Exchange packagekit(.dart) with apt(.dart)

[Feichtmeier]

@robert-ancell @kenvandine @jpnurmi @d-loose

For once a technical, non-design discussion 😄

As you all know we currently use packagekit.dart to install, remove and update debian packages. For finding them (with images) we use appstream.dart.

Appstream.dart does a good job, it is not as fast as snapd.dart but it gets the job done.

Packagekit.dart has some problems with:

• license information
• publisher names
• update terminal output _UpdatingPage: make the detail terminal output useful #501

Packagekit.dart also has no way to make things like

• fixIncompleteInstall
• fixBrokenDepends
• upgradeSystem
• enableDistroComponent
• getTrustedVendorKeys

I've made an implementation (basically untested) of apt here https://github.com/ubuntu-flutter-community/apt.dart but before making it any better in form of tests, example and docs, what is your opinion on this?

[kenvandine]

I am certainly in favor of eliminating packagekit, which is really just a middle man in front of apt anyway. I would need to spend a little time making sure snapd provides the necessary interfaces to use this directly, which might mean a little snapd work.

It would be great to have @robert-ancell look at apt.dart and having some tests would be really useful in verifying any changes we need in snapd.

[robert-ancell]

My understanding here is:

• aptdaemon is essentially a dead project, and hasn't had any significant changes for 7 years.
• aptdaemon wasn't heavily developed, because at the time PackageKit was seen as the standard to use.
• PackageKit is also now a dead project, so now we have two zombie projects :)
• I expect that aptdaemon may not have everything we require, so it may also need work like PackageKit does. PackageKit was initially chosen as the existing store uses this so we expect the same behaviour. aptdaemon may have different behaviour or bugs.

I think the long term solution is clear, that a (standard) application store for Ubuntu should talk to a snap daemon and an apt daemon as these are the only two cases that it needs to consider. There's an open question if the apt daemon should be the current one or we should develop something more modern.

I suggest we:

• Use apt.dart in cases where PackageKit doesn't or can't provide the functionality we need (hybrid approach).
• Investigate if apt.dart can completely replace PackageKit and do the switch if we consider aptdaemon to be better maintained and more reliable than PackageKit.
• Consider long term if/how aptdaemon should be developed/maintained.

[kenvandine]

It would probably be good to check in with the foundations team for feedback on aptdaemon usage, I think Julian might have some background with aptdaemon.