[Piuparts-devel] Bug#589498: making custom hook scripts more powerful

[Andreas Beckmann]

Hi,

currently the same hook scripts are run in several contexts but they
can't really distinguish where they are being run.
Adding a few more environment variables should help and could eventually
reduce the number of possible (and duplicate) script locations

I propose the following:

add two new environment variables
  PIUPARTS_TEST=install|upgrade|distupgrade
  PIUPARTS_PHASE=install|upgrade|distupgrade
that can be evaluated by the scripts.
PIUPARTS_TEST denotes one of the three tests
PIUPARTS_PHASE changes over time:
* install is the first installation:
  - the only one (using the packages-under-test) for TEST=install,
  - first time (using packages from the distribution) for TEST=upgrade
    and TEST=distupgrade
* upgrade is used for TEST=upgrade for the second installation
(packages-under-test) (and also for the distupgrade test where I'd like
to add something like -d NEW that finally upgrades to the
packages-under-test
* distupgrade is used for the "reinstallation" after a distupgrade in
the distupgrade test

Eventually some more environment variables may be useful:
PIUPARTS_DISTRIBUTION (always)
PIUPARTS_DISTRIBUTION_NEXT (pre_distupgrade_)
PIUPARTS_DISTRIBUTION_PREV (post_distupgrade_)

This effectively obsoletes pre/post_upgrade_ scripts.

Example trace for TEST=upgrade:

post_setup_* (already there)
record the system state that is expected to be restored afterwards
export PIUPARTS_TEST=install|upgrade|distupgrade
pre_test_* (new hook)
export PIUPARTS_PHASE=install
pre_install_*
install packages
post_install_*
export PIUPARTS_PHASE=upgrade
pre_install_*
upgrade packages
post_install_*
remove,post_remove,purge,post_purge,...
post_test_* (new hook)
check that the system state is as expected

better names for pre/post_test_* welcome - these are for global changes
that are to be reverted before the state comparision, e.g. installation
of unrelated (as in depends) but possibliy interacting packages
(diversions, alternatives, ...) that don't neccessarily fit into
post_setup_.

Also the distupgrade test (first do nothing round) needs some hook
scripts to be executed afterwards:

_post_setup_*
_pre_test_*
do
  _pre_distupgrade_*
  _post_distupgrade_*
while ...
_post_test_*
record state
restart for second round and do package installations and run
install/remove/purge scripts
compare state

With these thoughts, I'd like to put this patch on hold:
[PATCH 2/2] add more locations for hook scripts

Andreas

PS: do you have a term for the "packages under test", i.e. those passed
as .deb (or .changes) and that are the "final target" of an
installation/upgrade? (compared to their package names and predecessor
versions taken from the distribution archive)