Rust: Support Integer enums using Serde_repr (#19199)

* rust: support repr(int) enum

* Regen APIS

* remove the extra lines

* merge most recent commits from master

* update tests to ensure that enum compiles correctly

* drop changes to kotlin files

---------

Co-authored-by: Jihyun Yu <[email protected]>

Author: bertkdowns

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

@@ -37,6 +37,7 @@ serde = { version = "^1.0", features = ["derive"] }
 serde_with = { version = "^3.8", default-features = false, features = ["base64", "std", "macros"] }
 {{/serdeWith}}
 serde_json = "^1.0"
+serde_repr = "^0.1"
 url = "^2.5"
 uuid = { version = "^1.8", features = ["serde", "v4"] }
 {{#hyper}}

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

@@ -1,6 +1,7 @@
 #![allow(unused_imports)]
 #![allow(clippy::too_many_arguments)]
 
+extern crate serde_repr;
 extern crate serde;
 extern crate serde_json;
 extern crate url;

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

@@ -6,11 +6,43 @@ use serde::{Deserialize, Serialize};
 {{^isEnum}}{{#vendorExtensions.x-rust-has-byte-array}}
 use serde_with::serde_as;
 {{/vendorExtensions.x-rust-has-byte-array}}{{/isEnum}}
+{{#isEnum}}
+{{#isInteger}}
+use serde_repr::{Serialize_repr,Deserialize_repr};
+{{/isInteger}}
+{{/isEnum}}
 {{#description}}
 /// {{{classname}}} : {{{description}}}
 {{/description}}
+{{!-- for repr(int) enum schemas --}}
+{{#isEnum}}
+{{#isInteger}}
+/// {{{description}}}
+#[repr(i64)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize_repr, Deserialize_repr)]
+pub enum {{{classname}}} {
+{{#allowableValues}}
+{{#enumVars}}
+    {{{name}}} = {{{value}}},
+{{/enumVars}}{{/allowableValues}}
+}
+
+impl ToString for {{{classname}}} {
+    fn to_string(&self) -> String {
+        match self {
+            {{#allowableValues}}
+            {{#enumVars}}
+            Self::{{{name}}} => String::from("{{{value}}}"),
+            {{/enumVars}}
+            {{/allowableValues}}
+        }
+    }
+}
+{{/isInteger}}
+{{/isEnum}}
 {{!-- for enum schemas --}}
 {{#isEnum}}
+{{^isInteger}}
 /// {{{description}}}
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
 pub enum {{{classname}}} {
@@ -33,6 +65,7 @@ impl std::fmt::Display for {{{classname}}} {
     }
 }
 
+{{/isInteger}}
 impl Default for {{{classname}}} {
     fn default() -> {{{classname}}} {
         {{#allowableValues}}

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

@@ -959,6 +959,14 @@ components:
           nullable: true
         just_string:
           type: string
+    NumericEnumTesting:
+      description: testing that numeric enums are converted correctly
+      enum:
+        - 0
+        - 1
+        - 2
+        - 3
+      type: integer
     ref:
       description: using reserved word as model name
       type: object

samples/client/others/rust/hyper/api-with-ref-param/Cargo.toml

@@ -10,6 +10,7 @@ edition = "2021"
 [dependencies]
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = "^1.0"
+serde_repr = "^0.1"
 url = "^2.5"
 uuid = { version = "^1.8", features = ["serde", "v4"] }
 hyper = { version = "^1.3.1", features = ["full"] }

samples/client/others/rust/hyper/api-with-ref-param/src/lib.rs

@@ -1,6 +1,7 @@
 #![allow(unused_imports)]
 #![allow(clippy::too_many_arguments)]
 
+extern crate serde_repr;
 extern crate serde;
 extern crate serde_json;
 extern crate url;

samples/client/others/rust/hyper/composed-oneof/Cargo.toml

@@ -10,6 +10,7 @@ edition = "2021"
 [dependencies]
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = "^1.0"
+serde_repr = "^0.1"
 url = "^2.5"
 uuid = { version = "^1.8", features = ["serde", "v4"] }
 hyper = { version = "^1.3.1", features = ["full"] }

samples/client/others/rust/hyper/composed-oneof/src/lib.rs

@@ -1,6 +1,7 @@
 #![allow(unused_imports)]
 #![allow(clippy::too_many_arguments)]
 
+extern crate serde_repr;
 extern crate serde;
 extern crate serde_json;
 extern crate url;

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

@@ -10,6 +10,7 @@ edition = "2021"
 [dependencies]
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = "^1.0"
+serde_repr = "^0.1"
 url = "^2.5"
 uuid = { version = "^1.8", features = ["serde", "v4"] }
 hyper = { version = "^1.3.1", features = ["full"] }

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

@@ -1,6 +1,7 @@
 #![allow(unused_imports)]
 #![allow(clippy::too_many_arguments)]
 
+extern crate serde_repr;
 extern crate serde;
 extern crate serde_json;
 extern crate url;