[haggen]

I stumbled upon it when trying to set a default sorting for my add-on.

The bug is: 'OnHeaderClicked' is ignoring the initial direction given by ZO_SortHeader_Initialize.

Let's take a look:

File esoui\libraries\zo_sortheadergroup\zo_sortheadergroup.lua, from line 149 to 165

function ZO_SortHeaderGroup:OnHeaderClicked(header, suppressCallbacks, forceReselect)
    if self:IsEnabled() then
        local resetSortDir = false
        if forceReselect or not self:IsCurrentSelectedHeader(header) then
            self:DeselectHeader()
            resetSortDir = true
        end
 
        self.sortDirection = resetSortDir and header.initialDirection or not self.sortDirection
 
        self:SelectHeader(header)
    
        if(not suppressCallbacks) then
            self:FireCallbacks(self.HEADER_CLICKED, header.key, self.sortDirection)
        end
    end
end

Upon first calling 'OnHeaderClicked' (whether by clicking on the header or calling 'SelectHeaderByKey'), the line that sets 'sortDirection' always gets true, no matter what. I think the problem is the use of 'x and y or z', since sortDirection is a boolean flag, it's tricky to use this ternary-ish conditional instead of a full body if/else.

Edit.

Yes! As I suspected, changing the line

self.sortDirection = resetSortDir and header.initialDirection or not self.sortDirection

to

if resetSortDir then
  self.sortDirection = header.initialDirection
else
  self.sortDirection = not self.sortDirection
end

Fixed the problem!

I always found 'x and y or z' smelly, a mine waiting to be detonated. :P