configure hook missing reason it was invoked

[Ondrej Kubik]

when configure hook is invoked, there are several reasons leading to it, just to mention:
 - user calling snap set <key>=<value>
 - installing snap first time
 - updating snap
 - rollback

Each of this situation requires potentially different way to be be handled. At the moment it's left down to snap configure implementation to determine this, based on some custom storing of version/revisions values and comparing them.
This is
  a) fragile as changes in snapd break it (own experience)
  b) tricky thanks to other snapd bugs (config entries not being wiped at snap remove)
  c) each snap with configure hook needs to reimplement same workaround

[Zygmunt Krynicki (zyga)]

This is a dupe of a bug reported by ogra.

[Oliver Grawert (ogra)]

and i cant find it anymore :/

[Paweł Stołowski (stolowski)]

I think the situation is slowly improving with new hooks (pre-refresh, post-refresh, install and remove hooks). Let's keep this bug open and close it when we've complete set of hooks.