I am working on a Slack application that also communicates with a web application that users can log into using Slack. Very often, a new user will need to both log into a web application and add the application to Slack.
I would like to let them do this with one trip through OAuth. Since the web application requires a name, email address, and profile picture for each user, I added the fields "identity.basic", "identity.email", etc. For those that were requested by the "Add to Slack" button. But it turns out that Slack does not allow this. The Slack OAuth page says, " Required invalid permissions: You cannot request scopes and other scopes at the same time."
One alternative may be to request users to: read and use users: read.email areas, not identification areas. But this gives our application more access than necessary; he just needs information for the current user, and not for all users in the team. (This may be needed later for all users, so I plan to do it anyway, but I'm not sure if the users will like it.)
Another alternative seems to be to get the user to go through two different OAuth permission screens. But it seems cumbersome and not very pleasant for the user.
So the questions are: (1) is there a better way, and (2) why does Slack not allow you to combine identification areas with others?
UPDATE to clarify, in response to a response from @ erik-kalkoken:
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, "Slack app"; Slack -. - Slack .