Unit sell value does not account for price multipliers

[RAldrich]

Environment

• MekHQ 0.47.4
• Linux Java 8

Description

Dropship sell values are not being computed correctly, they're low by several orders of magnitude. For example: a basic Mule dropship has a MegaMekLab / buy value of ~173 million, but the sell value is only ~3 million.

This throws off all campaign finance calculations.

Looking at Unit.java, I suspect that the dropship's parts (in particular but not limited to the engines) are not being added correctly. There are several places where parts are added for SmallCraft and Jumpships, but not Dropships.

Files

[RAldrich]

Never mind my speculation about parts not getting added: Dropship extends SmallCraft (which seems like an odd design decision, but /shrug) so the conditions gating the engine parts should be returning true.

[RAldrich]

Ok did some digging, and I think the culprit is that getSellValue() doesn't take into account the x28 (spheroid) or x36 (aerodyne) cost modifier that the MegaMekLab / getBuyCost() calculations do. Accounting for that and the 0.5 used parts multiplier explains gets you pretty close (but not exactly) to the sell price.

I assume this is unintended behavior? I would expect the campaign options "used equipment" modifiers to be the only thing making the sell price lower than the buy cost.

For reference:

mule_parts_dump.txt

mule_cost_breakdown.txt

[RAldrich]

Further investigation shows that this is probably a more general issue of the sell price not accounting for price multipliers of any kind. That generally includes unit weight, but also things like Mech quirks or the premium placed on omni-units.

If all you're doing is selling units than this isn't a huge deal because you can manually edit the transaction to whatever you want. But because the sell value is the basis for most other monthly finances (including contract pay and the various upkeep cost types) it has a wider impact.