apt-clone does not repack debs that it will not be able to download when there isn't an Internet connection

My current thought is that we create a second apt.Cache() off /rofs (the read-only copy of the squashfs that gets copied to the target filesystem), take the set difference of installed packages from both caches, and repack each package in that delta.

Failing an adequate solution, we can hide the upgrade/reinstall option when an Internet connection is not available.

I've gotten half-way to fixing this in lp:~ev/apt-clone/766171 however it falls over when trying to restore the packages. apt-clone still tries to retrieve packages from the network, and we cannot just create a repository out of the repacked debs as they're older versions than what's present in the cache on the target system.

ev: I'm currently working on bug 766171, but I'm growing tempted to switch off the upgrade option for installs lacking an Internet connection
[11:06] cjwatson: might not be a bad idea ...
[11:07] ev: yeah, I wanted to give it my best go, as it's a really nice feature to have, but it's growing increasingly complex as I discover new facets to the bug.
[11:44] ev: okay, mpt and I talked it over and we're going to keep the option but change the text dependent on whether there's an active Internet connection (like how the prepare page works): https://docs.google.com/View?docid=0AU5sFuLRpCpBZGZra2pqY2pfMTAxZ25rcnBnNXY&hl=en#4_5_1_Automatic_partitioning_o_8475526086986065
[11:44] ev: cjwatson: do you think this is a sufficiently critical problem to warrant the late string change?
[11:44] ev: err addition
[11:45] ev: personally, I think displaying something in English is better than hiding the option and thus offering no explanation at all
[11:46] ev: (oh, and this is in the "Ubuntu {older version} on it..." box)
[12:23] cjwatson: ev: I don't see the proposed change in the Google docs link - can you point me to it specificaly?
[12:23] cjwatson: oh, I see it now
[12:23] cjwatson: ev: we should keep the "System-wide settings will be cleared" bit
[12:24] genec: Kurisutian: yes, had a connection issue but solved now
[12:24] cjwatson: (IMO)
[12:24] ev: cjwatson: agreed. mpt, are you okay with that?
[12:24] cjwatson: ev: I think at this point, I'm leaning towards preferring to disable the option for 11.04 than change the string, though
[12:25] cjwatson: I mean, if there's no network connection
[12:25] ev: cjwatson: oh? Could you elaborate on why?
[12:25] mpt: ev, done
[12:26] cjwatson: ev: because it's a new feature, and obviously this situation isn't working well; it would be better to leave people in the same state they were in for 10.10, rather than giving them an option we already know has problems
[12:26] ev: mpt: thanks
[12:28] ev: cjwatson: to clarify, do you mean disable it completely, even when there is an Internet connection?
[12:28] cjwatson: ev: no, I mean disable it only if there is no network connection
[12:28] ev: okay
[12:28] cjwatson: we already have UI that says that things may not work ideally if you don't have a connection
[12:29] ev: my concern with doing that is two people will see different results without understanding why
[12:29] ev: granted, we already have a fair bit of that on the partitioning page
[12:29] cjwatson: ev: one of those people would have had an X on the second screen already
[12:31] ev: I'm not convinced there's a clear connection between that and not having an upgrade option
[12:31] cjwatson: it's certainly not perfect, but eight days before release I'd prefer to disable a known-problematic code path rather than introduce UI to warn about its problems
[12:31] cjwatson: I'd feel differently if the upgrade option had been present in 10.10
[12:31] mpt: cjwatson, if we disable it, we will need to at least explain why, in-place, so that someone doesn't wonder why they see different options from someone else (or from the screenshot in a tutorial or book)
[12:32] mpt: and that itself would involve a new string
[12:32] mp...

eol reached https://wiki.ubuntu.com/Releases

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The Precise Pangolin has reached end of life, so this bug will not be fixed for that release