selectbox_same does nothing

[AshSinc]

Description

I personally would use selectbox_same with alt autogroups and found it very useful. I notice it seems to have been broken in a recent patch. I've been away for a while so can't say which one and can't find any work on it here. Does anyone already know which commit caused the issue?

Expected Behaviour

Select some units (maybe a control group), and hold z and drag a box over an area, now it should have selected all units in that box of the same type as previously selected.

Actual Behaviour

You just get a normal box select.

Reproduction steps

No response

Other

No response

[AshSinc]

Trying to locate the cause. It seems to function normally up until around #6110 or #6112 ish. So it maybe a side effect of the changes. Will look into it a bit more.

[AshSinc]

Actually it's earlier than that. Took a bit of testing but its working ok here 31a49f7. And then breaks in the next commit here 32e1319

[AshSinc]

The problem is in gui_info.lua inside SelectionChanged(sel). When reverting this

-- Clear existing table instead of creating new one
for i = #selectedUnits, 1, -1 do
 	selectedUnits[i] = nil
end

to this :

selectedUnits = {}

it works as expected. I suppose there is some logic in unit_smart_select.lua that doesn't play well with the reused array.

[sprunk]

Excellent investigation, feel free to PR.

[AshSinc]

Trying to preserve the previous work we can instead change in unit_smart_select.lua

if mods.same and #referenceSelection > 0 then

to

if mods.same then

Which fixes the problem while keeping the more recent changes. I have a PR ready to go but I'm a little confused about why this is happening. Lua tables are referenced and then the values are being nilled. But I'm not sure how that resets the length of referenceSelection.

But if no-one can see any problem with that I'll make a PR

UPDATE

"If the first element is nil, # always returns 0". Oh ok that would go some way to explaining it