Cache remapping breaks hashing of Package objects

[Julian Andres Klode]

[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), so passing autopkgtests means verification is done.

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

[Łukasz Zemczak (sil2100)]

Hello Julian, or anyone else affected,

Accepted python-apt into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/python-apt/1.6.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Julian Andres Klode (juliank)]

autopkgtest has run the tests for us, and passed for 1.6.2, so it's verified.

[Launchpad Janitor (janitor)]

This bug was fixed in the package python-apt - 1.6.2

---------------
python-apt (1.6.2) unstable; urgency=medium

  * Introduce gitlab ci
  * Document whatsnew in 1.6.y
  * Add more extensive test cases for cache remapping
  * Do not override __hash__ in apt.package.Package (LP: #1780099)
  * debian/python-apt.docs: README is README.md since some time
  * debian/control: Point to salsa instead of anonscm

 -- Julian Andres Klode <email address hidden> Mon, 09 Jul 2018 15:37:51 +0200

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for python-apt has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Julian Andres Klode (juliank)]

For unknown reasons, this bug was never marked as fix released in cosmic, but it was:

https://launchpad.net/ubuntu/+source/python-apt/1.7.0~alpha2