Correct allOf with only one child schema (no discriminator) (#6901)

Author: wing328

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

@@ -1274,14 +1274,12 @@ public static String getParentName(ComposedSchema composedSchema, Map<String, Sc
             }
         }
 
-        // parent name only makes sense when there is a single obvious parent
-        if (refedWithoutDiscriminator.size() == 1) {
-            if (hasAmbiguousParents) {
-                LOGGER.warn("[deprecated] inheritance without use of 'discriminator.propertyName' is deprecated " +
-                                "and will be removed in a future release. Generating model for composed schema name: {}. Title: {}",
-                        composedSchema.getName(), composedSchema.getTitle());
-            }
-            return refedWithoutDiscriminator.get(0);
+        if (refedWithoutDiscriminator.size() == 1 && hasAmbiguousParents) {
+            // allOf with a single $ref (no discriminator)
+            // TODO to be removed in 5.x or 6.x release
+            LOGGER.info("[deprecated] inheritance without use of 'discriminator.propertyName' has been deprecated" +
+                    " in the 5.x release. Composed schema name: {}. Title: {}",
+                    composedSchema.getName(), composedSchema.getTitle()); 
         }
 
         return null;

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

@@ -1363,7 +1363,6 @@ public void verifyXDiscriminatorValue() {
         assertEquals(cm.discriminator, discriminator);
     }
 
-
     @Test
     public void testAllOfSingleRefNoOwnProps() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/composed-allof.yaml");
@@ -1372,9 +1371,9 @@ public void testAllOfSingleRefNoOwnProps() {
         Schema schema = openAPI.getComponents().getSchemas().get("NewMessageEventCoreNoOwnProps");
         codegen.setOpenAPI(openAPI);
         CodegenModel model = codegen.fromModel("NewMessageEventCoreNoOwnProps", schema);
-        Assert.assertEquals(getNames(model.getVars()), Collections.emptyList());
-        Assert.assertEquals(model.parent, "MessageEventCore");
-        Assert.assertEquals(model.allParents, Collections.singletonList("MessageEventCore"));
+        Assert.assertEquals(getNames(model.getVars()), Arrays.asList("id","message"));
+        Assert.assertNull(model.parent);
+        Assert.assertNull(model.allParents); 
     }
 
     class CodegenWithMultipleInheritance extends DefaultCodegen {
@@ -1385,7 +1384,6 @@ public CodegenWithMultipleInheritance() {
         }
     }
 
-
     @Test
     public void testAllOfParent() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/allOf-required-parent.yaml");

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

@@ -25,6 +25,7 @@
 import io.swagger.v3.oas.models.media.ObjectSchema;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.media.StringSchema;
+import java.util.Collections;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.CodegenModel;
 import org.openapitools.codegen.CodegenProperty;
@@ -57,8 +58,8 @@ public void javaInheritanceTest() {
 
         Assert.assertEquals(cm.name, "sample");
         Assert.assertEquals(cm.classname, "Sample");
-        Assert.assertEquals(cm.parent, "Base");
-        Assert.assertEquals(cm.imports, Sets.newHashSet("Base"));
+        Assert.assertNull(cm.parent);
+        Assert.assertEquals(cm.imports, Collections.emptySet());
     }
 
     @Test(description = "convert a composed model with discriminator")