I was unable to find any related issue, so here it goes:

I'd like to request a feature to enable users (and ideally also the Azure Resource Providers) to issue warnings about upcoming changes. The idea would be that you deploy a template (for example DiagnosticSettings as a very recent example) and because of either something configured somewhere by the PG, or maybe the original creator of the template, a warning should show up in the logs during the deployment of the template.

This could look similar to how it is done in

• Terraform: source
  
• PowerShell: source

  WARNING: Set-AzureRmVMBootDiagnostics: A property of the output of this cmdlet will change in an upcoming breaking change release. The StorageAccountType property for a DataDisk will return Standard_LRS and Premium_LRS

• Azure CLI: source
  

I could see this being quite useful also for, for example, the Public Bicep Registry, or any Solution Maintainer, to notify consumers of changes ahead of time - simply by showing them custom messages in the log.

I'm aware that I'm essentially asking for 2 things here:

• Enable template creators to embedd info messages in their templates that show up during deployments
• Enable RPs to issue warnings of upcoming changes that show up during deployments

Having the first would already be great. The second then the icing on the cake - especially in response to those aformentioned changes in the backend with the diagnostic settings which all of a sudden started breaking all over the place if you didn't happen to read about the change in the docs ahead of time.