Hello, I think I have found an issue with the classpower element. When the max amount of charges switches for a monk's chi (done through the level 45 "Ascension" talent), the error below gets thrown.

It looks like there may be an issue with the element.__max somehow not getting set. Can someone confirm if this is working or if I am just messing stuff up?

I'm creating the element like this:

	local classPowerFrame = CreateFrame('Frame', nil, UIParent)

	local ClassPower = {}
	for i = 1, 10 do

		local Bar = CreateFrame('StatusBar', nil, self)
		Bar:SetStatusBarTexture(addon.media.texture)
		Bar:SetParent(classPowerFrame)
		Bar:SetSize(16, 6)
		Bar:SetPoint('TOPLEFT', classPowerFrame, 'TOPLEFT', (i - 1) * 17, 0)

		ClassPower[i] = Bar
	end

	self.ClassPower = ClassPower

and the error:

133x oUF\elements\classpower.lua:129: attempt to compare number with nil
[string "@oUF\elements\classpower.lua"]:129: in function <oUF\elements\classpower.lua:84>
[string "=(tail call)"]: ?
[string "@oUF\events.lua"]:81: in function <oUF\events.lua:79>
[string "=(tail call)"]: ?

Locals:
self = oUF_AelUIplayerPlayer {
 0 = <userdata>
 __tags = <table> {
 }
 UNIT_ENTERED_VEHICLE = <function> defined @oUF\ouf.lua:46
 UNIT_SPELLCAST_CHANNEL_START = <function> defined @oUF\elements\castbar.lua:314
 unitEvents = <table> {
 }
 UNIT_HEALTH_FREQUENT = <function> defined @oUF\elements\health.lua:177
 UNIT_MAXHEALTH = <function> defined @oUF\elements\health.lua:177
 __elements = <table> {
 }
 UNIT_POWER_FREQUENT = <table> {
 }
 Power = <unnamed> {
 }
 UNIT_DISPLAYPOWER = <function> defined @oUF\elements\power.lua:247
 UNIT_SPELLCAST_NOT_INTERRUPTIBLE = <function> defined @oUF\elements\castbar.lua:243
 style = "AelUI:player"
 UNIT_EXITED_VEHICLE = <function> defined @oUF\ouf.lua:46
 UNIT_CONNECTION = <table> {
 }
 UNIT_SPELLCAST_START = <function> defined @oUF\elements\castbar.lua:107
 unit = "player"
 UNIT_SPELLCAST_DELAYED = <function> defined @oUF\elements\castbar.lua:265
 UNIT_SPELLCAST_STOP = <function> defined @oUF\elements\castbar.lua:292
 UNIT_SPELLCAST_INTERRUPTED = <function> defined @oUF\elements\castbar.lua:193
 UNIT_SPELLCAST_CHANNEL_STOP = <function> defined @oUF\elements\castbar.lua:408
 UNIT_SPELLCAST_CHANNEL_UPDATE = <function> defined @oUF\elements\castbar.lua:378
 UNIT_SPELLCAST_INTERRUPTIBLE = <function> defined @oUF\elements\castbar.lua:221
 UNIT_MAXPOWER = <table> {
 }
 PLAYER_ENTERING_WORLD = <function> defined @oUF\ouf.lua:194
 UNIT_FACTION = <table> {
 }
 PLAYER_TALENT_UPDATE = <function> defined @oUF\elements\classpower.lua:209
 Health = <unnamed> {
 }
 UNIT_FLAGS = <table> {
 }
 colors = <table> {
 }
 Castbar = <unnamed> {
 }
 UNIT_POWER_BAR_SHOW = <function> defined @oUF\elements\power.lua:247
 ClassPower = <table> {
 }
 UNIT_POWER_BAR_HIDE = <function> defined @oUF\elements\power.lua:247
 UNIT_SPELLCAST_FAILED = <function> defined @oUF\elements\castbar.lua:165
}
event = "UNIT_POWER_FREQUENT"
unit = "player"
powerType = "CHI"
element = <table> {
 1 = <unnamed> {
 }
 2 = <unnamed> {
 }
 3 = <unnamed> {
 }
 4 = <unnamed> {
 }
 5 = <unnamed> {
 }
 6 = <unnamed> {
 }
 7 = <unnamed> {
 }
 8 = <unnamed> {
 }
 9 = <unnamed> {
 }
 10 = <unnamed> {
 }
}
cur = 1
max = 5
mod = 1
oldMax = nil
powerID = 12
numActive = 1.900000
(*temporary) = 5
(*temporary) = 5
(*temporary) = 1
(*temporary) = 5
(*temporary) = <function> defined =[C]:-1
(*temporary) = <unnamed> {
 0 = <userdata>
 background = <unnamed> {
 }
}
(*temporary) = 0
(*temporary) = "attempt to compare number with nil"
ClassPowerType = "CHI"
SPELL_POWER_COMBO_POINTS = 4
ClassPowerID = 12
SPEC_WARLOCK_DESTRUCTION = 3

Please let me know if I can help in debugging anything. :)

This may happen if UnitPowerMax returned nil for whatever reason. Could you test with the fix-classpower-533 branch and tell us if it fixes the issue or if it creates some undesired side-effects?

Just tried it out, but unfortunately the issue persists. I've tried doing a little bit more debugging by adding some debugging print statements around the problem code, as such:

 		oldMax = element.__max
+		print('MAX', max)
+		print('OLD MAX', oldMax)
 		if(max ~= oldMax) then
 			if(max < oldMax) then
 				for i = max + 1, oldMax do
 					element[i]:Hide()
 					element[i]:SetValue(0)
 				end
 			end
 
+			print('SET __MAX', max)
 			element.__max = max
 		end

With the "Ascension" talent selected and doing a /reload, I see the following output:

MAX 6
OLD MAX 10
SET __MAX 6

All fine, it sets the new element.__max as expected upon initialising the element.

then, switching to "Fist of the White Tiger", the following logs happen:

MAX 6
OLD MAX 6
MAX 5
OLD MAX 6
SET __MAX 5

Looks great! However, then when switching back to "Ascension":

MAX 6
OLD MAX nil
MAX 6
OLD MAX nil
MAX 6
OLD MAX nil
MAX 6
OLD MAX nil
MAX 6
OLD MAX nil

Not sure why it says this 5 times. It feels like perhaps there are multiple event handlers being attached or so? Below a screenshot of the above, with more of the output out of the chat frame, but you get the idea.

Please let me know if there's any additional debugging you'd like me to do. :)

I'll test this today - thanks for the quick fix! :)

It's my own layout I'm working on, I don't think I'm doing anything weird, but I can try to reproduce with a clean layout - maybe I'm doing something weird. I'll get back to you :)

Okay, I can't seem to reproduce this either with a new layout spawning just a player frame, so I must be messing something up in my layout... weird. I am changing parents on some of the elements though, could that be the problem?

Sorry for wasting your time!

So the issue seems to be that I'm creating some custom backgrounds for each of the power cells, and showing/hiding those myself since if I add .bg widget on each chi bar, it gets hidden. I want it to always be visible and only fill/empty based on whether that amount of chi is reached.

Is there some sane way of doing this without making a custom bg thing?

I cannot reproduce this with my layout. Can you provide a link to the layout you are using?

Tried this on the beta using my layout, cannot reproduce the issue.

Use the element's PostUpdate, check if max has changed (3rd argument, see documentation in elements/classpower.lua) and re-size and re-position your background art accordingly. Parent/attach the background art to your container frame (classPowerFrame in your example code above) not to the individual bars. You can use the .isEnabled attribute on classpower element to show/hide your background art/container frame.

Okay, that sounds a lot cleaner than what I am done now, cause I just made a frame and manually attached a UNIT_MAXPOWER event and then did stuff based on that. Thanks for the insight!

@chiel please note that depending on what the team decides, the way you are supposed to handle this might change with the next major version (which will be with Shadowlands). Please see #534 if you want to follow this discussion.

@Rainrider aye I just saw that while looking for answers to another issue I'm having, should be a very small change on my end - thanks for the heads-up!

Sorry, mistyped the issue ID, wrong reference un the last commit.

@Rainrider thanks for pinging me, I was just debugging why my classpower bars had disappeared haha. I've opted to use __isEnabled for the time being to avoid having to hook up everything else, but I'll get around that in the future.