[Java] Fix default values of array-type parameters in a referenced file (#17779)

* fix invalid default values of parameters with array type in a referenced file

* add test

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

@@ -1289,6 +1289,9 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             return localDate.toString();
         }
         if (ModelUtils.isArraySchema(schema)) {
+            // swagger-parser parses the default value differently depending on whether it's in a referenced file or not.
+            // cf. https://github.com/swagger-api/swagger-parser/issues/1958
+            // ArrayList if in the referenced file, ArrayNode if not.
             if (defaultValue instanceof ArrayNode) {
                 ArrayNode array = (ArrayNode) defaultValue;
                 return StreamSupport.stream(array.spliterator(), false)
@@ -1297,6 +1300,11 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                         .map(item -> StringUtils.removeStart(item, "\""))
                         .map(item -> StringUtils.removeEnd(item, "\""))
                         .collect(Collectors.joining(","));
+            } else if (defaultValue instanceof ArrayList) {
+                ArrayList<?> array = (ArrayList<?>) defaultValue;
+                return array.stream()
+                        .map(Object::toString)
+                        .collect(Collectors.joining(","));
             }
         }
         // escape quotes

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

@@ -17,14 +17,18 @@
 
 package org.openapitools.codegen.java;
 
+import io.swagger.parser.OpenAPIParser;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.media.*;
 
+import io.swagger.v3.oas.models.parameters.Parameter;
+import io.swagger.v3.parser.core.models.ParseOptions;
 import java.time.OffsetDateTime;
 import java.time.ZonedDateTime;
 import java.util.*;
 
+import java.util.stream.Collectors;
 import org.openapitools.codegen.*;
 import org.openapitools.codegen.languages.AbstractJavaCodegen;
 import org.openapitools.codegen.utils.ModelUtils;
@@ -873,6 +877,26 @@ public class AbstractJavaCodegenTest {
         Assert.assertTrue(cm.imports.contains("UUID"));
     }
 
+    @Test
+    public void arrayParameterDefaultValueDoesNotNeedBraces() throws Exception {
+        ParseOptions parseOptions = new ParseOptions();
+        parseOptions.setResolve(true);
+        final OpenAPI openAPI = new OpenAPIParser()
+                .readLocation("src/test/resources/3_0/issue_16223.yaml", null, parseOptions)
+                .getOpenAPI();
+        final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();
+        codegen.setOpenAPI(openAPI);
+
+        Map<String, Schema> schemas = openAPI.getPaths().get("/test").getGet().getParameters().stream()
+                .collect(Collectors.toMap(
+                        Parameter::getName,
+                        p -> ModelUtils.getReferencedSchema(openAPI, p.getSchema())));
+        Assert.assertEquals(codegen.toDefaultParameterValue(schemas.get("fileEnumWithDefault")), "A,B");
+        Assert.assertEquals(codegen.toDefaultParameterValue(schemas.get("fileEnumWithDefaultEmpty")), "");
+        Assert.assertEquals(codegen.toDefaultParameterValue(schemas.get("inlineEnumWithDefault")), "A,B");
+        Assert.assertEquals(codegen.toDefaultParameterValue(schemas.get("inlineEnumWithDefaultEmpty")), "");
+    }
+
     private static Schema<?> createObjectSchemaWithMinItems() {
         return new ObjectSchema()
                 .addProperties("id", new IntegerSchema().format("int32"))

modules/openapi-generator/src/test/resources/3_0/issue_16223.yaml

@@ -0,0 +1,54 @@
+---
+openapi: 3.0.3
+info:
+  title: Test
+  version: 1.0.0-SNAPSHOT
+paths:
+  /test:
+    get:
+      parameters:
+        - name: fileEnumWithDefault
+          in: query
+          schema:
+            $ref: './issue_16223_enum_with_default.yaml'
+        - name: fileEnumWithDefaultEmpty
+          in: query
+          schema:
+            $ref: './issue_16223_enum_with_default_empty.yaml'
+        - name: inlineEnumWithDefault
+          in: query
+          schema:
+            type: array
+            items:
+              type: string
+              enum:
+                - A
+                - B
+                - C
+            default:
+              - A
+              - B
+        - name: inlineEnumWithDefaultEmpty
+          in: query
+          schema:
+            type: array
+            items:
+              type: string
+              enum:
+                - A
+                - B
+                - C
+            default: []
+      responses:
+        "200":
+          description: OK
+
+components:
+  schemas:
+    Test:
+      type: object
+      properties:
+        withDefault:
+          $ref: './issue_16223_enum_with_default.yaml'
+        withEmptyDefault:
+          $ref: './issue_16223_enum_with_default_empty.yaml'

modules/openapi-generator/src/test/resources/3_0/issue_16223_enum_with_default.yaml

@@ -0,0 +1,10 @@
+type: array
+items:
+  type: string
+  enum:
+    - A
+    - B
+    - C
+default:
+  - A
+  - B

modules/openapi-generator/src/test/resources/3_0/issue_16223_enum_with_default_empty.yaml

@@ -0,0 +1,8 @@
+type: array
+items:
+  type: string
+  enum:
+    - A
+    - B
+    - C
+default: []