[Java][Spring] fix reactive method with only implicit headers (#15019) (fix #14907)

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

@@ -2287,6 +2287,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 operation.allParams.add(p);
             }
         }
+        operation.hasParams = !operation.allParams.isEmpty();
     }
 
     private boolean shouldBeImplicitHeader(CodegenParameter parameter) {

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

@@ -915,6 +915,37 @@ public class SpringCodegenTest {
         assertFileNotContains(Paths.get(outputPath + "/src/main/java/org/openapitools/api/SomeApiDelegate.java"), "Mono<DummyRequest>");
     }
 
+    @Test
+    public void shouldGenerateValidCodeForReactiveControllerWithoutParams_issue14907() throws IOException {
+        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+        output.deleteOnExit();
+
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/bugs/issue_14907.yaml");
+        final SpringCodegen codegen = new SpringCodegen();
+        codegen.setOpenAPI(openAPI);
+        codegen.setOutputDir(output.getAbsolutePath());
+
+        codegen.additionalProperties().put(SpringCodegen.REACTIVE, "true");
+        codegen.additionalProperties().put(USE_TAGS, "true");
+        codegen.additionalProperties().put(SpringCodegen.DATE_LIBRARY, "java8");
+        codegen.additionalProperties().put(INTERFACE_ONLY, "true");
+        codegen.additionalProperties().put(SKIP_DEFAULT_INTERFACE, "true");
+        codegen.additionalProperties().put(IMPLICIT_HEADERS, "true");
+        codegen.additionalProperties().put(OPENAPI_NULLABLE, "false");
+
+        ClientOptInput input = new ClientOptInput();
+        input.openAPI(openAPI);
+        input.config(codegen);
+
+        DefaultGenerator generator = new DefaultGenerator();
+
+        Map<String, File> files = generator.opts(input).generate().stream()
+            .collect(Collectors.toMap(File::getName, Function.identity()));
+
+        JavaFileAssert.assertThat(files.get("ConsentControllerApi.java"))
+            .assertMethod("readAgreements", "ServerWebExchange");
+    }
+
     @Test
     public void shouldEscapeReservedKeyWordsForRequestParameters_7506_Regression() throws Exception {
         final SpringCodegen codegen = new SpringCodegen();

modules/openapi-generator/src/test/resources/bugs/issue_14907.yaml

@@ -0,0 +1,54 @@
+openapi: 3.0.1
+info:
+  title: TEST
+  description: |-
+    ## TEST
+  version: 1.0.0
+
+servers:
+  - url: /v3
+    description: Major version of service
+
+tags:
+  - name: consent-controller
+    description: Consent API
+
+
+paths:
+  /agreements:
+    parameters:
+      - $ref: '#/components/parameters/x-client-ismobile'
+    get:
+      tags:
+        - consent-controller
+      operationId: readAgreements
+      responses:
+        "200":
+          description: OK
+          content:
+            '*/*':
+              schema:
+                $ref: '#/components/schemas/ListResponseResponseAgreement'
+components:
+  schemas:
+    ResponseAgreement:
+      type: object
+      properties:
+        agreementId:
+          type: string
+    ListResponseResponseAgreement:
+      type: object
+      properties:
+        list:
+          type: array
+          items:
+            $ref: '#/components/schemas/ResponseAgreement'
+  parameters:
+    x-client-ismobile:
+      name: x-client-ismobile
+      in: header
+      description: |
+        blabla
+      schema:
+        type: boolean
+      required: false