cylinder editing

[Dirk Hohndel]

Hi there...

I have spent three hours this evening reading and debugging our code
around cylinders and editing.

It is insane and broken and terrible in more ways that I am able to
describe here. Terrible is actually way too kind.

The fundamental design how we do things is just simply wrong. For example,
when displaying a dive, we don't display the cylinders of that dive, but
we copy them into the editedDive and display those cylinders. So part of
what you see is current_dive, part is editedDive.

If we then start editing a dive, depending on whether we are adding a new
dive, planning a dive, editing a regular dive or editing a manually added
dive we do different magic things involving not one but TWO other dive
pointers, one is "current" inside the CylindersModel, the other one is
stagingDive inside the DivePlannerPointsModel. So at any point in time
there is current_dive (or master_dive), the editedDive, the stagingDive
and the "current" variable pointing to a dive. Oh, did I mention there is
another "current" variable in the WeightModel that at times is out of sync
with the one in the CylindersModel?

Add to that that the diveplanner also does magic things with cylinders and
dives. We recreate a new dive for every diveplan divepoint as we plan the
dive (Tomaz has complained about that many times). And we track the gas
consumption in the cylinders of the dive we are assembling in ways that
potentially overwrites data when we edit a manually added dive.

Are you confused, yet?

Now let's make this clear - a TON of this breakage was done by me and I am
not yelling at anyone here for bad design. I am pointing out that this
code is in frightening shape and that I'm uncomfortable doing a 4.2
release based on what's there. Bugs #553 and #582 are simply symptoms of
the mess we (I) have created...

What do people think about two weeks for fixing the outstanding bugs
including this mess and delaying 4.2 until the end of the month? I know
that several people (cough, Tomaz, cough) are itching to work on new
things for 4.3... but this would give us more time to polish the planner,
the UI, and clean up our logic and data strctures.

Thoughts, praise, disagreement?

/D