diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
index e55479e4a31..8dac545365a 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
@@ -1236,7 +1236,6 @@ public class ModelUtils {
     public static List<String> getAllParentsName(ComposedSchema composedSchema, Map<String, Schema> allSchemas, boolean includeAncestors) {
         List<Schema> interfaces = getInterfaces(composedSchema);
         List<String> names = new ArrayList<String>();
-        List<String> refedWithoutDiscriminator = new ArrayList<>();
 
         if (interfaces != null && !interfaces.isEmpty()) {
             for (Schema schema : interfaces) {
@@ -1255,7 +1254,6 @@ public class ModelUtils {
                         }
                     } else {
                         // not a parent since discriminator.propertyName is not set
-                        refedWithoutDiscriminator.add(parentName);
                     }
                 } else {
                     // not a ref, doing nothing
@@ -1263,10 +1261,11 @@ public class ModelUtils {
             }
         }
 
-        if (names.size() == 0 && refedWithoutDiscriminator.size() == 1) {
-            LOGGER.warn("[deprecated] inheritance without use of 'discriminator.propertyName' is deprecated " +
-                    "and will be removed in a future release. Generating model for {}. Title: {}", composedSchema.getName(), composedSchema.getTitle());
-            return refedWithoutDiscriminator;
+        // ensure `allParents` always includes `parent`
+        // this is more robust than keeping logic in getParentName() and getAllParentsName() in sync
+        String parentName = getParentName(composedSchema, allSchemas);
+        if (parentName != null && !names.contains(parentName)) {
+            names.add(parentName);
         }
 
         return names;
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
index ead422552b7..e655027890e 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
@@ -604,6 +604,18 @@ public class DefaultCodegenTest {
         Assert.assertEquals(getRequiredVars(childModel), Collections.singletonList("name"));
     }
 
+    @Test
+    public void testAllOfSingleRefWithOwnPropsNoDiscriminator() {
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/composed-allof.yaml");
+        final DefaultCodegen codegen = new CodegenWithMultipleInheritance();
+
+        Schema schema = openAPI.getComponents().getSchemas().get("MessageEventCoreWithTimeListEntries");
+        codegen.setOpenAPI(openAPI);
+        CodegenModel model = codegen.fromModel("MessageEventCoreWithTimeListEntries", schema);
+        Assert.assertEquals(model.parent, "MessageEventCore");
+        Assert.assertEquals(model.allParents, Collections.singletonList("MessageEventCore"));
+    }
+
     @Test
     public void testAllOfSingleRefNoOwnProps() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/composed-allof.yaml");