Combatlog - Inaccurate event type for innates

[Imbafaceroll]

WoW Freakz link: Concordance of the Legionfall, Sign of the Hare; Anund's Last Breath, Lingering Insanity
Bug description: Many of the effects, generally Trinket, Legendary, Talent, Artifact trait procs are reported in combat log as UNIT_SPELLCAST_SUCCEEDED by the player. That is nonsense, instead most of these should be either SPELL_AURA_APPLIED or SPELL_AURA_APPLIED_DOSE.
Proof: https://wowwiki.fandom.com/wiki/Events/U#UNIT_SPELLCAST_SUCCEEDED

This causes nasty issues with the interface addons that sign up for these events, like reporting that spells that are cast multiple times.

For example:
Void Eruption - is correctly reported to have "UNIT_SPELLCAST_START", "UNIT_SPELLCAST_SUCCEEDED" and finally "UNIT_SPELLCAST_STOP"
Void Eruption - is incorrectly appended to the combat log as "UNIT_SPELLCAST_SUCCEEDED", right after the original cast - it makes no sense, should be some kind of damaging effect, but given that damage from the spell is already correctly reported and this type of event doesn't have a damage component, it is probably just GAZEBOS

A good rule of thumb - if the spell can't be casted by player pressing a button, it probably shouldn't trigger any of the "UNIT_SPELLCAST_" type events, especially not coming from player unit.

[Dutchbag]

Hi there!

The issues you describe are hard to identify without any context. Could you give us a few examples of spells that aren't working as they should?

I'll await further information before handling this post further. If you don't respond within a few weeks I will reject the post.

[Imbafaceroll]

The simplest example I can provide is for Lingering Insanity.
To further aid visualizing the issue you can install an addon that helps keeping track of player and enemy casted spells and global cooldowns, e.g. TrufiGCD.

Here are the basic steps to reproduce
0) Log on to Priest, change specialization to Shadow, take 1st Talent on lvl60 row
1) Gain 100 insanity through casting spells on enemy target
2) Cast Void Eruption
-- You will go into Void Form
3) Wait for insanity to drain to 0
-- Server now reports to the client that player has UNIT_SPELLCAST_SUCCEEDED with spell ID 197937
-- Take note that you never casted that spell - and by casting the game client and me refer to player actively casting an ability with that spell ID,
-- instead that is an innate (passive) ability that is not casted and should be reported in a SPELL_AURA_APPLIED or SPELL_AURA_APPLIED_DOSE (when consecutive stacks are gained)

Simply putting off and on Mangaza's Madness also causes the server to send UNIT_SPELLCAST_SUCCEEDED player, 207701

This is an issue for more spells (including passive trinket procs) than anyone can be reasonably expected to list by hand, however I believe it should be possible to query the database to retrieve exhaustive list of these spells.

[Dutchbag]

I used the command /eventtrace to check on this. The only event that happened directly after the removal of void form, was the one in the screenshot linked below.

https://imgur.com/a/we56hRM

I also looked at the code of the addon you mentioned, it seems to also track aura application. The former is likely the cause for buffs showing up in the addon's bar.

Update @ 10-04-2020, 13:58:51

I just checked the Mangaza's Madness. It does indeed trigger the event UNIT_SPELLCAST_SUCCEEDED. I don't know whether this is supposed to happen, or not. I'd need proof from retail to confirm this report, and even then it'd be a low priority report at best.

Update @ 10-04-2020, 13:59:56

Considering this issue is wider than just instanced PvE, I am moving the topic to other.

[Imbafaceroll]

Thank you for explaining, I find "/eventtrace" a very useful command indeed.
If you look for details of the events, then as I mentioned the UNIT_SPELLCAST_SUCCEEDED appears under COMBAT_LOG_EVENT_UNFILTERED
As shown here: https://i.imgur.com/4hLemS4.png

And the corresponding SPELL_AURA_APPLIED_DOSE also appears the same way,
As shown here: https://i.imgur.com/UwVPKQd.png

I believe I have found a comprehensive explanation about these events:
https://wowwiki.fandom.com/wiki/Detecting_an_instant_cast_spell

This worked correctly on Felsong during 7.1.5,
On Felsong during 7.2.5 there was a known issue with server not using SPELL_AURA_APPLIED_DOSE events at all, instead resorting to SPELL_AURA_REMOVED followed by SPELL_AURA_APPLIED with a different amount of stacks,
and it caused other unexpected side effects on the client side.

Also while using "/eventtrace" command, I noticed that, while channeling Mind Flay or Void Torrent there is a ridiculous amount of PLAYER_STARTED_MOVING immediately followed by PLAYER_STOPPED_MOVING event fired.
As shown here: https://i.imgur.com/el8CjDJ.png

I agree that this currently might have a limited impact on the player base, however I believe that correct and accurate use of combat log events is the core for a successful emulation of the "blizzlike" server and is vital for client side compatibility,
Not only compatibility with a large number of addons, but the WoW client itself.
It might be an over exaggeration, but solving this issue might even help the server stability during high loads if the server won't have to spend it's valuable resources processing and broadcasting unnecessary events to thousands of active players,
might also help alleviate client side "FPS drop" issues reported by many players on different occasions, because after all, the client just follows the instructions.