OpenAPITools · wing328 · Nov 13, 2025 · Nov 2, 2021
diff --git a/...openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java b/...openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java
@@ -870,6 +870,16 @@ private void postProcessOperationWithModels(CodegenOperation op, List<ModelMap>
             op.vendorExtensions.put("x-has-request-body", true);
         }
 
+        if (op.allParams.stream()
+            .anyMatch(p -> p.isArray && !p.isPrimitiveType)) {
+            op.vendorExtensions.put("x-has-borrowed-params", Boolean.TRUE);
+            for (CodegenParameter param : op.allParams) {
+                if (param.isArray) {
+                    param.vendorExtensions.put("x-param-needs-lifetime", Boolean.TRUE);
+                }
+            }
+        }
+
         // The CLI generates a structopt structure for each operation. This can only have a single
         // use of a short option, which comes from the parameter name, so we need to police
         // against duplicates

diff --git a/modules/openapi-generator/src/main/resources/rust-server/Cargo.mustache b/modules/openapi-generator/src/main/resources/rust-server/Cargo.mustache
@@ -70,6 +70,8 @@ cli = [
 ]
 conversion = ["frunk", "frunk_derives", "frunk_core", "frunk-enum-core", "frunk-enum-derive"]
 
+mock = ["mockall"]
+
 [target.'cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))'.dependencies]
 native-tls = { version = "0.2", optional = true }
 hyper-tls = { version = "0.6", optional = true }
@@ -87,6 +89,7 @@ swagger = { version = "7.0.0-rc2", features = ["serdejson", "server", "client",
 headers = "0.4.0"
 log = "0.4.27"
 mime = "0.3"
+mockall = { version = "0.13.1", optional = true }
 
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

diff --git a/modules/openapi-generator/src/main/resources/rust-server/client-operation.mustache b/modules/openapi-generator/src/main/resources/rust-server/client-operation.mustache
@@ -1,13 +1,13 @@
     #[allow(clippy::vec_init_then_push)]
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#exts}}
   {{#x-callback-params}}
         callback_{{.}}: String,
   {{/x-callback-params}}
 {{/exts}}
 {{#allParams}}
-        param_{{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        param_{{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         context: &C) -> Result<{{{operationId}}}Response, ApiError>
     {

diff --git a/modules/openapi-generator/src/main/resources/rust-server/example-server-operation.mustache b/modules/openapi-generator/src/main/resources/rust-server/example-server-operation.mustache
@@ -1,15 +1,15 @@
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#exts}}
   {{#x-callback-params}}
         callback_{{.}}: String,
   {{/x-callback-params}}
 {{/exts}}
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         context: &C) -> Result<{{{operationId}}}Response, ApiError>
     {

diff --git a/modules/openapi-generator/src/main/resources/rust-server/lib.mustache b/modules/openapi-generator/src/main/resources/rust-server/lib.mustache
@@ -3,6 +3,8 @@
 
 use async_trait::async_trait;
 use futures::Stream;
+#[cfg(feature = "mock")]
+use mockall::automock;
 use std::error::Error;
 use std::collections::BTreeSet;
 use std::task::{Poll, Context};
@@ -33,6 +35,7 @@ pub use auth::{AuthenticationApi, Claims};
   {{/apis}}
 {{/apiInfo}}
 /// API
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait Api<C: Send + Sync> {
@@ -43,10 +46,10 @@ pub trait Api<C: Send + Sync> {
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         context: &C) -> Result<{{{operationId}}}Response, ApiError>;
 
@@ -57,9 +60,14 @@ pub trait Api<C: Send + Sync> {
 }
 
 /// API where `Context` isn't passed on every API call
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait ApiNoContext<C: Send + Sync> {
+    // The std::task::Context struct houses a reference to std::task::Waker with the lifetime <'a>.
+    // Adding an anonymous lifetime `'a` to allow mockall to create a mock object with the right lifetimes.
+    // This is needed because the compiler is unable to determine the lifetimes on F's trait bound
+    // where F is the closure created by mockall. We use higher-rank trait bounds here to get around this.
 
     fn context(&self) -> &C;
 
@@ -70,10 +78,10 @@ pub trait ApiNoContext<C: Send + Sync> {
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         ) -> Result<{{{operationId}}}Response, ApiError>;
 
@@ -109,10 +117,10 @@ impl<T: Api<C> + Send + Sync, C: Clone + Send + Sync> ApiNoContext<C> for Contex
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         ) -> Result<{{{operationId}}}Response, ApiError>
     {
@@ -146,6 +154,7 @@ impl<T: Api<C> + Send + Sync, C: Clone + Send + Sync> ApiNoContext<C> for Contex
 {{/apiInfo}}
 
 /// Callback API
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 pub trait CallbackApi<C: Send + Sync> {
 
@@ -159,15 +168,15 @@ pub trait CallbackApi<C: Send + Sync> {
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#exts}}
   {{#x-callback-params}}
         callback_{{.}}: String,
   {{/x-callback-params}}
 {{/exts}}
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         context: &C) -> Result<{{{operationId}}}Response, ApiError>;
 
@@ -181,6 +190,7 @@ pub trait CallbackApi<C: Send + Sync> {
 }
 
 /// Callback API without a `Context`
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 pub trait CallbackApiNoContext<C: Send + Sync> {
 
@@ -196,15 +206,15 @@ pub trait CallbackApiNoContext<C: Send + Sync> {
 {{#summary}}
     /// {{{.}}}
 {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#exts}}
   {{#x-callback-params}}
         callback_{{.}}: String,
   {{/x-callback-params}}
 {{/exts}}
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         ) -> Result<{{{operationId}}}Response, ApiError>;
 
@@ -246,15 +256,15 @@ impl<T: CallbackApi<C> + Send + Sync, C: Clone + Send + Sync> CallbackApiNoConte
               {{#summary}}
     /// {{{.}}}
               {{/summary}}
-    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}(
+    async fn {{#exts}}{{{x-operation-id}}}{{/exts}}{{#exts.x-has-borrowed-params}}<'a>{{/exts.x-has-borrowed-params}}(
         &self,
 {{#exts}}
   {{#x-callback-params}}
         callback_{{.}}: String,
   {{/x-callback-params}}
 {{/exts}}
 {{#allParams}}
-        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{{dataType}}}{{^required}}>{{/required}},
+        {{{paramName}}}: {{^required}}Option<{{/required}}{{#isArray}}&{{/isArray}}{{#exts.x-param-needs-lifetime}}'a {{/exts.x-param-needs-lifetime}}{{{dataType}}}{{^required}}>{{/required}},
 {{/allParams}}
         ) -> Result<{{{operationId}}}Response, ApiError>
     {

diff --git a/samples/server/petstore/rust-server/output/multipart-v3/Cargo.toml b/samples/server/petstore/rust-server/output/multipart-v3/Cargo.toml
@@ -24,6 +24,8 @@ cli = [
 ]
 conversion = ["frunk", "frunk_derives", "frunk_core", "frunk-enum-core", "frunk-enum-derive"]
 
+mock = ["mockall"]
+
 [target.'cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))'.dependencies]
 native-tls = { version = "0.2", optional = true }
 hyper-tls = { version = "0.6", optional = true }
@@ -41,6 +43,7 @@ swagger = { version = "7.0.0-rc2", features = ["serdejson", "server", "client",
 headers = "0.4.0"
 log = "0.4.27"
 mime = "0.3"
+mockall = { version = "0.13.1", optional = true }
 
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

diff --git a/samples/server/petstore/rust-server/output/multipart-v3/src/lib.rs b/samples/server/petstore/rust-server/output/multipart-v3/src/lib.rs
@@ -3,6 +3,8 @@
 
 use async_trait::async_trait;
 use futures::Stream;
+#[cfg(feature = "mock")]
+use mockall::automock;
 use std::error::Error;
 use std::collections::BTreeSet;
 use std::task::{Poll, Context};
@@ -39,6 +41,7 @@ pub enum MultipleIdenticalMimeTypesPostResponse {
 }
 
 /// API
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait Api<C: Send + Sync> {
@@ -66,9 +69,14 @@ pub trait Api<C: Send + Sync> {
 }
 
 /// API where `Context` isn't passed on every API call
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait ApiNoContext<C: Send + Sync> {
+    // The std::task::Context struct houses a reference to std::task::Waker with the lifetime <'a>.
+    // Adding an anonymous lifetime `'a` to allow mockall to create a mock object with the right lifetimes.
+    // This is needed because the compiler is unable to determine the lifetimes on F's trait bound
+    // where F is the closure created by mockall. We use higher-rank trait bounds here to get around this.
 
     fn context(&self) -> &C;
 

diff --git a/samples/server/petstore/rust-server/output/no-example-v3/Cargo.toml b/samples/server/petstore/rust-server/output/no-example-v3/Cargo.toml
@@ -20,6 +20,8 @@ cli = [
 ]
 conversion = ["frunk", "frunk_derives", "frunk_core", "frunk-enum-core", "frunk-enum-derive"]
 
+mock = ["mockall"]
+
 [target.'cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))'.dependencies]
 native-tls = { version = "0.2", optional = true }
 hyper-tls = { version = "0.6", optional = true }
@@ -37,6 +39,7 @@ swagger = { version = "7.0.0-rc2", features = ["serdejson", "server", "client",
 headers = "0.4.0"
 log = "0.4.27"
 mime = "0.3"
+mockall = { version = "0.13.1", optional = true }
 
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

diff --git a/samples/server/petstore/rust-server/output/no-example-v3/src/lib.rs b/samples/server/petstore/rust-server/output/no-example-v3/src/lib.rs
@@ -3,6 +3,8 @@
 
 use async_trait::async_trait;
 use futures::Stream;
+#[cfg(feature = "mock")]
+use mockall::automock;
 use std::error::Error;
 use std::collections::BTreeSet;
 use std::task::{Poll, Context};
@@ -27,6 +29,7 @@ pub enum OpGetResponse {
 }
 
 /// API
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait Api<C: Send + Sync> {
@@ -38,9 +41,14 @@ pub trait Api<C: Send + Sync> {
 }
 
 /// API where `Context` isn't passed on every API call
+#[cfg_attr(feature = "mock", automock)]
 #[async_trait]
 #[allow(clippy::too_many_arguments, clippy::ptr_arg)]
 pub trait ApiNoContext<C: Send + Sync> {
+    // The std::task::Context struct houses a reference to std::task::Waker with the lifetime <'a>.
+    // Adding an anonymous lifetime `'a` to allow mockall to create a mock object with the right lifetimes.
+    // This is needed because the compiler is unable to determine the lifetimes on F's trait bound
+    // where F is the closure created by mockall. We use higher-rank trait bounds here to get around this.
 
     fn context(&self) -> &C;
 

diff --git a/samples/server/petstore/rust-server/output/openapi-v3/Cargo.toml b/samples/server/petstore/rust-server/output/openapi-v3/Cargo.toml
@@ -23,6 +23,8 @@ cli = [
 ]
 conversion = ["frunk", "frunk_derives", "frunk_core", "frunk-enum-core", "frunk-enum-derive"]
 
+mock = ["mockall"]
+
 [target.'cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))'.dependencies]
 native-tls = { version = "0.2", optional = true }
 hyper-tls = { version = "0.6", optional = true }
@@ -40,6 +42,7 @@ swagger = { version = "7.0.0-rc2", features = ["serdejson", "server", "client",
 headers = "0.4.0"
 log = "0.4.27"
 mime = "0.3"
+mockall = { version = "0.13.1", optional = true }
 
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

diff --git a/samples/server/petstore/rust-server/output/openapi-v3/examples/server/server.rs b/samples/server/petstore/rust-server/output/openapi-v3/examples/server/server.rs
@@ -176,9 +176,9 @@ use swagger::ApiError;
 #[async_trait]
 impl<C> Api<C> for Server<C> where C: Has<XSpanIdString> + Send + Sync
 {
-    async fn any_of_get(
+    async fn any_of_get<'a>(
         &self,
-        any_of: Option<&Vec<models::AnyOfObject>>,
+        any_of: Option<&'a Vec<models::AnyOfObject>>,
         context: &C) -> Result<AnyOfGetResponse, ApiError>
     {
         info!("any_of_get({:?}) - X-Span-ID: {:?}", any_of, context.get().0.clone());
@@ -194,29 +194,29 @@ impl<C> Api<C> for Server<C> where C: Has<XSpanIdString> + Send + Sync
         Err(ApiError("Api-Error: Operation is NOT implemented".into()))
     }
 
-    async fn complex_query_param_get(
+    async fn complex_query_param_get<'a>(
         &self,
-        list_of_strings: Option<&Vec<models::StringObject>>,
+        list_of_strings: Option<&'a Vec<models::StringObject>>,
         context: &C) -> Result<ComplexQueryParamGetResponse, ApiError>
     {
         info!("complex_query_param_get({:?}) - X-Span-ID: {:?}", list_of_strings, context.get().0.clone());
         Err(ApiError("Api-Error: Operation is NOT implemented".into()))
     }
 
     /// Test examples
-    async fn examples_test(
+    async fn examples_test<'a>(
         &self,
-        ids: Option<&Vec<String>>,
+        ids: Option<&'a Vec<String>>,
         context: &C) -> Result<ExamplesTestResponse, ApiError>
     {
         info!("examples_test({:?}) - X-Span-ID: {:?}", ids, context.get().0.clone());
         Err(ApiError("Api-Error: Operation is NOT implemented".into()))
     }
 
     /// Test a Form Post
-    async fn form_test(
+    async fn form_test<'a>(
         &self,
-        required_array: &Vec<String>,
+        required_array: &'a Vec<String>,
         enum_field: models::FormTestRequestEnumField,
         context: &C) -> Result<FormTestResponse, ApiError>
     {
@@ -233,9 +233,9 @@ impl<C> Api<C> for Server<C> where C: Has<XSpanIdString> + Send + Sync
         Err(ApiError("Api-Error: Operation is NOT implemented".into()))
     }
 
-    async fn json_complex_query_param_get(
+    async fn json_complex_query_param_get<'a>(
         &self,
-        list_of_strings: Option<&Vec<models::StringObject>>,
+        list_of_strings: Option<&'a Vec<models::StringObject>>,
         context: &C) -> Result<JsonComplexQueryParamGetResponse, ApiError>
     {
         info!("json_complex_query_param_get({:?}) - X-Span-ID: {:?}", list_of_strings, context.get().0.clone());