[Kotlin] Correct isInherited flag for Kotlin generators (#4254)

* Correct isInherited flag for Kotlin generators

* Update Kotlin Client inheritance test to check variables

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

@@ -33,7 +33,9 @@ import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.util.*;
+import java.util.function.Function;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import static org.openapitools.codegen.utils.StringUtils.*;
 
@@ -771,7 +773,22 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
     public CodegenModel fromModel(String name, Schema schema) {
         CodegenModel m = super.fromModel(name, schema);
         m.optionalVars = m.optionalVars.stream().distinct().collect(Collectors.toList());
-        m.allVars.stream().filter(p -> !m.vars.contains(p)).forEach(p -> p.isInherited = true);
+        // Update allVars/requiredVars/optionalVars with isInherited
+        // Each of these lists contains elements that are similar, but they are all cloned
+        // via CodegenModel.removeAllDuplicatedProperty and therefore need to be updated
+        // separately.
+        // First find only the parent vars via baseName matching
+        Map<String, CodegenProperty> allVarsMap = m.allVars.stream()
+                .collect(Collectors.toMap(CodegenProperty::getBaseName, Function.identity()));
+        allVarsMap.keySet()
+                .removeAll(m.vars.stream().map(CodegenProperty::getBaseName).collect(Collectors.toSet()));
+        // Update the allVars
+        allVarsMap.values().forEach(p -> p.isInherited = true);
+        // Update any other vars (requiredVars, optionalVars)
+        Stream.of(m.requiredVars, m.optionalVars)
+                .flatMap(List::stream)
+                .filter(p -> allVarsMap.containsKey(p.baseName))
+                .forEach(p -> p.isInherited = true);
         return m;
     }
 

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

@@ -617,18 +617,6 @@ public class KotlinSpringServerCodegen extends AbstractKotlinCodegen
         }
     }
 
-    // Can't figure out the logic in DefaultCodegen but optional vars are getting duplicated when there's
-    // inheritance involved. Also, isInherited doesn't seem to be getting set properly ¯\_(ツ)_/¯
-    @Override
-    public CodegenModel fromModel(String name, Schema schema) {
-        CodegenModel m = super.fromModel(name, schema);
-
-        m.optionalVars = m.optionalVars.stream().distinct().collect(Collectors.toList());
-        m.allVars.stream().filter(p -> !m.vars.contains(p)).forEach(p -> p.isInherited = true);
-
-        return m;
-    }
-
     /**
      * Output the proper model name (capitalized).
      * In case the name belongs to the TypeSystem it won't be renamed.

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

@@ -1,12 +1,25 @@
 package org.openapitools.codegen.kotlin;
 
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.ComposedSchema;
+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 org.openapitools.codegen.CodegenConstants;
+import org.openapitools.codegen.CodegenModel;
+import org.openapitools.codegen.CodegenProperty;
 import org.openapitools.codegen.CodegenType;
+import org.openapitools.codegen.DefaultCodegen;
+import org.openapitools.codegen.TestUtils;
 import org.openapitools.codegen.languages.AbstractKotlinCodegen;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
 import java.io.File;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import static org.openapitools.codegen.CodegenConstants.ENUM_PROPERTY_NAMING_TYPE.*;
 import static org.testng.Assert.*;
@@ -197,4 +210,45 @@ public class AbstractKotlinCodegenTest {
         codegen.processOpts();
         Assert.assertFalse((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
     }
+
+    @Test
+    public void handleInheritance() {
+        Schema parent = new ObjectSchema()
+                .addProperties("a", new StringSchema())
+                .addProperties("b", new StringSchema())
+                .addRequiredItem("a")
+                .name("Parent");
+        Schema child = new ComposedSchema()
+                .addAllOfItem(new Schema().$ref("Parent"))
+                .addAllOfItem(new ObjectSchema()
+                        .addProperties("c", new StringSchema())
+                        .addProperties("d", new StringSchema())
+                        .addRequiredItem("c"))
+                .name("Child");
+        OpenAPI openAPI = TestUtils.createOpenAPI();
+        openAPI.getComponents().addSchemas(parent.getName(), parent);
+        openAPI.getComponents().addSchemas(child.getName(), child);
+
+        final DefaultCodegen codegen = new P_AbstractKotlinCodegen();
+        codegen.setOpenAPI(openAPI);
+
+        final CodegenModel pm = codegen
+                .fromModel("Child", child);
+        Map<String, CodegenProperty> allVarsMap = pm.allVars.stream()
+                .collect(Collectors.toMap(CodegenProperty::getBaseName, Function.identity()));
+        for (CodegenProperty p : pm.requiredVars) {
+            Assert.assertEquals(allVarsMap.get(p.baseName).isInherited, p.isInherited);
+        }
+        Assert.assertEqualsNoOrder(
+            pm.requiredVars.stream().map(CodegenProperty::getBaseName).toArray(),
+            new String[] {"a", "c"}
+        );
+        for (CodegenProperty p : pm.optionalVars) {
+            Assert.assertEquals(allVarsMap.get(p.baseName).isInherited, p.isInherited);
+        }
+        Assert.assertEqualsNoOrder(
+            pm.optionalVars.stream().map(CodegenProperty::getBaseName).toArray(),
+            new String[] {"b", "d"}
+        );
+    }
 }