Use AWS CloudFormation macros with nested stacks

You can now use AWS CloudFormation Macros directly in the Create Stack and Update Stack actions in the AWS CloudFormation Stack task to forego the previously required creation and execution of a change set and thereby enable macro usage with nested stacks. This is enabled by a new capability CAPABILITY_AUTO_EXPAND – refer to the documentation of the CreateStack API action for details:

Some templates contain macros. Macros perform custom processing on templates; this can include simple actions like find-and-replace operations, all the way to extensive transformations of entire templates. Because of this, users typically create a change set from the processed template, so that they can review the changes resulting from the macros before actually creating the stack. If your stack template contains one or more macros, and you choose to create a stack directly from the processed template, without first reviewing the resulting changes in a change set, you must acknowledge this capability. This includes the AWS::Include and AWS::Serverless transforms, which are macros hosted by AWS CloudFormation.
Change sets do not currently support nested stacks. If you want to create a stack from a stack template that contains macros and nested stacks, you must create the stack directly from the template using this capability.

Granular capabilities support

Previous releases only supported capabilities indirectly by means of the legacy Enable IAM flag, which resulted in both CAPABILITY_IAM and CAPABILITY_NAMED_IAM being enabled. In order to support the new CAPABILITY_AUTO_EXPAND and other capabilities going forward, the Enable IAM flag has now been replaced by a Capabilities configuration setting that allows an arbitrary selection of supported capabilities. Existing task configurations are still supported at task execution time and automatically converted to the new format when a task configuration is saved the next time.