RegisterUnitEvent vs RegisterEvent - WoWInterface
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12-20-13, 12:08 AM   #1
A Firelord
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RegisterUnitEvent vs RegisterEvent

I noticed something strange today. If you use RegisterEvent("UNIT_PET") and summon a warlock demon, you get the event 4 times (the first argument is all 4 times "player"). If you use RegisterUnitEvent("UNIT_PET", "player") you only catch the 2nd and the 3rd time. Why would that be the case? A bug?
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12-20-13, 02:46 AM   #2
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I vaguely recall UNIT_PET being an annoying event in general, from back when I wrote CreatureComforts for my (long since retired now) hunter. As far as I could ever tell it fires multiple times as the pet is progressively loaded... once for "unit now exists, but everything about it is unknown", once for "okay, you can now get the pet's name and other info, but it's not fully loaded yet", and finally for "okay, now it's loaded, you can get its health and everything!" I ended up having to keep track of the state in a flag so I could ignore the irrelevant events and avoid doing a bunch of expensive processing.

Same goes for dismissing -- once for "it's despawned" and then another for "the unit no longer resolves".

You can see the effects of this even on the default unit frames. When you summon a pet, the frame appears but is grayed out, then a second later fills in with health and such. When dismissing, it goes in reverse, grays out, then disappears a second later.

I'm not sure why RegisterUnitEvent would pass through fewer events, but I'd have to say fewer events is a step in the right direction (one event would be ideal) so I wouldn't worry about it too much.
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12-20-13, 09:12 AM   #3
A Firelord
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Exactly the behavior you mention is the reason it has an implication for what I am trying to do, as the pet spells become available between the 3rd and 4th time the event fires (there is a specific SPELLS_CHANGED for that), so IsSpellKnow(id, true) just returns false if I use RegisterUnitEvent. There is an easy solution to that in my case and it was easy to spot the problem as I had some other code tracking pet spells that was functional. This just opens the question how safe is it to use RegisterUnitEvent?
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WoWInterface » Developer Discussions » Lua/XML Help » RegisterUnitEvent vs RegisterEvent

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