Odd delay/UI thread lockup while selling junk

[zgrssd]

I recently started getting delays when using the "sell junk" option of vendors. Usually a half second stall when selling as little as 4 items.

My theory that there is some addon that is doing work (like scanning the whole inventory) everytime a item is removed. And that this event is fired once for each item sold as junk.

I just have too many addons that could be the cause
My first guess is Inventory Insight. So I disabeled it for now and see if it continues (I had not enabeled it until recently).
Any other addons that register the respective sell/item loss event to look at? Maybe one of the research helpers (that also keeps track of what you have in your inventory)?

[zgrssd]

As far as I can tell the issue is more pronounced with Invetory Insight Running. But it is not the sole cause.

I also figured how to cheaply test it:
Just break a stack of anything with 0 worth into multiple 1 unit stacks. Mark those as junk. Finished.

It might be a dual issue:
Too many addons subscribing the event.
Each of them doing the work in the event itself.

It is best to only set a bool "data out of date" and then do the scan next UI update or some regular interval like that. That way multiple events would not cause multipel scans.

[ingeniousclown]

This should not be an issue with Research Assistant, because I have a bit of event buffering to prevent such spamminess.

[merlight]

Might be another interesting excercise Imagine an addon that hooks EVENT_MANAGER:RegisterForEvent (right away, not in it's OnLoaded handler), and reports how much time various handlers take.

local EM = GetEventManager()
local originalRegisterForEvent = EM.RegisterForEvent
local function RegisterForEventHook(self, tag, event, handler)
    if event ~= EVENT_INVENTORY_SINGLE_SLOT_UPDATE then
        -- for events we're not interested in, just call the original
        return originalRegisterForEvent(self, tag, event, handler)
    end
    local function wrapped_handler(evt, ...)
        local t1 = GetGameTimeMilliseconds()
        handler(evt, ...)
        local t2 = GetGameTimeMilliseconds()
        d(("'%s' spent %.0fms handling event %s"):format(tag, t2 - t1, evt))
    end
    return originalRegisterForEvent(self, tag, event, wrapped_handler)
end
getmetatable(EM).__index.RegisterForEvent = RegisterForEventHook

edit: fixed missing ')' and tested, it works