Regression: Since commit 597bed6d22b93ed0754f3f02b632ebbcf8206596 some dependencies are not updated before reactive handlers are called

[thedac]

A regression has occurred in layer-basic, such that during a charm upgrade wheelhouse dependencies are not updated before they are called on by reactive handlers. Leading to hook errors similar to what is described in LP Bug#1875496

Steps to recreate the failure (note designate is used as an example but all reactive charms are affected):

charm pull cs:designate-38
cd designate
juju deploy ./tests/bundles/bionic_train.yaml
(wait for cloud to settle)
juju upgrade-charm --switch cs:designate-41

Per fnordahl's hint I built a new version of designate (with the charms.openstack changes) with layer-basic one commit before 597bed6 and it upgrades without error.

That seems like pretty definitive proof this is a layer-basic bug.

For future tests:
From cs:designate-38 to cs:designate-41 shows the failure.

cs:~thedac/designate-0 has layer-basic @ commit 0c8d7e2 and everything else up to date.

From cs:designate-38 to cs:~thedac/designate-0 successfully upgrades.

Logs:
Failed upgrade-charm hook upgrading to cs:designate-41 [1]
Failed upgrade-charm hook in debug-hooks session upgrading to cs:designate-41 [2]
Successful upgrade-charm hook upgrading to cs:~thedac/designate-0 [3]

Potential solution:
--quote---
cory_fu: My suspicion is that it's because the version of the library doesn't change (0.0.1-dev1) and when we were previously using filenames rather than package names, it forced it to reinstall but when we use the package name it looks at the file and thinks it's the same version and doesn't update even though we're using --ignore-installed. I think instead of --ignore-installed, we want to use --force-reinstall.
thedac: Yes, I would agree we want --force-reinstall
--end quote--

[0] https://bugs.launchpad.net/charm-aodh/+bug/1875496
[1] https://paste.ubuntu.com/p/8nHyn68tTV/
[2] http://paste.ubuntu.com/p/kX2qWTdzRR/
[3] https://pastebin.canonical.com/p/8fYYD8p4YY/