add tests for issue #21238

modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java

@@ -1137,4 +1137,59 @@ public class KotlinSpringServerCodegenTest {
         assertFileNotContains(Paths.get(output + "/src/main/kotlin/org/openapitools/api/TestV1ApiService.kt"),
                 "Flow<kotlin.String>");
     }
+
+    @Test
+    public void testValidationsInQueryParams_issue21238_Controller() throws IOException {
+        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+        KotlinSpringServerCodegen codegen = new KotlinSpringServerCodegen();
+        codegen.setOutputDir(output.getAbsolutePath());
+
+        List<File> files = new DefaultGenerator()
+                .opts(
+                        new ClientOptInput()
+                                .openAPI(TestUtils.parseSpec("src/test/resources/3_0/kotlin/issue21238_queryParam_validation.yaml"))
+                                .config(codegen)
+                )
+                .generate();
+
+        Assertions.assertThat(files).contains(
+                new File(output, "src/main/kotlin/org/openapitools/api/PetApiController.kt"),
+                new File(output, "src/main/kotlin/org/openapitools/api/UserApiController.kt")
+        );
+
+        assertFileContains(Paths.get(output + "/src/main/kotlin/org/openapitools/api/PetApiController.kt"),
+                "@NotNull", "@Valid");
+        assertFileContains(Paths.get(output + "/src/main/kotlin/org/openapitools/api/UserApiController.kt"),
+                "@NotNull", "@Valid",
+                "@Pattern(regexp=\"^[a-zA-Z0-9]+[a-zA-Z0-9\\\\.\\\\-_]*[a-zA-Z0-9]+$\")",
+                "@Parameter(description = \"The user name for login\", required = true)",
+                "@Parameter(description = \"The password for login in clear text\", required = true)");
+    }
+
+    @Test
+    public void testValidationsInQueryParams_issue21238_Api_Delegate() throws IOException {
+        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+        KotlinSpringServerCodegen codegen = new KotlinSpringServerCodegen();
+        codegen.setOutputDir(output.getAbsolutePath());
+        codegen.additionalProperties().put(KotlinSpringServerCodegen.DELEGATE_PATTERN, true);
+
+        List<File> files = new DefaultGenerator()
+                .opts(
+                        new ClientOptInput()
+                                .openAPI(TestUtils.parseSpec("src/test/resources/3_0/kotlin/issue21238_queryParam_validation.yaml"))
+                                .config(codegen)
+                )
+                .generate();
+
+        Assertions.assertThat(files).contains(
+                new File(output, "src/main/kotlin/org/openapitools/api/PetApi.kt"),
+                new File(output, "src/main/kotlin/org/openapitools/api/UserApi.kt")
+        );
+
+        assertFileContains(Paths.get(output + "/src/main/kotlin/org/openapitools/api/PetApi.kt"),
+                "@NotNull", "@Valid");
+        assertFileContains(Paths.get(output + "/src/main/kotlin/org/openapitools/api/UserApi.kt"),
+                "@NotNull", "@Valid", "@Pattern(regexp=\"^[a-zA-Z0-9]+[a-zA-Z0-9\\\\.\\\\-_]*[a-zA-Z0-9]+$\")");
+    }
+
 }

modules/openapi-generator/src/test/resources/3_0/kotlin/issue21238_queryParam_validation.yaml

@@ -0,0 +1,61 @@
+openapi: 3.0.0
+info:
+  description: "Example to test fix for issue 21238, queryParam validation"
+  license:
+    name: Apache-2.0
+    url: https://www.apache.org/licenses/LICENSE-2.0.html
+  title: OpenAPI Query Param VAlidation
+  version: 1.0.0
+paths:
+  /pet/findByStatus:
+    get:
+      description: Multiple status values can be provided with comma separated strings
+      operationId: findPetsByStatus
+      parameters:
+      - deprecated: true
+        description: Status values that need to be considered for filter
+        explode: false
+        in: query
+        name: status
+        required: true
+        schema:
+          items:
+            default: available
+            enum:
+            - available
+            - pending
+            - sold
+            type: string
+          type: array
+        style: form
+      responses:
+        "200":
+      summary: Finds Pets by status
+      tags:
+      - pet
+  /user/login:
+    get:
+      operationId: loginUser
+      parameters:
+      - description: The user name for login
+        explode: true
+        in: query
+        name: username
+        required: true
+        schema:
+          pattern: "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$"
+          type: string
+        style: form
+      - description: The password for login in clear text
+        explode: true
+        in: query
+        name: password
+        required: true
+        schema:
+          type: string
+        style: form
+      responses:
+        "200":
+      summary: Logs user into the system
+      tags:
+      - user