The main thrust of this is to not create virtual interfaces until
applying the config.
This meant that the network model has to change a bit to be able to
represent interfaces that do not yet exist on the system. I did this
by ripping out most of the existing network device code: now a
NetworkDev is really just a wrapper for the config for a device and (if
it exists) the netlink data too. A few places had to adjust to checking
if the netlink info is available before accessing it but all in all it
was not that painful.
There are a few other refactorings in this commit that perhaps should be
split out (how the bond parameters are handled, some stuff about
resizing the table rows when interfaces are edited) but it doesn't
really seem worth it.
read title and footer from the view instance, make views respsonsible for rendering
the excerpt
adapts infrastructure, welcome, keyboard, network views
Before this change, subiquity has lots of ListBoxes that just contain a single
Pile containing all their contents. This is (a) a bit silly (b) make some parts
of the scrolling experience a bit poor, for example urwid tries to scroll all
of a ListBox element into view when it gets focus but this is defeated by
shoving all the elements into a Pile (this causes
https://bugs.launchpad.net/subiquity/+bug/1750058 and a few other strange
bits).
The fix for this is obvious (don't wrap ListBox elements in a Pile) but this
breaks some aspects of tab cycling (when you shift tab back into a listbox you
want the last element of the box to be both selected and scrolled into view,
that sort of thing). Fixing all these bits of broken behaviour required
rewriting the tab cycling implementation to the point of copy/paste/hack-ing
the Pile.keypress method. Rather than doing the same for Columns, I just
prevent the creation of Columns with more than 1 selectable, which as we want
subiquity to be navigable with up/down/return does not seem so bad.
As penitence for all this, I've added a bunch of commentary explaining what is
going on.
before this, if you press up on e.g. the network view, focus would go to the first nic
not the last as you might expect. this is pretty obscure but oh well. such is urwid.