Missing ability to list/discover extensions on object (e.g. email message)

[Googulator]

https://graph.microsoft.com/v1.0/users/{{userId}}/messages/{{messageId}}/extensions throws ErrorInvalidRequest. https://graph.microsoft.com/v1.0/users/{{userId}}/messages/{{messageId}}?$expand=extensions throws ErrorGraphExtensionExpandRequiresFilter, and the only acceptable filter seems to be of the form Id eq {{extensionId}}. (This restriction doesn't seem to be documented anywhere.)

This makes it impossible for an application to list or discover extensions on an object.

If bandwidth usage is a concern, hopefully something like https://graph.microsoft.com/v1.0/users/{{userId}}/messages/{{messageId}}/extensions?$select=Id or https://graph.microsoft.com/v1.0/users/{{userId}}/messages/{{messageId}}?$expand=extensions($select=Id) could be an acceptable solution.

[andrueastman]

Thanks for raising this @Googulator

As this repo is mainly intended for metadata related issues, any chance you can create a request at the link below to give feedback for the API owners?

https://aka.ms/graphfeedback

[Googulator]

Submitted https://feedbackportal.microsoft.com/feedback/idea/54ed3b01-3f14-ef11-989a-6045bdbb573a on the subject.