Update the addon to account for 12.0 ("Midnight") API changes

[rdw-software]

Since 12.0 is now available on the PTR, it is in theory feasible to start working on this (even though I don't have the time). I'll use this as a tracking issue, so that people don't have to report the individual errors resulting from API changes.

Feel free to add specific and actionable items here.

Roadmap:

• Restore basic compatibility so that the addon loads (without obvious errors)
  • Update the TOC version (and version check script - add Midnight PTR for now?)
  • Look into and resolve taint issues when accessing global Rarity
  • Replace or disable event handlers for removed events
    • COMBAT_LOG_EVENT_UNFILTERED (workaround from the alpha, not a real solution)
• Implement sanity checks/damage control mechanisms for APIs that may use "secret" values
  • Research how the system works and how to prevent it from blowing up addon code
  • Identify all uses of these APIs (and tag/highlight/isolate them?)
  • Lock down their use so that they can't throw the "secret" error (people will blame Rarity, not Blizzard)
  • WIP: Disable UNIT_DEAD (combat event processing)
  • WIP: Check which items are now impossible to track (Retail/Classic) - TBD: Add to FAQ or remove?
• Replace any APIs that were removed or saw breaking changes
  • OpenSettingsPanel (Lua error when trying to open the options UI)
• Update or conditionally disable combat event handling code that no longer works
  • Read up on the CLEU changes to see how much of the functionality will be restricted
  • WIP: Implement detection via encounter IDs (for Retail)
  • Check if it's possible to use encounters for all Classic flavors
  • Make use of proper encounter IDs wherever possible (see Discord posts)
  • Remove combat log events/globals/leftover upvalues (etc.)
  • TBD: Should track session times for encounters also? (not critical = deferred)
  • TBD: What about NPCs in dungeons? -> Impossible to track on Retail
  • TBD: What about custom items? -> Same restrictions, can't guarantee backwards compatibility
  • TBD: LibSink outputs could be affected also?
  • Look into CVar changes (floating combat text/combat log may be relevant?)
• Review use of Blizzard enums (can likely wait)
• Review use of Blizzard CVars (probably not using any relevant ones?)
• Item database updates
  • Update the difficulty settings for past expansions (maybe automate this somehow?)
  • Create a new group icon for the Midnight expansion
  • Add a new group/category for Midnight items (for the options/UI/DB)
  • Add 12.0.1 collectibles based on wowhead data
• QA/Testing (minimal as it currently is)
  • Test on the PTR or live servers
  • Make sure Classic still works in principle (ignoring the known issues :/)

Related:

• LUA Error (BETA) #929
• Running this addon with AbilityTimeline causes lua errors in AbilityTimeline #931
• Blizzard UI errors #939
• AddOn tried to call the protected function 'AceEvent30Frame:RegisterEvent() #940
• Secret string value #948
• https://www.wowace.com/projects/rarity/issues/559
• https://www.wowace.com/projects/rarity/issues/560

Pull requests:

• WoW 12.0.0 (Midnight) Compatibility #941
• Midnight update - Work In Progress  #942
• Add 12.0.1 ("Midnight") collectibles to the database #947
• Use numeric category IDs to open the Options UI #949
• Disable processing of secret unit identities #955

Resources:

• https://warcraft.wiki.gg/wiki/Patch_12.0.0/API_changes
• https://warcraft.wiki.gg/wiki/Patch_12.0.0/Planned_API_changes