Consider cases where complexType is null (#680)

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

@@ -4423,7 +4423,11 @@ public class DefaultCodegen implements CodegenConfig {
             }
 
             if (StringUtils.isEmpty(bodyParameterName)) {
-                codegenParameter.baseName = mostInnerItem.complexType;
+                if(StringUtils.isEmpty(mostInnerItem.complexType)) {
+                    codegenParameter.baseName = "request_body";
+                } else {
+                    codegenParameter.baseName = mostInnerItem.complexType;
+                }
             } else {
                 codegenParameter.baseName = bodyParameterName;
             }

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

@@ -17,11 +17,17 @@
 
 package org.openapitools.codegen.perl;
 
-import org.testng.Assert;
-import org.testng.annotations.Test;
+import io.swagger.parser.OpenAPIParser;
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.Operation;
+import io.swagger.v3.parser.core.models.ParseOptions;
 
 import org.openapitools.codegen.CodegenConstants;
+import org.openapitools.codegen.CodegenOperation;
 import org.openapitools.codegen.languages.PerlClientCodegen;
+import org.openapitools.codegen.utils.ModelUtils;
+import org.testng.Assert;
+import org.testng.annotations.Test;
 
 public class PerlClientCodegenTest {
 
@@ -54,4 +60,14 @@ public class PerlClientCodegenTest {
         Assert.assertEquals(codegen.isHideGenerationTimestamp(), false);
     }
 
+    @Test
+    public void testIssue677() {
+        final OpenAPI openAPI = new OpenAPIParser().readLocation("src/test/resources/3_0/issue677.yaml", null, new ParseOptions()).getOpenAPI();
+        final PerlClientCodegen codegen = new PerlClientCodegen();
+
+        Operation operation = openAPI.getPaths().get("/issue677").getPost();
+        CodegenOperation co = codegen.fromOperation("/issue677", "POST", operation, ModelUtils.getSchemas(openAPI), openAPI);
+        Assert.assertNotNull(co);
+    }
+
 }

modules/openapi-generator/src/test/resources/3_0/issue677.yaml

@@ -0,0 +1,21 @@
+openapi: 3.0.1
+info:
+  title: My title
+  description: API under test
+  version: 1.0.7
+servers:
+- url: https://localhost:9999/root
+paths:
+  /issue677:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: array
+              items:
+                type: string
+      responses:
+        201:
+          description: OK
+components: {}