From cfef948c11bb5228fc1aa0635254db6674c21f54 Mon Sep 17 00:00:00 2001
From: Linh Tran Tuan <linhduonggnu@gmail.com>
Date: Thu, 7 Nov 2024 19:39:51 +0900
Subject: [PATCH] [Rust-Axum] [Breaking Changes] Prevent Operation response
 with internal Error (#20047)

* [Rust-Axum] Fix: prevent Operation returns Internal Server Error

* Update
---
 .../main/resources/rust-axum/apis.mustache    |  2 +-
 .../output/apikey-auths/src/apis/payments.rs  |  6 +-
 .../output/multipart-v3/src/apis/default.rs   |  6 +-
 .../output/openapi-v3/src/apis/default.rs     | 59 +++++++--------
 .../output/openapi-v3/src/apis/info_repo.rs   |  2 +-
 .../output/openapi-v3/src/apis/repo.rs        |  2 +-
 .../output/ops-v3/src/apis/default.rs         | 74 +++++++++----------
 .../src/apis/another_fake.rs                  |  2 +-
 .../src/apis/fake.rs                          | 26 +++----
 .../src/apis/fake_classname_tags123.rs        |  2 +-
 .../src/apis/pet.rs                           | 16 ++--
 .../src/apis/store.rs                         |  8 +-
 .../src/apis/user.rs                          | 16 ++--
 .../rust-axum/output/petstore/src/apis/pet.rs | 16 ++--
 .../output/petstore/src/apis/store.rs         |  8 +-
 .../output/petstore/src/apis/user.rs          | 16 ++--
 .../ping-bearer-auth/src/apis/default.rs      |  2 +-
 .../rust-axum-header-uuid/src/apis/default.rs |  2 +-
 .../output/rust-axum-test/src/apis/default.rs | 18 ++---
 .../src/apis/default.rs                       |  2 +-
 20 files changed, 141 insertions(+), 144 deletions(-)

diff --git a/modules/openapi-generator/src/main/resources/rust-axum/apis.mustache b/modules/openapi-generator/src/main/resources/rust-axum/apis.mustache
index a44f21379bf9..b897475dea79 100644
--- a/modules/openapi-generator/src/main/resources/rust-axum/apis.mustache
+++ b/modules/openapi-generator/src/main/resources/rust-axum/apis.mustache
@@ -72,7 +72,7 @@ pub trait {{classnamePascalCase}} {
     {{#x-consumes-multipart-related}}
         body: axum::body::Body,
     {{/x-consumes-multipart-related}}
-    ) -> Result<{{{operationId}}}Response, String>;
+    ) -> Result<{{{operationId}}}Response, ()>;
   {{/vendorExtensions}}
   {{^-last}}
 
diff --git a/samples/server/petstore/rust-axum/output/apikey-auths/src/apis/payments.rs b/samples/server/petstore/rust-axum/output/apikey-auths/src/apis/payments.rs
index 4d824e3a9c13..0c694b6d08e8 100644
--- a/samples/server/petstore/rust-axum/output/apikey-auths/src/apis/payments.rs
+++ b/samples/server/petstore/rust-axum/output/apikey-auths/src/apis/payments.rs
@@ -48,7 +48,7 @@ pub trait Payments {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetPaymentMethodByIdPathParams,
-    ) -> Result<GetPaymentMethodByIdResponse, String>;
+    ) -> Result<GetPaymentMethodByIdResponse, ()>;
 
     /// Get payment methods.
     ///
@@ -58,7 +58,7 @@ pub trait Payments {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<GetPaymentMethodsResponse, String>;
+    ) -> Result<GetPaymentMethodsResponse, ()>;
 
     /// Make a payment.
     ///
@@ -70,5 +70,5 @@ pub trait Payments {
         cookies: CookieJar,
         token_in_cookie: Option<String>,
         body: Option<models::Payment>,
-    ) -> Result<PostMakePaymentResponse, String>;
+    ) -> Result<PostMakePaymentResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/multipart-v3/src/apis/default.rs b/samples/server/petstore/rust-axum/output/multipart-v3/src/apis/default.rs
index 27d8cf2ee301..ad21c532ae7e 100644
--- a/samples/server/petstore/rust-axum/output/multipart-v3/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/multipart-v3/src/apis/default.rs
@@ -42,7 +42,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: axum::body::Body,
-    ) -> Result<MultipartRelatedRequestPostResponse, String>;
+    ) -> Result<MultipartRelatedRequestPostResponse, ()>;
 
     /// MultipartRequestPost - POST /multipart_request
     async fn multipart_request_post(
@@ -51,7 +51,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Multipart,
-    ) -> Result<MultipartRequestPostResponse, String>;
+    ) -> Result<MultipartRequestPostResponse, ()>;
 
     /// MultipleIdenticalMimeTypesPost - POST /multiple-identical-mime-types
     async fn multiple_identical_mime_types_post(
@@ -60,5 +60,5 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: axum::body::Body,
-    ) -> Result<MultipleIdenticalMimeTypesPostResponse, String>;
+    ) -> Result<MultipleIdenticalMimeTypesPostResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/default.rs b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/default.rs
index c8908cfc14d8..0e7b62722ca2 100644
--- a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/default.rs
@@ -282,7 +282,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::AnyOfGetQueryParams,
-    ) -> Result<AnyOfGetResponse, String>;
+    ) -> Result<AnyOfGetResponse, ()>;
 
     /// CallbackWithHeaderPost - POST /callback-with-header
     async fn callback_with_header_post(
@@ -291,7 +291,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::CallbackWithHeaderPostQueryParams,
-    ) -> Result<CallbackWithHeaderPostResponse, String>;
+    ) -> Result<CallbackWithHeaderPostResponse, ()>;
 
     /// ComplexQueryParamGet - GET /complex-query-param
     async fn complex_query_param_get(
@@ -300,7 +300,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::ComplexQueryParamGetQueryParams,
-    ) -> Result<ComplexQueryParamGetResponse, String>;
+    ) -> Result<ComplexQueryParamGetResponse, ()>;
 
     /// EnumInPathPathParamGet - GET /enum_in_path/{path_param}
     async fn enum_in_path_path_param_get(
@@ -309,7 +309,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         path_params: models::EnumInPathPathParamGetPathParams,
-    ) -> Result<EnumInPathPathParamGetResponse, String>;
+    ) -> Result<EnumInPathPathParamGetResponse, ()>;
 
     /// Test a Form Post.
     ///
@@ -320,7 +320,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: models::FormTestRequest,
-    ) -> Result<FormTestResponse, String>;
+    ) -> Result<FormTestResponse, ()>;
 
     /// GetWithBooleanParameter - GET /get-with-bool
     async fn get_with_boolean_parameter(
@@ -329,7 +329,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::GetWithBooleanParameterQueryParams,
-    ) -> Result<GetWithBooleanParameterResponse, String>;
+    ) -> Result<GetWithBooleanParameterResponse, ()>;
 
     /// JsonComplexQueryParamGet - GET /json-complex-query-param
     async fn json_complex_query_param_get(
@@ -338,7 +338,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::JsonComplexQueryParamGetQueryParams,
-    ) -> Result<JsonComplexQueryParamGetResponse, String>;
+    ) -> Result<JsonComplexQueryParamGetResponse, ()>;
 
     /// MandatoryRequestHeaderGet - GET /mandatory-request-header
     async fn mandatory_request_header_get(
@@ -347,7 +347,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         header_params: models::MandatoryRequestHeaderGetHeaderParams,
-    ) -> Result<MandatoryRequestHeaderGetResponse, String>;
+    ) -> Result<MandatoryRequestHeaderGetResponse, ()>;
 
     /// MergePatchJsonGet - GET /merge-patch-json
     async fn merge_patch_json_get(
@@ -355,7 +355,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<MergePatchJsonGetResponse, String>;
+    ) -> Result<MergePatchJsonGetResponse, ()>;
 
     /// Get some stuff..
     ///
@@ -365,7 +365,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<MultigetGetResponse, String>;
+    ) -> Result<MultigetGetResponse, ()>;
 
     /// MultipleAuthSchemeGet - GET /multiple_auth_scheme
     async fn multiple_auth_scheme_get(
@@ -373,7 +373,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<MultipleAuthSchemeGetResponse, String>;
+    ) -> Result<MultipleAuthSchemeGetResponse, ()>;
 
     /// MultiplePathParamsWithVeryLongPathToTestFormattingPathParamAPathParamBGet - GET /multiple-path-params-with-very-long-path-to-test-formatting/{path_param_a}/{path_param_b}
     async fn multiple_path_params_with_very_long_path_to_test_formatting_path_param_a_path_param_b_get(
@@ -382,10 +382,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         path_params: models::MultiplePathParamsWithVeryLongPathToTestFormattingPathParamAPathParamBGetPathParams,
-    ) -> Result<
-        MultiplePathParamsWithVeryLongPathToTestFormattingPathParamAPathParamBGetResponse,
-        String,
-    >;
+    ) -> Result<MultiplePathParamsWithVeryLongPathToTestFormattingPathParamAPathParamBGetResponse, ()>;
 
     /// OneOfGet - GET /one-of
     async fn one_of_get(
@@ -393,7 +390,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<OneOfGetResponse, String>;
+    ) -> Result<OneOfGetResponse, ()>;
 
     /// OverrideServerGet - GET /override-server
     async fn override_server_get(
@@ -401,7 +398,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<OverrideServerGetResponse, String>;
+    ) -> Result<OverrideServerGetResponse, ()>;
 
     /// Get some stuff with parameters..
     ///
@@ -412,7 +409,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::ParamgetGetQueryParams,
-    ) -> Result<ParamgetGetResponse, String>;
+    ) -> Result<ParamgetGetResponse, ()>;
 
     /// ReadonlyAuthSchemeGet - GET /readonly_auth_scheme
     async fn readonly_auth_scheme_get(
@@ -420,7 +417,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<ReadonlyAuthSchemeGetResponse, String>;
+    ) -> Result<ReadonlyAuthSchemeGetResponse, ()>;
 
     /// RegisterCallbackPost - POST /register-callback
     async fn register_callback_post(
@@ -429,7 +426,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         query_params: models::RegisterCallbackPostQueryParams,
-    ) -> Result<RegisterCallbackPostResponse, String>;
+    ) -> Result<RegisterCallbackPostResponse, ()>;
 
     /// RequiredOctetStreamPut - PUT /required_octet_stream
     async fn required_octet_stream_put(
@@ -438,7 +435,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<RequiredOctetStreamPutResponse, String>;
+    ) -> Result<RequiredOctetStreamPutResponse, ()>;
 
     /// ResponsesWithHeadersGet - GET /responses_with_headers
     async fn responses_with_headers_get(
@@ -446,7 +443,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<ResponsesWithHeadersGetResponse, String>;
+    ) -> Result<ResponsesWithHeadersGetResponse, ()>;
 
     /// Rfc7807Get - GET /rfc7807
     async fn rfc7807_get(
@@ -454,7 +451,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Rfc7807GetResponse, String>;
+    ) -> Result<Rfc7807GetResponse, ()>;
 
     /// TwoFirstLetterHeaders - POST /operation-two-first-letter-headers
     async fn two_first_letter_headers(
@@ -463,7 +460,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         header_params: models::TwoFirstLetterHeadersHeaderParams,
-    ) -> Result<TwoFirstLetterHeadersResponse, String>;
+    ) -> Result<TwoFirstLetterHeadersResponse, ()>;
 
     /// UntypedPropertyGet - GET /untyped_property
     async fn untyped_property_get(
@@ -472,7 +469,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Option<models::ObjectUntypedProps>,
-    ) -> Result<UntypedPropertyGetResponse, String>;
+    ) -> Result<UntypedPropertyGetResponse, ()>;
 
     /// UuidGet - GET /uuid
     async fn uuid_get(
@@ -480,7 +477,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<UuidGetResponse, String>;
+    ) -> Result<UuidGetResponse, ()>;
 
     /// XmlExtraPost - POST /xml_extra
     async fn xml_extra_post(
@@ -489,7 +486,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<XmlExtraPostResponse, String>;
+    ) -> Result<XmlExtraPostResponse, ()>;
 
     /// XmlOtherPost - POST /xml_other
     async fn xml_other_post(
@@ -498,7 +495,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<XmlOtherPostResponse, String>;
+    ) -> Result<XmlOtherPostResponse, ()>;
 
     /// XmlOtherPut - PUT /xml_other
     async fn xml_other_put(
@@ -507,7 +504,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<XmlOtherPutResponse, String>;
+    ) -> Result<XmlOtherPutResponse, ()>;
 
     /// Post an array.  It's important we test apostrophes, so include one here..
     ///
@@ -518,7 +515,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<XmlPostResponse, String>;
+    ) -> Result<XmlPostResponse, ()>;
 
     /// XmlPut - PUT /xml
     async fn xml_put(
@@ -527,5 +524,5 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: Bytes,
-    ) -> Result<XmlPutResponse, String>;
+    ) -> Result<XmlPutResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/info_repo.rs b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/info_repo.rs
index bd68394bf230..c73db4a16d43 100644
--- a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/info_repo.rs
+++ b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/info_repo.rs
@@ -26,5 +26,5 @@ pub trait InfoRepo {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetRepoInfoPathParams,
-    ) -> Result<GetRepoInfoResponse, String>;
+    ) -> Result<GetRepoInfoResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/repo.rs b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/repo.rs
index e08336d7799e..90d9a774f6e1 100644
--- a/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/repo.rs
+++ b/samples/server/petstore/rust-axum/output/openapi-v3/src/apis/repo.rs
@@ -26,5 +26,5 @@ pub trait Repo {
         host: Host,
         cookies: CookieJar,
         body: models::ObjectParam,
-    ) -> Result<CreateRepoResponse, String>;
+    ) -> Result<CreateRepoResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/ops-v3/src/apis/default.rs b/samples/server/petstore/rust-axum/output/ops-v3/src/apis/default.rs
index c24558c161db..387f4b3fa792 100644
--- a/samples/server/petstore/rust-axum/output/ops-v3/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/ops-v3/src/apis/default.rs
@@ -313,7 +313,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op10GetResponse, String>;
+    ) -> Result<Op10GetResponse, ()>;
 
     /// Op11Get - GET /op11
     async fn op11_get(
@@ -321,7 +321,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op11GetResponse, String>;
+    ) -> Result<Op11GetResponse, ()>;
 
     /// Op12Get - GET /op12
     async fn op12_get(
@@ -329,7 +329,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op12GetResponse, String>;
+    ) -> Result<Op12GetResponse, ()>;
 
     /// Op13Get - GET /op13
     async fn op13_get(
@@ -337,7 +337,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op13GetResponse, String>;
+    ) -> Result<Op13GetResponse, ()>;
 
     /// Op14Get - GET /op14
     async fn op14_get(
@@ -345,7 +345,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op14GetResponse, String>;
+    ) -> Result<Op14GetResponse, ()>;
 
     /// Op15Get - GET /op15
     async fn op15_get(
@@ -353,7 +353,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op15GetResponse, String>;
+    ) -> Result<Op15GetResponse, ()>;
 
     /// Op16Get - GET /op16
     async fn op16_get(
@@ -361,7 +361,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op16GetResponse, String>;
+    ) -> Result<Op16GetResponse, ()>;
 
     /// Op17Get - GET /op17
     async fn op17_get(
@@ -369,7 +369,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op17GetResponse, String>;
+    ) -> Result<Op17GetResponse, ()>;
 
     /// Op18Get - GET /op18
     async fn op18_get(
@@ -377,7 +377,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op18GetResponse, String>;
+    ) -> Result<Op18GetResponse, ()>;
 
     /// Op19Get - GET /op19
     async fn op19_get(
@@ -385,7 +385,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op19GetResponse, String>;
+    ) -> Result<Op19GetResponse, ()>;
 
     /// Op1Get - GET /op1
     async fn op1_get(
@@ -393,7 +393,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op1GetResponse, String>;
+    ) -> Result<Op1GetResponse, ()>;
 
     /// Op20Get - GET /op20
     async fn op20_get(
@@ -401,7 +401,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op20GetResponse, String>;
+    ) -> Result<Op20GetResponse, ()>;
 
     /// Op21Get - GET /op21
     async fn op21_get(
@@ -409,7 +409,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op21GetResponse, String>;
+    ) -> Result<Op21GetResponse, ()>;
 
     /// Op22Get - GET /op22
     async fn op22_get(
@@ -417,7 +417,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op22GetResponse, String>;
+    ) -> Result<Op22GetResponse, ()>;
 
     /// Op23Get - GET /op23
     async fn op23_get(
@@ -425,7 +425,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op23GetResponse, String>;
+    ) -> Result<Op23GetResponse, ()>;
 
     /// Op24Get - GET /op24
     async fn op24_get(
@@ -433,7 +433,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op24GetResponse, String>;
+    ) -> Result<Op24GetResponse, ()>;
 
     /// Op25Get - GET /op25
     async fn op25_get(
@@ -441,7 +441,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op25GetResponse, String>;
+    ) -> Result<Op25GetResponse, ()>;
 
     /// Op26Get - GET /op26
     async fn op26_get(
@@ -449,7 +449,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op26GetResponse, String>;
+    ) -> Result<Op26GetResponse, ()>;
 
     /// Op27Get - GET /op27
     async fn op27_get(
@@ -457,7 +457,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op27GetResponse, String>;
+    ) -> Result<Op27GetResponse, ()>;
 
     /// Op28Get - GET /op28
     async fn op28_get(
@@ -465,7 +465,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op28GetResponse, String>;
+    ) -> Result<Op28GetResponse, ()>;
 
     /// Op29Get - GET /op29
     async fn op29_get(
@@ -473,7 +473,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op29GetResponse, String>;
+    ) -> Result<Op29GetResponse, ()>;
 
     /// Op2Get - GET /op2
     async fn op2_get(
@@ -481,7 +481,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op2GetResponse, String>;
+    ) -> Result<Op2GetResponse, ()>;
 
     /// Op30Get - GET /op30
     async fn op30_get(
@@ -489,7 +489,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op30GetResponse, String>;
+    ) -> Result<Op30GetResponse, ()>;
 
     /// Op31Get - GET /op31
     async fn op31_get(
@@ -497,7 +497,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op31GetResponse, String>;
+    ) -> Result<Op31GetResponse, ()>;
 
     /// Op32Get - GET /op32
     async fn op32_get(
@@ -505,7 +505,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op32GetResponse, String>;
+    ) -> Result<Op32GetResponse, ()>;
 
     /// Op33Get - GET /op33
     async fn op33_get(
@@ -513,7 +513,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op33GetResponse, String>;
+    ) -> Result<Op33GetResponse, ()>;
 
     /// Op34Get - GET /op34
     async fn op34_get(
@@ -521,7 +521,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op34GetResponse, String>;
+    ) -> Result<Op34GetResponse, ()>;
 
     /// Op35Get - GET /op35
     async fn op35_get(
@@ -529,7 +529,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op35GetResponse, String>;
+    ) -> Result<Op35GetResponse, ()>;
 
     /// Op36Get - GET /op36
     async fn op36_get(
@@ -537,7 +537,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op36GetResponse, String>;
+    ) -> Result<Op36GetResponse, ()>;
 
     /// Op37Get - GET /op37
     async fn op37_get(
@@ -545,7 +545,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op37GetResponse, String>;
+    ) -> Result<Op37GetResponse, ()>;
 
     /// Op3Get - GET /op3
     async fn op3_get(
@@ -553,7 +553,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op3GetResponse, String>;
+    ) -> Result<Op3GetResponse, ()>;
 
     /// Op4Get - GET /op4
     async fn op4_get(
@@ -561,7 +561,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op4GetResponse, String>;
+    ) -> Result<Op4GetResponse, ()>;
 
     /// Op5Get - GET /op5
     async fn op5_get(
@@ -569,7 +569,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op5GetResponse, String>;
+    ) -> Result<Op5GetResponse, ()>;
 
     /// Op6Get - GET /op6
     async fn op6_get(
@@ -577,7 +577,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op6GetResponse, String>;
+    ) -> Result<Op6GetResponse, ()>;
 
     /// Op7Get - GET /op7
     async fn op7_get(
@@ -585,7 +585,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op7GetResponse, String>;
+    ) -> Result<Op7GetResponse, ()>;
 
     /// Op8Get - GET /op8
     async fn op8_get(
@@ -593,7 +593,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op8GetResponse, String>;
+    ) -> Result<Op8GetResponse, ()>;
 
     /// Op9Get - GET /op9
     async fn op9_get(
@@ -601,5 +601,5 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Op9GetResponse, String>;
+    ) -> Result<Op9GetResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/another_fake.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/another_fake.rs
index 99c6307abe80..f64e2e451bb9 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/another_fake.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/another_fake.rs
@@ -28,5 +28,5 @@ pub trait AnotherFake {
         host: Host,
         cookies: CookieJar,
         body: models::Client,
-    ) -> Result<TestSpecialTagsResponse, String>;
+    ) -> Result<TestSpecialTagsResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake.rs
index 38c5c477b253..22ad661101aa 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake.rs
@@ -125,7 +125,7 @@ pub trait Fake {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<Call123exampleResponse, String>;
+    ) -> Result<Call123exampleResponse, ()>;
 
     /// FakeOuterBooleanSerialize - POST /v2/fake/outer/boolean
     async fn fake_outer_boolean_serialize(
@@ -134,7 +134,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: Option<models::OuterBoolean>,
-    ) -> Result<FakeOuterBooleanSerializeResponse, String>;
+    ) -> Result<FakeOuterBooleanSerializeResponse, ()>;
 
     /// FakeOuterCompositeSerialize - POST /v2/fake/outer/composite
     async fn fake_outer_composite_serialize(
@@ -143,7 +143,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: Option<models::OuterComposite>,
-    ) -> Result<FakeOuterCompositeSerializeResponse, String>;
+    ) -> Result<FakeOuterCompositeSerializeResponse, ()>;
 
     /// FakeOuterNumberSerialize - POST /v2/fake/outer/number
     async fn fake_outer_number_serialize(
@@ -152,7 +152,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: Option<models::OuterNumber>,
-    ) -> Result<FakeOuterNumberSerializeResponse, String>;
+    ) -> Result<FakeOuterNumberSerializeResponse, ()>;
 
     /// FakeOuterStringSerialize - POST /v2/fake/outer/string
     async fn fake_outer_string_serialize(
@@ -161,7 +161,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: Option<models::OuterString>,
-    ) -> Result<FakeOuterStringSerializeResponse, String>;
+    ) -> Result<FakeOuterStringSerializeResponse, ()>;
 
     /// FakeResponseWithNumericalDescription - GET /v2/fake/response-with-numerical-description
     async fn fake_response_with_numerical_description(
@@ -169,7 +169,7 @@ pub trait Fake {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<FakeResponseWithNumericalDescriptionResponse, String>;
+    ) -> Result<FakeResponseWithNumericalDescriptionResponse, ()>;
 
     /// HyphenParam - GET /v2/fake/hyphenParam/{hyphen-param}
     async fn hyphen_param(
@@ -178,7 +178,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         path_params: models::HyphenParamPathParams,
-    ) -> Result<HyphenParamResponse, String>;
+    ) -> Result<HyphenParamResponse, ()>;
 
     /// TestBodyWithQueryParams - PUT /v2/fake/body-with-query-params
     async fn test_body_with_query_params(
@@ -188,7 +188,7 @@ pub trait Fake {
         cookies: CookieJar,
         query_params: models::TestBodyWithQueryParamsQueryParams,
         body: models::User,
-    ) -> Result<TestBodyWithQueryParamsResponse, String>;
+    ) -> Result<TestBodyWithQueryParamsResponse, ()>;
 
     /// To test \"client\" model.
     ///
@@ -199,7 +199,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: models::Client,
-    ) -> Result<TestClientModelResponse, String>;
+    ) -> Result<TestClientModelResponse, ()>;
 
     /// Fake endpoint for testing various parameters  假端點  偽のエンドポイント  가짜 엔드 포인트.
     ///
@@ -210,7 +210,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: models::TestEndpointParametersRequest,
-    ) -> Result<TestEndpointParametersResponse, String>;
+    ) -> Result<TestEndpointParametersResponse, ()>;
 
     /// To test enum parameters.
     ///
@@ -223,7 +223,7 @@ pub trait Fake {
         header_params: models::TestEnumParametersHeaderParams,
         query_params: models::TestEnumParametersQueryParams,
         body: Option<models::TestEnumParametersRequest>,
-    ) -> Result<TestEnumParametersResponse, String>;
+    ) -> Result<TestEnumParametersResponse, ()>;
 
     /// test inline additionalProperties.
     ///
@@ -234,7 +234,7 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: std::collections::HashMap<String, String>,
-    ) -> Result<TestInlineAdditionalPropertiesResponse, String>;
+    ) -> Result<TestInlineAdditionalPropertiesResponse, ()>;
 
     /// test json serialization of form data.
     ///
@@ -245,5 +245,5 @@ pub trait Fake {
         host: Host,
         cookies: CookieJar,
         body: models::TestJsonFormDataRequest,
-    ) -> Result<TestJsonFormDataResponse, String>;
+    ) -> Result<TestJsonFormDataResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake_classname_tags123.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake_classname_tags123.rs
index dbc5f4b6184f..100f9dc7ad59 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake_classname_tags123.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/fake_classname_tags123.rs
@@ -28,5 +28,5 @@ pub trait FakeClassnameTags123 {
         host: Host,
         cookies: CookieJar,
         body: models::Client,
-    ) -> Result<TestClassnameResponse, String>;
+    ) -> Result<TestClassnameResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/pet.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/pet.rs
index 169b621ede09..05bb94bdfe44 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/pet.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/pet.rs
@@ -96,7 +96,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         body: models::Pet,
-    ) -> Result<AddPetResponse, String>;
+    ) -> Result<AddPetResponse, ()>;
 
     /// Deletes a pet.
     ///
@@ -108,7 +108,7 @@ pub trait Pet {
         cookies: CookieJar,
         header_params: models::DeletePetHeaderParams,
         path_params: models::DeletePetPathParams,
-    ) -> Result<DeletePetResponse, String>;
+    ) -> Result<DeletePetResponse, ()>;
 
     /// Finds Pets by status.
     ///
@@ -119,7 +119,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         query_params: models::FindPetsByStatusQueryParams,
-    ) -> Result<FindPetsByStatusResponse, String>;
+    ) -> Result<FindPetsByStatusResponse, ()>;
 
     /// Finds Pets by tags.
     ///
@@ -130,7 +130,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         query_params: models::FindPetsByTagsQueryParams,
-    ) -> Result<FindPetsByTagsResponse, String>;
+    ) -> Result<FindPetsByTagsResponse, ()>;
 
     /// Find pet by ID.
     ///
@@ -142,7 +142,7 @@ pub trait Pet {
         cookies: CookieJar,
         token_in_header: Option<String>,
         path_params: models::GetPetByIdPathParams,
-    ) -> Result<GetPetByIdResponse, String>;
+    ) -> Result<GetPetByIdResponse, ()>;
 
     /// Update an existing pet.
     ///
@@ -153,7 +153,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         body: models::Pet,
-    ) -> Result<UpdatePetResponse, String>;
+    ) -> Result<UpdatePetResponse, ()>;
 
     /// Updates a pet in the store with form data.
     ///
@@ -165,7 +165,7 @@ pub trait Pet {
         cookies: CookieJar,
         path_params: models::UpdatePetWithFormPathParams,
         body: Option<models::UpdatePetWithFormRequest>,
-    ) -> Result<UpdatePetWithFormResponse, String>;
+    ) -> Result<UpdatePetWithFormResponse, ()>;
 
     /// uploads an image.
     ///
@@ -177,5 +177,5 @@ pub trait Pet {
         cookies: CookieJar,
         path_params: models::UploadFilePathParams,
         body: Multipart,
-    ) -> Result<UploadFileResponse, String>;
+    ) -> Result<UploadFileResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/store.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/store.rs
index 3616cc511a32..371f49d4ebe2 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/store.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/store.rs
@@ -60,7 +60,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         path_params: models::DeleteOrderPathParams,
-    ) -> Result<DeleteOrderResponse, String>;
+    ) -> Result<DeleteOrderResponse, ()>;
 
     /// Returns pet inventories by status.
     ///
@@ -71,7 +71,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         token_in_header: Option<String>,
-    ) -> Result<GetInventoryResponse, String>;
+    ) -> Result<GetInventoryResponse, ()>;
 
     /// Find purchase order by ID.
     ///
@@ -82,7 +82,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetOrderByIdPathParams,
-    ) -> Result<GetOrderByIdResponse, String>;
+    ) -> Result<GetOrderByIdResponse, ()>;
 
     /// Place an order for a pet.
     ///
@@ -93,5 +93,5 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         body: models::Order,
-    ) -> Result<PlaceOrderResponse, String>;
+    ) -> Result<PlaceOrderResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/user.rs b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/user.rs
index ba3e68d8424d..1aa623644320 100644
--- a/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/user.rs
+++ b/samples/server/petstore/rust-axum/output/petstore-with-fake-endpoints-models-for-testing/src/apis/user.rs
@@ -98,7 +98,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         body: models::User,
-    ) -> Result<CreateUserResponse, String>;
+    ) -> Result<CreateUserResponse, ()>;
 
     /// Creates list of users with given input array.
     ///
@@ -109,7 +109,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         body: Vec<models::User>,
-    ) -> Result<CreateUsersWithArrayInputResponse, String>;
+    ) -> Result<CreateUsersWithArrayInputResponse, ()>;
 
     /// Creates list of users with given input array.
     ///
@@ -120,7 +120,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         body: Vec<models::User>,
-    ) -> Result<CreateUsersWithListInputResponse, String>;
+    ) -> Result<CreateUsersWithListInputResponse, ()>;
 
     /// Delete user.
     ///
@@ -131,7 +131,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         path_params: models::DeleteUserPathParams,
-    ) -> Result<DeleteUserResponse, String>;
+    ) -> Result<DeleteUserResponse, ()>;
 
     /// Get user by user name.
     ///
@@ -142,7 +142,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetUserByNamePathParams,
-    ) -> Result<GetUserByNameResponse, String>;
+    ) -> Result<GetUserByNameResponse, ()>;
 
     /// Logs user into the system.
     ///
@@ -153,7 +153,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         query_params: models::LoginUserQueryParams,
-    ) -> Result<LoginUserResponse, String>;
+    ) -> Result<LoginUserResponse, ()>;
 
     /// Logs out current logged in user session.
     ///
@@ -163,7 +163,7 @@ pub trait User {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<LogoutUserResponse, String>;
+    ) -> Result<LogoutUserResponse, ()>;
 
     /// Updated user.
     ///
@@ -175,5 +175,5 @@ pub trait User {
         cookies: CookieJar,
         path_params: models::UpdateUserPathParams,
         body: models::User,
-    ) -> Result<UpdateUserResponse, String>;
+    ) -> Result<UpdateUserResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore/src/apis/pet.rs b/samples/server/petstore/rust-axum/output/petstore/src/apis/pet.rs
index 92335fa4400c..bedaffceeb74 100644
--- a/samples/server/petstore/rust-axum/output/petstore/src/apis/pet.rs
+++ b/samples/server/petstore/rust-axum/output/petstore/src/apis/pet.rs
@@ -100,7 +100,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         body: models::Pet,
-    ) -> Result<AddPetResponse, String>;
+    ) -> Result<AddPetResponse, ()>;
 
     /// Deletes a pet.
     ///
@@ -112,7 +112,7 @@ pub trait Pet {
         cookies: CookieJar,
         header_params: models::DeletePetHeaderParams,
         path_params: models::DeletePetPathParams,
-    ) -> Result<DeletePetResponse, String>;
+    ) -> Result<DeletePetResponse, ()>;
 
     /// Finds Pets by status.
     ///
@@ -123,7 +123,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         query_params: models::FindPetsByStatusQueryParams,
-    ) -> Result<FindPetsByStatusResponse, String>;
+    ) -> Result<FindPetsByStatusResponse, ()>;
 
     /// Finds Pets by tags.
     ///
@@ -134,7 +134,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         query_params: models::FindPetsByTagsQueryParams,
-    ) -> Result<FindPetsByTagsResponse, String>;
+    ) -> Result<FindPetsByTagsResponse, ()>;
 
     /// Find pet by ID.
     ///
@@ -146,7 +146,7 @@ pub trait Pet {
         cookies: CookieJar,
         token_in_header: Option<String>,
         path_params: models::GetPetByIdPathParams,
-    ) -> Result<GetPetByIdResponse, String>;
+    ) -> Result<GetPetByIdResponse, ()>;
 
     /// Update an existing pet.
     ///
@@ -157,7 +157,7 @@ pub trait Pet {
         host: Host,
         cookies: CookieJar,
         body: models::Pet,
-    ) -> Result<UpdatePetResponse, String>;
+    ) -> Result<UpdatePetResponse, ()>;
 
     /// Updates a pet in the store with form data.
     ///
@@ -169,7 +169,7 @@ pub trait Pet {
         cookies: CookieJar,
         path_params: models::UpdatePetWithFormPathParams,
         body: Option<models::UpdatePetWithFormRequest>,
-    ) -> Result<UpdatePetWithFormResponse, String>;
+    ) -> Result<UpdatePetWithFormResponse, ()>;
 
     /// uploads an image.
     ///
@@ -181,5 +181,5 @@ pub trait Pet {
         cookies: CookieJar,
         path_params: models::UploadFilePathParams,
         body: Multipart,
-    ) -> Result<UploadFileResponse, String>;
+    ) -> Result<UploadFileResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore/src/apis/store.rs b/samples/server/petstore/rust-axum/output/petstore/src/apis/store.rs
index 85093df815ba..555aba9d894e 100644
--- a/samples/server/petstore/rust-axum/output/petstore/src/apis/store.rs
+++ b/samples/server/petstore/rust-axum/output/petstore/src/apis/store.rs
@@ -60,7 +60,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         path_params: models::DeleteOrderPathParams,
-    ) -> Result<DeleteOrderResponse, String>;
+    ) -> Result<DeleteOrderResponse, ()>;
 
     /// Returns pet inventories by status.
     ///
@@ -71,7 +71,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         token_in_header: Option<String>,
-    ) -> Result<GetInventoryResponse, String>;
+    ) -> Result<GetInventoryResponse, ()>;
 
     /// Find purchase order by ID.
     ///
@@ -82,7 +82,7 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetOrderByIdPathParams,
-    ) -> Result<GetOrderByIdResponse, String>;
+    ) -> Result<GetOrderByIdResponse, ()>;
 
     /// Place an order for a pet.
     ///
@@ -93,5 +93,5 @@ pub trait Store {
         host: Host,
         cookies: CookieJar,
         body: models::Order,
-    ) -> Result<PlaceOrderResponse, String>;
+    ) -> Result<PlaceOrderResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/petstore/src/apis/user.rs b/samples/server/petstore/rust-axum/output/petstore/src/apis/user.rs
index 3d8846495695..ae7a2373f196 100644
--- a/samples/server/petstore/rust-axum/output/petstore/src/apis/user.rs
+++ b/samples/server/petstore/rust-axum/output/petstore/src/apis/user.rs
@@ -100,7 +100,7 @@ pub trait User {
         cookies: CookieJar,
         token_in_header: Option<String>,
         body: models::User,
-    ) -> Result<CreateUserResponse, String>;
+    ) -> Result<CreateUserResponse, ()>;
 
     /// Creates list of users with given input array.
     ///
@@ -112,7 +112,7 @@ pub trait User {
         cookies: CookieJar,
         token_in_header: Option<String>,
         body: Vec<models::User>,
-    ) -> Result<CreateUsersWithArrayInputResponse, String>;
+    ) -> Result<CreateUsersWithArrayInputResponse, ()>;
 
     /// Creates list of users with given input array.
     ///
@@ -124,7 +124,7 @@ pub trait User {
         cookies: CookieJar,
         token_in_header: Option<String>,
         body: Vec<models::User>,
-    ) -> Result<CreateUsersWithListInputResponse, String>;
+    ) -> Result<CreateUsersWithListInputResponse, ()>;
 
     /// Delete user.
     ///
@@ -136,7 +136,7 @@ pub trait User {
         cookies: CookieJar,
         token_in_header: Option<String>,
         path_params: models::DeleteUserPathParams,
-    ) -> Result<DeleteUserResponse, String>;
+    ) -> Result<DeleteUserResponse, ()>;
 
     /// Get user by user name.
     ///
@@ -147,7 +147,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         path_params: models::GetUserByNamePathParams,
-    ) -> Result<GetUserByNameResponse, String>;
+    ) -> Result<GetUserByNameResponse, ()>;
 
     /// Logs user into the system.
     ///
@@ -158,7 +158,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         query_params: models::LoginUserQueryParams,
-    ) -> Result<LoginUserResponse, String>;
+    ) -> Result<LoginUserResponse, ()>;
 
     /// Logs out current logged in user session.
     ///
@@ -169,7 +169,7 @@ pub trait User {
         host: Host,
         cookies: CookieJar,
         token_in_header: Option<String>,
-    ) -> Result<LogoutUserResponse, String>;
+    ) -> Result<LogoutUserResponse, ()>;
 
     /// Updated user.
     ///
@@ -182,5 +182,5 @@ pub trait User {
         token_in_header: Option<String>,
         path_params: models::UpdateUserPathParams,
         body: models::User,
-    ) -> Result<UpdateUserResponse, String>;
+    ) -> Result<UpdateUserResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/ping-bearer-auth/src/apis/default.rs b/samples/server/petstore/rust-axum/output/ping-bearer-auth/src/apis/default.rs
index 3608ffa65572..cfb12ef7fd4d 100644
--- a/samples/server/petstore/rust-axum/output/ping-bearer-auth/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/ping-bearer-auth/src/apis/default.rs
@@ -25,5 +25,5 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<PingGetResponse, String>;
+    ) -> Result<PingGetResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/rust-axum-header-uuid/src/apis/default.rs b/samples/server/petstore/rust-axum/output/rust-axum-header-uuid/src/apis/default.rs
index cd590f6819ac..2c6c51c0d2c3 100644
--- a/samples/server/petstore/rust-axum/output/rust-axum-header-uuid/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/rust-axum-header-uuid/src/apis/default.rs
@@ -26,5 +26,5 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         header_params: models::UsersPostHeaderParams,
-    ) -> Result<UsersPostResponse, String>;
+    ) -> Result<UsersPostResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/rust-axum-test/src/apis/default.rs b/samples/server/petstore/rust-axum/output/rust-axum-test/src/apis/default.rs
index 08985bd64e59..ba643a1d2f82 100644
--- a/samples/server/petstore/rust-axum/output/rust-axum-test/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/rust-axum-test/src/apis/default.rs
@@ -89,7 +89,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<AllOfGetResponse, String>;
+    ) -> Result<AllOfGetResponse, ()>;
 
     /// A dummy endpoint to make the spec valid..
     ///
@@ -99,7 +99,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<DummyGetResponse, String>;
+    ) -> Result<DummyGetResponse, ()>;
 
     /// DummyPut - PUT /dummy
     async fn dummy_put(
@@ -108,7 +108,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: models::FooDummyPutRequest,
-    ) -> Result<DummyPutResponse, String>;
+    ) -> Result<DummyPutResponse, ()>;
 
     /// Get a file.
     ///
@@ -118,7 +118,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<FileResponseGetResponse, String>;
+    ) -> Result<FileResponseGetResponse, ()>;
 
     /// GetStructuredYaml - GET /get-structured-yaml
     async fn get_structured_yaml(
@@ -126,7 +126,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<GetStructuredYamlResponse, String>;
+    ) -> Result<GetStructuredYamlResponse, ()>;
 
     /// Test HTML handling.
     ///
@@ -137,7 +137,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: String,
-    ) -> Result<HtmlPostResponse, String>;
+    ) -> Result<HtmlPostResponse, ()>;
 
     /// PostYaml - POST /post-yaml
     async fn post_yaml(
@@ -146,7 +146,7 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: String,
-    ) -> Result<PostYamlResponse, String>;
+    ) -> Result<PostYamlResponse, ()>;
 
     /// Get an arbitrary JSON blob..
     ///
@@ -156,7 +156,7 @@ pub trait Default {
         method: Method,
         host: Host,
         cookies: CookieJar,
-    ) -> Result<RawJsonGetResponse, String>;
+    ) -> Result<RawJsonGetResponse, ()>;
 
     /// Send an arbitrary JSON blob.
     ///
@@ -167,5 +167,5 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: crate::types::Object,
-    ) -> Result<SoloObjectPostResponse, String>;
+    ) -> Result<SoloObjectPostResponse, ()>;
 }
diff --git a/samples/server/petstore/rust-axum/output/rust-axum-validation-test/src/apis/default.rs b/samples/server/petstore/rust-axum/output/rust-axum-validation-test/src/apis/default.rs
index a5b9394198a1..d9ef3904a0ca 100644
--- a/samples/server/petstore/rust-axum/output/rust-axum-validation-test/src/apis/default.rs
+++ b/samples/server/petstore/rust-axum/output/rust-axum-validation-test/src/apis/default.rs
@@ -26,5 +26,5 @@ pub trait Default {
         host: Host,
         cookies: CookieJar,
         body: models::Email,
-    ) -> Result<MailPutResponse, String>;
+    ) -> Result<MailPutResponse, ()>;
 }