{"action":"created","issue":{"url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/17","repository_url":"https://api.github.com/repos/w3c/tt-profile-registry","labels_url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/17/labels{/name}","comments_url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/17/comments","events_url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/17/events","html_url":"https://github.com/w3c/tt-profile-registry/issues/17","id":154075755,"number":17,"title":"Registry Stability","user":{"login":"dret","id":1848612,"avatar_url":"https://avatars.githubusercontent.com/u/1848612?v=3","gravatar_id":"","url":"https://api.github.com/users/dret","html_url":"https://github.com/dret","followers_url":"https://api.github.com/users/dret/followers","following_url":"https://api.github.com/users/dret/following{/other_user}","gists_url":"https://api.github.com/users/dret/gists{/gist_id}","starred_url":"https://api.github.com/users/dret/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dret/subscriptions","organizations_url":"https://api.github.com/users/dret/orgs","repos_url":"https://api.github.com/users/dret/repos","events_url":"https://api.github.com/users/dret/events{/privacy}","received_events_url":"https://api.github.com/users/dret/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-05-10T18:33:27Z","updated_at":"2016-05-10T19:14:41Z","closed_at":null,"body":"it seems that the current policy does not make any assertions about the stability of identifiers and their meaning. this means that it is possible that identifiers get redefined by registry updates. many registries avoid this kind of semantics shift by disallowing updated, or only allowing updates that deprecate values. the reason is that typically, registry contents will be used to write code and and then any changes to entry semantics will break this code by redefining the meaning of an existing value.\r\nhttps://tools.ietf.org/html/draft-wilde-registries-01#section-3.5 makes the point that it is a common pattern to disallow updating semantics. if that isn't done, i would recommend to add a note to developers that identifier semantics may change, which probably will break implementations, even though there is little they can actually do about it."},"comment":{"url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/comments/218260667","html_url":"https://github.com/w3c/tt-profile-registry/issues/17#issuecomment-218260667","issue_url":"https://api.github.com/repos/w3c/tt-profile-registry/issues/17","id":218260667,"user":{"login":"mikedo","id":4533492,"avatar_url":"https://avatars.githubusercontent.com/u/4533492?v=3","gravatar_id":"","url":"https://api.github.com/users/mikedo","html_url":"https://github.com/mikedo","followers_url":"https://api.github.com/users/mikedo/followers","following_url":"https://api.github.com/users/mikedo/following{/other_user}","gists_url":"https://api.github.com/users/mikedo/gists{/gist_id}","starred_url":"https://api.github.com/users/mikedo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mikedo/subscriptions","organizations_url":"https://api.github.com/users/mikedo/orgs","repos_url":"https://api.github.com/users/mikedo/repos","events_url":"https://api.github.com/users/mikedo/events{/privacy}","received_events_url":"https://api.github.com/users/mikedo/received_events","type":"User","site_admin":false},"created_at":"2016-05-10T19:14:41Z","updated_at":"2016-05-10T19:14:41Z","body":"the WG provides oversight/approval to the registry changes. so, some sanity will prevail over re-using code points and similar fatal issues. as you suggest, perhaps a good practice would be never to delete a profile - at worst, deprecate it, but even that would be exceptional. I'd support forbidding the \"delete\" operation.\r\n\r\nfor updates (version management) we should recommend the assignments be stable. and the WG can do that for its own profiles. but I'm not sure the WG can dictate how 3rd parties manage the evolution of their controlling specs except via recommendations.\r\n\r\ncan you propose specific edits?"}}