() && !local_var_status.is_server_error() {
+        serde_json::from_str(&local_var_content).map_err(Error::from)
+    } else {
+        let local_var_entity: Option<EndpointGetError> = serde_json::from_str(&local_var_content).ok();
+        let local_var_error = ResponseContent { status: local_var_status, content: local_var_content, entity: local_var_entity };
+        Err(Error::ResponseError(local_var_error))
+    }
+}
+

samples/client/others/rust/reqwest/emptyObject/src/apis/mod.rs

@@ -0,0 +1,95 @@
+use std::error;
+use std::fmt;
+
+#[derive(Debug, Clone)]
+pub struct ResponseContent<T> {
+    pub status: reqwest::StatusCode,
+    pub content: String,
+    pub entity: Option<T>,
+}
+
+#[derive(Debug)]
+pub enum Error<T> {
+    Reqwest(reqwest::Error),
+    Serde(serde_json::Error),
+    Io(std::io::Error),
+    ResponseError(ResponseContent<T>),
+}
+
+impl <T> fmt::Display for Error<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let (module, e) = match self {
+            Error::Reqwest(e) => ("reqwest", e.to_string()),
+            Error::Serde(e) => ("serde", e.to_string()),
+            Error::Io(e) => ("IO", e.to_string()),
+            Error::ResponseError(e) => ("response", format!("status code {}", e.status)),
+        };
+        write!(f, "error in {}: {}", module, e)
+    }
+}
+
+impl <T: fmt::Debug> error::Error for Error<T> {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        Some(match self {
+            Error::Reqwest(e) => e,
+            Error::Serde(e) => e,
+            Error::Io(e) => e,
+            Error::ResponseError(_) => return None,
+        })
+    }
+}
+
+impl <T> From<reqwest::Error> for Error<T> {
+    fn from(e: reqwest::Error) -> Self {
+        Error::Reqwest(e)
+    }
+}
+
+impl <T> From<serde_json::Error> for Error<T> {
+    fn from(e: serde_json::Error) -> Self {
+        Error::Serde(e)
+    }
+}
+
+impl <T> From<std::io::Error> for Error<T> {
+    fn from(e: std::io::Error) -> Self {
+        Error::Io(e)
+    }
+}
+
+pub fn urlencode<T: AsRef<str>>(s: T) -> String {
+    ::url::form_urlencoded::byte_serialize(s.as_ref().as_bytes()).collect()
+}
+
+pub fn parse_deep_object(prefix: &str, value: &serde_json::Value) -> Vec<(String, String)> {
+    if let serde_json::Value::Object(object) = value {
+        let mut params = vec![];
+
+        for (key, value) in object {
+            match value {
+                serde_json::Value::Object(_) => params.append(&mut parse_deep_object(
+                    &format!("{}[{}]", prefix, key),
+                    value,
+                )),
+                serde_json::Value::Array(array) => {
+                    for (i, value) in array.iter().enumerate() {
+                        params.append(&mut parse_deep_object(
+                            &format!("{}[{}][{}]", prefix, key, i),
+                            value,
+                        ));
+                    }
+                },
+                serde_json::Value::String(s) => params.push((format!("{}[{}]", prefix, key), s.clone())),
+                _ => params.push((format!("{}[{}]", prefix, key), value.to_string())),
+            }
+        }
+
+        return params;
+    }
+
+    unimplemented!("Only objects are supported with style=deepObject")
+}
+
+pub mod default_api;
+
+pub mod configuration;

samples/client/others/rust/reqwest/emptyObject/src/lib.rs

@@ -0,0 +1,10 @@
+#[macro_use]
+extern crate serde_derive;
+
+extern crate serde;
+extern crate serde_json;
+extern crate url;
+extern crate reqwest;
+
+pub mod apis;
+pub mod models;

samples/client/others/rust/reqwest/emptyObject/src/models/empty_object.rs

@@ -0,0 +1,28 @@
+/*
+ * EmptyObject
+ *
+ * Ensure rust supports empty objects using serde::Value
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+
+
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct EmptyObject {
+    #[serde(rename = "emptyObject", skip_serializing_if = "Option::is_none")]
+    pub empty_object: Option<serde_json::Value>,
+}
+
+impl EmptyObject {
+    pub fn new() -> EmptyObject {
+        EmptyObject {
+            empty_object: None,
+        }
+    }
+}
+
+

samples/client/others/rust/reqwest/emptyObject/src/models/mod.rs

@@ -0,0 +1,2 @@
+pub mod empty_object;
+pub use self::empty_object::EmptyObject;