fix null ref on invalid requestBody reference (#13199)

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

@@ -167,7 +167,7 @@ public class InlineModelResolver {
      * Return true if a model should be generated e.g. object with properties,
      * enum, oneOf, allOf, anyOf, etc.
      *
-     * @param schema target schema
+     * @param schema         target schema
      * @param visitedSchemas Visited schemas
      */
     private boolean isModelNeeded(Schema schema, Set<Schema> visitedSchemas) {
@@ -429,6 +429,10 @@ public class InlineModelResolver {
         if (requestBody.get$ref() != null) {
             String ref = ModelUtils.getSimpleRef(requestBody.get$ref());
             requestBody = openAPI.getComponents().getRequestBodies().get(ref);
+
+            if (requestBody == null) {
+                return;
+            }
         }
 
         flattenContent(requestBody.getContent(),

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

@@ -351,6 +351,19 @@ public class InlineModelResolverTest {
         assertTrue(user.getProperties().get("city") instanceof StringSchema);
     }
 
+    @Test
+    public void resolveRequestBodyInvalidRef() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
+        new InlineModelResolver().flatten(openAPI);
+
+        RequestBody requestBodyReference = openAPI
+                .getPaths()
+                .get("/resolve_request_body_invalid_ref")
+                .getPost()
+                .getRequestBody();
+        assertNull(requestBodyReference.getContent());
+    }
+
     @Test
     public void resolveInlineRequestBody() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
@@ -611,7 +624,7 @@ public class InlineModelResolverTest {
         Schema requestBodySchema = ModelUtils.getReferencedSchema(openAPI, mediaType.getSchema());
         assertNotNull(requestBodySchema);
         assertEquals(1, requestBodySchema.getProperties().size(), 1);
-        assertTrue(requestBodySchema.getProperties().get("arbitrary_object_request_body_property") instanceof  ObjectSchema);
+        assertTrue(requestBodySchema.getProperties().get("arbitrary_object_request_body_property") instanceof ObjectSchema);
     }
 
     @Test
@@ -954,12 +967,12 @@ public class InlineModelResolverTest {
                 .getContent()
                 .get("application/json")
                 .getSchema();
-                //.getProperties()
-                //.get("nullable_request_body_property");
+        //.getProperties()
+        //.get("nullable_request_body_property");
         Schema nullableRequestBodySchema = ModelUtils.getReferencedSchema(openAPI, nullableRequestBodyReference);
         //assertEquals(nullableRequestBodySchema, "");
         Schema nullableSchema = ModelUtils.getReferencedSchema(openAPI,
-                ((Schema)nullableRequestBodySchema.getProperties().get("nullable_request_body_property")));
+                ((Schema) nullableRequestBodySchema.getProperties().get("nullable_request_body_property")));
         assertTrue(nullableSchema.getNullable());
     }
 
@@ -1047,7 +1060,7 @@ public class InlineModelResolverTest {
                 requestBodyReference.getContent().get("application/json").getSchema().get$ref());
         //assertEquals("#/components/schemas/resolveInlineRequestBodyAllOf_request", requestBodyReference.get$ref());
 
-        ComposedSchema allOfModel =(ComposedSchema) openAPI.getComponents().getSchemas().get("resolveInlineRequestBodyAllOf_request");
+        ComposedSchema allOfModel = (ComposedSchema) openAPI.getComponents().getSchemas().get("resolveInlineRequestBodyAllOf_request");
         assertEquals("#/components/schemas/resolveInlineRequestBody_request", allOfModel.getAllOf().get(0).get$ref());
         //Schema allOfModel = ModelUtils.getReferencedSchema(openAPI, requestBodyReference.get$ref());
 

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

@@ -7,6 +7,14 @@ info:
 servers:
   - url: http://api.example.xyz/v1
 paths:
+  /resolve_request_body_invalid_ref:
+    post:
+      requestBody:
+        $ref: '#/components/schemas/Invalid'
+      operationId: resolveRequestBodyInvalidRef
+      responses:
+        '200':
+          description: OK
   /resolve_inline_request_body:
     post:
       requestBody:
@@ -348,6 +356,7 @@ paths:
                         data:
                           type: string
 components:
+  requestBodies: {}
   schemas:
     Users:
       type: array