[Rust-Axum][Breaking Change] Improve the oneOf model generator

bin/configs/manual/rust-axum-oneof-v3.yaml

@@ -0,0 +1,11 @@
+generatorName: rust-axum
+outputDir: samples/server/petstore/rust-axum/output/rust-axum-oneof
+inputSpec: modules/openapi-generator/src/test/resources/3_0/rust-axum/rust-axum-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/rust-axum
+generateAliasAsModel: true
+additionalProperties:
+  hideGenerationTimestamp: "true"
+  packageName: rust-axum-oneof
+globalProperties:
+  skipFormModel: "false"
+enablePostProcessFile: true

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

@@ -1083,8 +1083,8 @@ public String toString() {
         sb.append(", items='").append(items).append('\'');
         sb.append(", additionalProperties='").append(additionalProperties).append('\'');
         sb.append(", isModel='").append(isModel).append('\'');
-        sb.append(", isNull='").append(isNull);
-        sb.append(", hasValidation='").append(hasValidation);
+        sb.append(", isNull='").append(isNull).append('\'');
+        sb.append(", hasValidation='").append(hasValidation).append('\'');
         sb.append(", getAdditionalPropertiesIsAnyType=").append(getAdditionalPropertiesIsAnyType());
         sb.append(", getHasDiscriminatorWithNonEmptyMapping=").append(hasDiscriminatorWithNonEmptyMapping);
         sb.append(", getIsAnyType=").append(getIsAnyType());

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

@@ -594,8 +594,105 @@ public CodegenOperation fromOperation(String path, String httpMethod, Operation
         return op;
     }
 
+    private void postProcessOneOfModels(List<ModelMap> allModels) {
+        HashMap<String, List<String>> oneOfMapDiscriminator = new HashMap<>();
+
+        for (ModelMap mo : allModels) {
+            CodegenModel cm = mo.getModel();
+
+            CodegenComposedSchemas cs = cm.getComposedSchemas();
+            if (cs != null) {
+                List<CodegenProperty> csOneOf = cs.getOneOf();
+
+                if (csOneOf != null) {
+                    for (CodegenProperty model : csOneOf) {
+                        // Generate a valid name for the enum variant.
+                        // Mainly needed for primitive types.
+                        String[] modelParts = model.dataType.replace("<", "Of").replace(">", "").split("::");
+                        model.datatypeWithEnum = camelize(modelParts[modelParts.length - 1]);
+
+                        // Primitive type is not properly set, this overrides it to guarantee adequate model generation.
+                        if (!model.getDataType().matches(String.format(Locale.ROOT, ".*::%s", model.getDatatypeWithEnum()))) {
+                            model.isPrimitiveType = true;
+                        }
+                    }
+
+                    cs.setOneOf(csOneOf);
+                    cm.setComposedSchemas(cs);
+                }
+            }
+
+            if (cm.discriminator != null) {
+                for (String model : cm.oneOf) {
+                    List<String> discriminators = oneOfMapDiscriminator.getOrDefault(model, new ArrayList<>());
+                    discriminators.add(cm.discriminator.getPropertyName());
+                    oneOfMapDiscriminator.put(model, discriminators);
+                }
+            }
+        }
+
+        for (ModelMap mo : allModels) {
+            CodegenModel cm = mo.getModel();
+
+            for (CodegenProperty var : cm.vars) {
+                var.isDiscriminator = false;
+            }
+
+            List<String> discriminatorsForModel = oneOfMapDiscriminator.get(cm.getSchemaName());
+
+            if (discriminatorsForModel != null) {
+                for (String discriminator : discriminatorsForModel) {
+                    boolean hasDiscriminatorDefined = false;
+
+                    for (CodegenProperty var : cm.vars) {
+                        if (var.baseName.equals(discriminator)) {
+                            var.isDiscriminator = true;
+                            hasDiscriminatorDefined = true;
+                            break;
+                        }
+                    }
+
+                    // If the discriminator field is not a defined attribute in the variant structure, create it.
+                    if (!hasDiscriminatorDefined) {
+                        CodegenProperty property = new CodegenProperty();
+
+                        // Static attributes
+                        // Only strings are supported by serde for tag field types, so it's the only one we'll deal with
+                        property.openApiType = "string";
+                        property.complexType = "string";
+                        property.dataType = "String";
+                        property.datatypeWithEnum = "String";
+                        property.baseType = "string";
+                        property.required = true;
+                        property.isPrimitiveType = true;
+                        property.isString = true;
+                        property.isDiscriminator = true;
+
+                        // Attributes based on the discriminator value
+                        property.baseName = discriminator;
+                        property.name = discriminator;
+                        property.nameInCamelCase = camelize(discriminator);
+                        property.nameInPascalCase = property.nameInCamelCase.substring(0, 1).toUpperCase(Locale.ROOT) + property.nameInCamelCase.substring(1);
+                        property.nameInSnakeCase = underscore(discriminator).toUpperCase(Locale.ROOT);
+                        property.getter = String.format(Locale.ROOT, "get%s", property.nameInPascalCase);
+                        property.setter = String.format(Locale.ROOT, "set%s", property.nameInPascalCase);
+                        property.defaultValueWithParam = String.format(Locale.ROOT, " = data.%s;", property.name);
+
+                        // Attributes based on the model name
+                        property.defaultValue = String.format(Locale.ROOT, "r#\"%s\"#.to_string()", cm.getSchemaName());
+                        property.jsonSchema = String.format(Locale.ROOT, "{ \"default\":\"%s\"; \"type\":\"string\" }", cm.getSchemaName());
+
+                        cm.vars.add(property);
+                    }
+                }
+            }
+        }
+    }
+
     @Override
     public OperationsMap postProcessOperationsWithModels(final OperationsMap operationsMap, List<ModelMap> allModels) {
+        postProcessOneOfModels(allModels);
+
         final OperationMap operations = operationsMap.getOperations();
         operations.put("classnamePascalCase", camelize(operations.getClassname()));
 

modules/openapi-generator/src/main/resources/rust-axum/models.mustache

@@ -573,21 +573,70 @@ impl PartialEq for {{{classname}}} {
         self.0.get() == other.0.get()
     }
 }
+
 {{/anyOf.size}}
 {{#oneOf.size}}
-/// One of:
-{{#oneOf}}
-/// - {{{.}}}
-{{/oneOf}}
-#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
-pub struct {{{classname}}}(Box<serde_json::value::RawValue>);
+{{#discriminator}}
+#[derive(Debug, Clone, PartialEq, serde::Deserialize)]
+#[serde(tag = "{{{propertyBaseName}}}")]
+{{/discriminator}}
+{{^discriminator}}
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+#[serde(untagged)]
+{{/discriminator}}
+#[allow(non_camel_case_types)]
+pub enum {{{classname}}} {
+    {{#composedSchemas}}
+    {{#oneOf}}
+    {{{datatypeWithEnum}}}(Box<{{{dataType}}}>),
+    {{/oneOf}}
+    {{/composedSchemas}}
+}
 
 impl validator::Validate for {{{classname}}}
 {
     fn validate(&self) -> std::result::Result<(), validator::ValidationErrors> {
-        std::result::Result::Ok(())
+        match self {
+            {{#composedSchemas}}
+            {{#oneOf}}
+            {{#isPrimitiveType}}
+            Self::{{{datatypeWithEnum}}}(_) => std::result::Result::Ok(()),
+            {{/isPrimitiveType}}
+            {{^isPrimitiveType}}
+            Self::{{{datatypeWithEnum}}}(x) => x.validate(),
+            {{/isPrimitiveType}}
+            {{/oneOf}}
+            {{/composedSchemas}}
+        }
+    }
+}
+
+{{#discriminator}}
+impl serde::Serialize for {{{classname}}} {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: serde::Serializer {
+            match self {
+                {{#composedSchemas}}
+                {{#oneOf}}
+                Self::{{{datatypeWithEnum}}}(x) => x.serialize(serializer),
+                {{/oneOf}}
+                {{/composedSchemas}}
+            }
     }
 }
+{{/discriminator}}
+
+
+
+{{#composedSchemas}}
+{{#oneOf}}
+impl From<{{{dataType}}}> for {{{classname}}} {
+    fn from(value: {{{dataType}}}) -> Self {
+        Self::{{{datatypeWithEnum}}}(Box::new(value))
+    }
+}
+{{/oneOf}}
+{{/composedSchemas}}
 
 /// Converts Query Parameters representation (style=form, explode=false) to a {{{classname}}} value
 /// as specified in https://swagger.io/docs/specification/serialization/
@@ -600,11 +649,6 @@ impl std::str::FromStr for {{{classname}}} {
     }
 }
 
-impl PartialEq for {{{classname}}} {
-    fn eq(&self, other: &Self) -> bool {
-        self.0.get() == other.0.get()
-    }
-}
 {{/oneOf.size}}
 {{^anyOf.size}}
 {{^oneOf.size}}
@@ -613,11 +657,15 @@ impl PartialEq for {{{classname}}} {
 pub struct {{{classname}}} {
 {{#vars}}
 {{#description}}    
-/// {{{.}}}
+    /// {{{.}}}
 {{/description}}
 {{#isEnum}}
-/// Note: inline enums are not fully supported by openapi-generator
+    /// Note: inline enums are not fully supported by openapi-generator
 {{/isEnum}}
+{{#isDiscriminator}}
+    #[serde(default = "{{{classname}}}::__name_for_{{{name}}}")]
+    #[serde(serialize_with = "{{{classname}}}::__serialize_{{{name}}}")]
+{{/isDiscriminator}}
     #[serde(rename = "{{{baseName}}}")]
 {{#hasValidation}}
     #[validate(
@@ -685,6 +733,25 @@ pub struct {{{classname}}} {
 {{/vars}}
 }
 
+
+{{#vars}}
+{{#isDiscriminator}}
+impl {{{classname}}} {
+    fn __name_for_{{{name}}}() -> String {
+        String::from("{{{classname}}}")
+    }
+
+    fn __serialize_{{{name}}}<S>(_: &String, s: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        s.serialize_str(&Self::__name_for_{{{name}}}())
+    }
+}
+{{/isDiscriminator}}
+{{/vars}}
+
+
 {{#vars}}
 {{#hasValidation}}
 {{#pattern}}

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

@@ -0,0 +1,86 @@
+openapi: "3.0.4"
+info:
+  title: "test"
+  version: "0.0.1"
+paths:
+  "/":
+    post:
+      operationId: foo
+      requestBody:
+        required: true
+        content:
+          "application/json":
+            schema:
+              "$ref": "#/components/schemas/Message"
+      responses:
+        "200":
+          description: Re-serialize and echo the request data
+          content:
+            "application/json":
+              schema:
+                "$ref": "#/components/schemas/Message"
+components:
+  schemas:
+    Message:
+      type: object
+      additionalProperties: false
+      discriminator:
+        propertyName: op
+      oneOf:
+        - "$ref": "#/components/schemas/Hello"
+        - "$ref": "#/components/schemas/Greeting"
+        - "$ref": "#/components/schemas/Goodbye"
+      title: Message
+    Hello:
+      type: object
+      additionalProperties: false
+      title: Hello
+      properties:
+        op:
+          type: string
+          enum:
+            - Hello
+          default: Hello
+        d:
+          type: object
+          properties:
+            welcome_message:
+              type: string
+          required:
+            - welcome_message
+      required:
+        - op
+        - d
+    Greeting:
+      type: object
+      additionalProperties: false
+      title: Greeting
+      properties:
+        d:
+          type: object
+          properties:
+            greet_message:
+              type: string
+          required:
+            - greet_message
+      required:
+        - d
+    Goodbye:
+      type: object
+      additionalProperties: false
+      title: Goodbye
+      properties:
+        op:
+          type: string
+          enum:
+            - Goodbye
+        d:
+          type: object
+          properties:
+            goodbye_message:
+              type: string
+          required:
+            - goodbye_message
+      required:
+        - op
+        - d