Since Tags are so important in Discourse best practices, I believe we need at least the basic operations for managing them. And it seems like one that is missing is being able to merge one tag into another. For example, if users create both #dog and #dogs, at some point the admin will want to consolidate these.
What I’d expect is that when I tell it to rename #dog to #dogs it would say, “Tag already exists, do you want to merge this one in to that one?” instead of just denying the operation as it does currently.
As it stands it seems like I’d have to modify those topics one by one and finally delete the empty tag.
There is a related topic about synonyms, which is related to some degree.
The tools already exist to do this, just not in the form of a merge button. It’s actually useful to be alerted to a tag already existing, and a merger would be irreversible, so it’s probably wise that it’s not just a click away.
You can also just visit a tag page, then click on the icon to the left of Topic which reveals checkboxes to the left of each topic and the following buttons:
Hit Select All on the posts and use Append Tag on the wrench menu:
(And FWIW I wasn’t suggesting just a “one click” action. I was advocating having to click “rename tag” and then having to click through another confirmation as well. But this workaround of append and delete should be fine for me.)