Comment 0 for bug 1780099

[Impact]
The apt.Package objects use the id as the hash, but the hash can change after reopening, meaning that code will fail to work, for example:

c=apt.Cache()
p=c["a"]
set_of_p={p}
c.open()
assert p in set_of_p

will fail.

[Test case]
The above test case is run as part of autopkgtest (syntax is slightly different)

[Regression potential]
Hashing packages objects will be slower as it hashes the name and architecture now.