fix(stepfunctions): renderObject ignores explicit null

packages/@aws-cdk/aws-stepfunctions-tasks/lib/glue/run-glue-job-task.ts

@@ -85,7 +85,7 @@ export class RunGlueJobTask implements sfn.IStepFunctionsTask {
   }
 
   public bind(task: sfn.Task): sfn.StepFunctionsTaskConfig {
-    const notificationProperty = this.props.notifyDelayAfter ? { NotifyDelayAfter: this.props.notifyDelayAfter.toMinutes() } : null;
+    const notificationProperty = this.props.notifyDelayAfter ? { NotifyDelayAfter: this.props.notifyDelayAfter.toMinutes() } : undefined;
     let iamActions: string[] | undefined;
     if (this.integrationPattern === sfn.ServiceIntegrationPattern.FIRE_AND_FORGET) {
       iamActions = ['glue:StartJobRun'];

packages/@aws-cdk/aws-stepfunctions-tasks/lib/glue/start-job-run.ts

@@ -82,7 +82,7 @@ export class GlueStartJobRun extends sfn.TaskStateBase {
    * @internal
    */
   protected _renderTask(): any {
-    const notificationProperty = this.props.notifyDelayAfter ? { NotifyDelayAfter: this.props.notifyDelayAfter.toMinutes() } : null;
+    const notificationProperty = this.props.notifyDelayAfter ? { NotifyDelayAfter: this.props.notifyDelayAfter.toMinutes() } : undefined;
     return {
       Resource: integrationResourceArn('glue', 'startJobRun', this.integrationPattern),
       Parameters: sfn.FieldUtils.renderObject({

packages/@aws-cdk/aws-stepfunctions/lib/private/json-path.ts

@@ -40,6 +40,7 @@ export function renderObject(obj: object | undefined): object | undefined {
     handleNumber: renderNumber,
     handleBoolean: renderBoolean,
     handleResolvable: renderResolvable,
+    handleNull: renderNull,
   });
 }
 
@@ -81,6 +82,10 @@ export function findReferencedPaths(obj: object | undefined): Set<string> {
       }
       return {};
     },
+
+    handleNull(_key: string, _x: null) {
+      return {};
+    },
   });
 
   return found;
@@ -124,6 +129,7 @@ interface FieldHandlers {
   handleNumber(key: string, x: number): {[key: string]: number | string};
   handleBoolean(key: string, x: boolean): {[key: string]: boolean};
   handleResolvable(key: string, x: IResolvable): {[key: string]: any};
+  handleNull(key: string, x: null): {[key: string]: null};
 }
 
 export function recurseObject(obj: object | undefined, handlers: FieldHandlers, visited: object[] = []): object | undefined {
@@ -150,7 +156,9 @@ export function recurseObject(obj: object | undefined, handlers: FieldHandlers,
       Object.assign(ret, recurseArray(key, value, handlers, visited));
     } else if (typeof value === 'boolean') {
       Object.assign(ret, handlers.handleBoolean(key, value));
-    } else if (value === null || value === undefined) {
+    } else if (value === null) {
+      Object.assign(ret, handlers.handleNull(key, value));
+    } else if (value === undefined) {
       // Nothing
     } else if (typeof value === 'object') {
       if (Tokenization.isResolvable(value)) {
@@ -265,6 +273,13 @@ function renderBoolean(key: string, value: boolean): {[key: string]: boolean} {
   return { [key]: value };
 }
 
+/**
+ * Render a parameter null value
+ */
+function renderNull(key: string, _value: null): {[key: string]: null} {
+  return { [key]: null };
+}
+
 /**
  * If the indicated string is an encoded JSON path, return the path
  *

packages/@aws-cdk/aws-stepfunctions/test/fields.test.ts

@@ -211,6 +211,21 @@ describe('Fields', () => {
       },
     });
   });
+
+  test('null value rendered', () => {
+    const object = {
+      nullParameter: null,
+    };
+    expect(FieldUtils.renderObject(
+      {
+        reference1: object,
+      },
+    )).toStrictEqual({
+      reference1: {
+        nullParameter: null,
+      },
+    });
+  });
 });
 
 describe('intrinsics constructors', () => {