Corner case: can a package owning a diversion disappear?

[Simon Richter <sjr@debian.org>]

Hi,

There are a few very unlikely corner cases where I'm unsure what would 
be expected of dpkg:

1. a package not providing a diverted file, and then disappearing

pkg-a contains /x and registers a diversion /y -> z.
pkg-b contains /y
pkg-c Replaces pkg-a and contains /x

Installing pkg-c overwrites the last file in pkg-a. Should pkg-a 
disappear at this point, or does the diversion count?

2. like 1, but no one else provided the diverted file either

The same scenario, but only pkg-a and pkg-c are installed, so /y does 
not even exist and is therefore not redirected to /z. Does pkg-a disappear?

3. a diversion target is replaced

pkg-a contains /x and registers a diversion /x -> y
pkg-b contains /x and is diverted to /y
pkg-c Replaces pkg-b and contains /y

Is that allowed? Does pkg-b disappear?

   Simon