[Bug]: ScriptList::FillList does not charge scripts any opcodes

[JGRennison]

Version of OpenTTD

master

Expected result

ScriptList::FillList should charge some reasonable number of opcodes, e.g. based on the size of the pool or the number of pool items which end up in the list.

Actual result

ScriptList::FillList doesn't charge anything, even though it may consume very large amounts of CPU-time. Charging a correspondingly large number of opcodes can mitigate the performance degradation caused by scripts.

Charging a large number of opcodes may also encourage script authors to pursue more efficient methods.

Steps to reproduce

See ScriptList::FillList

[glx22]

Indeed filtering using API function is free, but using custom filter written in squirrel is not.
List constructors were free before introduction of FillList.

I agree applying filter while construction should have a cost, but I think it should be less than the Valuate cost (which is 5+call per item).

[JGRennison]

The script should be charged even if a filter isn't used.

To take a random example, AIVehicleList() iterates the whole vehicle pool and populates it with all the companies head vehicles.
ScriptList is rather slow and memory-hungry so this wastes a lot of CPU time and memory even if nothing is filtered.
It would be a perverse incentive to make unfiltered lists free but charge for filtered lists, when making ScriptList instances as small as possible (e.g. by filtering) is preferable.

[PeterN]

So basically charge by the number of results rather than the work required to produce the results.