[rust] Name a oneOf member without a title or type after its base type

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

@@ -319,8 +319,10 @@ public CodegenModel fromModel(String name, Schema model) {
                 }
                 else {
                     // In-placed type (primitive), because there is no mapping or ref for it.
-                    // use camelized `title` if present, otherwise use `type`
-                    String oneOfName = Optional.ofNullable(schema.getTitle()).orElseGet(schema::getType);
+                    // use camelized `title` if present, otherwise use `type`, otherwise the property's base type
+                    String oneOfName = Optional.ofNullable(schema.getTitle())
+                            .or(() -> Optional.ofNullable(ModelUtils.getType(schema)))
+                            .orElse(oneOf.baseType);
                     oneOf.setName(toModelName(oneOfName));
                 }
             }

modules/openapi-generator/src/test/java/org/openapitools/codegen/rust/RustClientCodegenTest.java

@@ -357,4 +357,20 @@ public void testReqwestTraitUuidParamsUseNamedLifetimes() throws IOException {
                 "async fn list_widget_items<'id, 'run_id>(&self, id: &'id str, run_id: Option<&'run_id str>)");
         TestUtils.assertFileNotContains(outputPath, "Option<&str>");
     }
+
+    @Test
+    public void testOneOfMemberWithoutTitleOrType() throws IOException {
+        Path target = Files.createTempDirectory("test");
+        target.toFile().deleteOnExit();
+        final CodegenConfigurator configurator = new CodegenConfigurator()
+                .setGeneratorName("rust")
+                .setInputSpec("src/test/resources/3_0/rust/oneof-member-without-type.yaml")
+                .setSkipOverwrite(false)
+                .setOutputDir(target.toAbsolutePath().toString().replace("\\", "/"));
+        List<File> files = new DefaultGenerator().opts(configurator.toClientOptInput()).generate();
+        files.forEach(File::deleteOnExit);
+        Path outputPath = Path.of(target.toString(), "/src/models/conditions.rs");
+        TestUtils.assertFileExists(outputPath);
+        TestUtils.assertFileContains(outputPath, "WorkflowPathCondition(Box<models::WorkflowPathCondition>)");
+    }
 }

modules/openapi-generator/src/test/resources/3_0/rust/oneof-member-without-type.yaml

@@ -0,0 +1,32 @@
+openapi: 3.0.3
+info:
+  title: oneOf member without a type
+  version: "1"
+paths:
+  /conditions:
+    get:
+      operationId: getConditions
+      responses:
+        "200":
+          description: ok
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Conditions"
+components:
+  schemas:
+    Conditions:
+      type: object
+      oneOf:
+        - type: object
+          maxProperties: 0
+        - allOf:
+            - $ref: "#/components/schemas/WorkflowPathCondition"
+          required:
+            - workflow_path
+          maxProperties: 1
+    WorkflowPathCondition:
+      type: object
+      properties:
+        workflow_path:
+          type: string