refactor(callbacks): lighter EventRegistry dispatch

Modernize the frame-event forwarder: OnEvent now takes its (self, event, ...)
positionally (modern script args, on by default) and forwards straight to
TriggerEvent — dropping the DispatchGameEvent hop and the unpack(arg) repack,
and forwarding the exact arg count instead of a padded arg1..arg9 (which
silently dropped args for events that emit more than nine). A fallback reads
the event/arg globals when SetModernScriptArgs is off, so the registry stays
robust to that switch.

Keep the ordinary {[event]=count} ref-count table rather than storing counts
as frame attributes: SetAttribute is heavier per call (it lowercases the name,
runs the secure-attribute parsing, and fires OnAttributeChanged) for the same
steady-state memory, so a plain table is lighter on the register/unregister
path.

AddOns/!!!ClassicAPI/Util/GlobalCallbackRegistry.lua

@@ -1,101 +1,100 @@
 -- Backport of 3.3.5 FrameXML/GlobalCallbackRegistry.lua to vanilla 1.12 / Lua 5.0.
 --
--- Implementation differences from the 3.3.5 source:
---   - 3.3.5 ref-counts WoW frame events via a SetAttribute/OnAttributeChanged
---     dance because attribute mutations are taint-safe in the secure-template
---     model. 1.12 has neither secure templates nor SetAttribute on frames,
---     so we keep an ordinary {[event]=count} table and Register/Unregister
---     on 0<->1 transitions.
+-- Implementation notes:
+--   - 3.3.5 ref-counts frame events through a SetAttribute/OnAttributeChanged
+--     dance (attribute mutations are taint-safe under secure templates).
+--     ClassicAPI backports SetAttribute, but routing counters through it is
+--     heavier than a plain table: every set lowercases the name, runs the
+--     secure-attribute parsing, and fires OnAttributeChanged. So we keep an
+--     ordinary {[event]=count} table and Register/Unregister on 0<->1.
+--   - OnEvent takes its (self, event, ...) positionally (modern script args,
+--     on by default) and forwards straight to TriggerEvent, falling back to
+--     the event/arg globals if that switch is turned off.
 
-EventRegistry = CreateFromMixins(CallbackRegistryMixin)
+EventRegistry = CreateFromMixins(CallbackRegistryMixin);
 
 function EventRegistry:OnLoad()
-    CallbackRegistryMixin.OnLoad(self)
-    self:SetUndefinedEventsAllowed(true)
+	CallbackRegistryMixin.OnLoad(self);
+	self:SetUndefinedEventsAllowed(true);
 
-    self.eventCounts = {}
-    self.frameEventFrame = CreateFrame("Frame")
-    self.frameEventFrame.registry = self
-    self.frameEventFrame:SetScript("OnEvent", function()
-        -- 1.12 globals: `event` is the event name; `arg1..argN` are payload.
-        -- We don't repack them here; CallbackRegistryMixin:TriggerEvent uses
-        -- Lua-5.0 varargs, so we forward through a small wrapper.
-        self:DispatchGameEvent(event, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)
-    end)
+	self.eventCounts = {};
+	self.frameEventFrame = CreateFrame("Frame");
+	self.frameEventFrame:SetScript("OnEvent", function(frameEventFrame, evt, ...)
+		if evt ~= nil then
+			-- Modern positional script args (default): (self, event, payload...),
+			-- forwarded with the exact arg count.
+			self:TriggerEvent(evt, ...);
+		else
+			-- SetModernScriptArgs is off: read the event/arg globals 1.12 always
+			-- sets. This path keeps the historical 9-arg cap.
+			self:TriggerEvent(event, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9);
+		end
+	end);
 
-    -- Stop delivering events once logout begins: a callback firing during the
-    -- engine's teardown can touch state that's already gone. A dedicated frame
-    -- owns PLAYER_LOGOUT so this fires regardless of what consumers registered
-    -- — folding the check into frameEventFrame's OnEvent would depend on the
-    -- ref-counted event set still holding PLAYER_LOGOUT at logout time.
-    self.logoutFrame = CreateFrame("Frame")
-    self.logoutFrame:RegisterEvent("PLAYER_LOGOUT")
-    self.logoutFrame:SetScript("OnEvent", function()
-        self.frameEventFrame:UnregisterAllEvents()
-        self.frameEventFrame:SetScript("OnEvent", nil)
-    end)
-end
-
--- Helper so we can forward up to nine event args (the most any vanilla
--- event currently emits) into TriggerEvent's vararg machinery.
-function EventRegistry:DispatchGameEvent(event, ...)
-    self:TriggerEvent(event, unpack(arg))
+	self.logoutFrame = CreateFrame("Frame");
+	self.logoutFrame:RegisterEvent("PLAYER_LOGOUT");
+	self.logoutFrame:SetScript("OnEvent", function()
+		self.frameEventFrame:UnregisterAllEvents();
+		self.frameEventFrame:SetScript("OnEvent", nil);
+	end);
 end
 
 function EventRegistry:RegisterFrameEvent(frameEvent)
-    local n = (self.eventCounts[frameEvent] or 0) + 1
-    self.eventCounts[frameEvent] = n
-    if n == 1 then
-        self.frameEventFrame:RegisterEvent(frameEvent)
-    end
+	local n = (self.eventCounts[frameEvent] or 0) + 1;
+	self.eventCounts[frameEvent] = n;
+	if n == 1 then
+		self.frameEventFrame:RegisterEvent(frameEvent);
+	end
 end
 
 function EventRegistry:UnregisterFrameEvent(frameEvent)
-    local n = self.eventCounts[frameEvent] or 0
-    if n > 0 then
-        n = n - 1
-        self.eventCounts[frameEvent] = n
-        if n == 0 then
-            self.frameEventFrame:UnregisterEvent(frameEvent)
-        end
-    end
+	local n = self.eventCounts[frameEvent] or 0;
+	if n > 0 then
+		n = n - 1;
+		self.eventCounts[frameEvent] = n;
+		if n == 0 then
+			self.frameEventFrame:UnregisterEvent(frameEvent);
+		end
+	end
 end
 
 function EventRegistry:RegisterFrameEventAndCallback(frameEvent, ...)
-    self:RegisterFrameEvent(frameEvent)
-    return self:RegisterCallback(frameEvent, unpack(arg))
+	self:RegisterFrameEvent(frameEvent);
+	return self:RegisterCallback(frameEvent, ...);
 end
 
 local function CreateCallbackHandle(cbr, cbrHandle, frameEvent)
-    local handle = {
-        Unregister = function()
-            cbr:UnregisterFrameEvent(frameEvent)
-            cbrHandle:Unregister()
-        end,
-    }
-    return handle
+	-- Wrapped in a table for future flexibility.
+	local handle = {
+		Unregister = function()
+			cbr:UnregisterFrameEvent(frameEvent);
+			cbrHandle:Unregister();
+		end,
+	};
+	return handle;
 end
 
+
 function EventRegistry:RegisterFrameEventAndCallbackWithHandle(frameEvent, ...)
-    self:RegisterFrameEvent(frameEvent)
-    local cbrHandle = self:RegisterCallbackWithHandle(frameEvent, unpack(arg))
-    return CreateCallbackHandle(self, cbrHandle, frameEvent)
+	self:RegisterFrameEvent(frameEvent);
+	local cbrHandle = self:RegisterCallbackWithHandle(frameEvent, ...);
+	return CreateCallbackHandle(self, cbrHandle, frameEvent);
 end
 
 function EventRegistry:UnregisterFrameEventAndCallback(frameEvent, ...)
-    self:UnregisterFrameEvent(frameEvent)
-    self:UnregisterCallback(frameEvent, unpack(arg))
+	self:UnregisterFrameEvent(frameEvent);
+	self:UnregisterCallback(frameEvent, ...);
 end
 
 function EventRegistry:GetEventCounts(...)
-    local counts = {}
-    for i = 1, arg.n do
-        local frameEvent = arg[i]
-        local count = self.eventCounts[frameEvent] or "?"
-        table.insert(counts, frameEvent .. " : " .. tostring(count))
-    end
+	local counts = {};
+	for i = 1, select("#", ...) do
+		local frameEvent = select(i, ...);
+		local count = self.eventCounts[frameEvent] or "?";
+		table.insert(counts, ("%s : %s"):format(frameEvent, tostring(count)));
+	end
 
-    return table.concat(counts, "\n")
+	return table.concat(counts, "\n");
 end
 
-EventRegistry:OnLoad()
+EventRegistry:OnLoad();

README.md

@@ -22,18 +22,18 @@ The flagship feature: run modern Lua 5.1 addon code on 1.12's Lua 5.0 VM.
 | Feature | Effect |
 |---------|--------|
 | [Syntax](docs/API.md#lua-51-syntax) | Compiles the Lua 5.1 length (`#`), modulo (`%`), `...`-expression, `0x` hex-literal, and leveled long bracket (`[=[ ]=]`) syntax that vanilla's Lua 5.0 rejects, by rewriting addon source before it compiles. Each addon file also receives its `(name, table)` through `...` (`local name, tbl = ...`). |
-| [String methods](docs/API.md#string-methods-supper-sformat) | Every string value accepts method calls — `("asd"):upper()`, `("%d gold"):format(n)`, `msg:match("^!(%w+)")` — resolving through the `string` table, the way Lua 5.1 works. Vanilla's Lua 5.0 errors with `attempt to index a string value`. Works on literals and variables, in-world and on the login screen, and inside coroutines. |
-| [Script-handler arguments](docs/API.md#setmodernscriptargsenable--getmodernscriptargs) | Frame-script handlers receive their values as positional arguments — `OnMouseWheel(self, delta)`, `OnClick(self, button)`, `OnEvent(self, event, ...)`, etc. — the way 5.1+ clients do, so modern addon ports work unmodified. The `this` / `arg1` globals stay set. A handler that declares no parameters is unaffected. A handler that declared a parameter and expected nil now receives its real value. On by default. `SetModernScriptArgs(false)` restores exact vanilla dispatch. |
+| [String methods](docs/API.md#string-methods-supper-sformat) | Every string value accepts method calls — `("asd"):upper()`, `("%d gold"):format(n)`, `msg:match("^!(%w+)")` — resolving through the `string` table, the way Lua 5.1 works. Works on literals and variables, in-world and on the login screen, and inside coroutines. |
+| [Script-handler arguments](docs/API.md#setmodernscriptargsenable--getmodernscriptargs) | Frame-script handlers receive their values as positional arguments — `OnMouseWheel(self, delta)`, `OnClick(self, button)`, `OnEvent(self, event, ...)`, etc. — so modern addon ports work unmodified. The `this` / `arg1` globals stay set. A handler that declares no parameters is unaffected. A handler that declared a parameter and expected nil now receives its real value. On by default. `SetModernScriptArgs(false)` restores exact vanilla dispatch. |
 
 ### Modern client behaviors
 
 | Feature | Effect |
 |---------|--------|
-| Inline textures | Draws inline texture markup (`\|T…\|t`) as icons in FontStrings, chat, and tooltips, the way 4.3.4+ clients do. Vanilla 1.12 shows the raw escape as literal text instead. This covers item and spell icons, raid-target markers, and the coin icons in money strings. `GetStringWidth` and `GetStringHeight` count the icons, so measured width and text wrapping stay correct. Done in pure C++ by hooking the engine's text pipeline — no addon. |
+| Inline textures | Draws inline texture markup (`\|T…\|t`) as icons in FontStrings, chat, and tooltips. This covers item and spell icons, raid-target markers, and the coin icons in money strings. `GetStringWidth` and `GetStringHeight` count the icons, so measured width and text wrapping stay correct. Done in pure C++ by hooking the engine's text pipeline — no addon. |
 | Tooltip line cap | Lifts `GameTooltip`'s hard 30-line limit to 60 for every `GameTooltipTemplate` frame (`GameTooltip`, `ShoppingTooltip1/2`, `ItemRefTooltip`, AtlasLoot, …). Stat-heavy tooltips and comparison blocks (e.g. pfUI's eqcompare) no longer have their extra lines silently dropped. Done in pure C++ by growing the engine's FontString pool at tooltip-creation time. |
-| [Event-driven nameplates](docs/API.md#nameplate) | The modern `C_NamePlate` API, driven by real events instead of vanilla frame-scraping. `NAME_PLATE_UNIT_ADDED` / `NAME_PLATE_UNIT_REMOVED` fire as plates appear and vanish, `nameplate1`..`nameplateN` tokens resolve with every `UnitX` function (and fire `UNIT_HEALTH`, `UNIT_AURA`, … as `arg1 == "nameplateN"`), and `C_NamePlate.GetNamePlateForUnit` / `GetNamePlates` hand back the live frames. |
-| [Focus target](docs/API.md#focus) | A sticky focus unit, like later clients. `FocusUnit("target")` pins it and `ClearFocus()` drops it, with `PLAYER_FOCUS_CHANGED` on every change. The `focus` / `focustarget` tokens resolve with every `UnitX` function and fire unit events (`UNIT_HEALTH`, `UNIT_AURA`, … as `arg1 == "focus"`), and the predefined `FOCUSTARGET` / `TARGETFOCUS` keybinds are ready to set. |
-| [Retail-like `/reload`](docs/API.md#reload-picks-up-new-addons-and-new-files) | `/reload` picks up addon changes made while the game runs, like a modern client. A new folder under `Interface\AddOns\` registers and loads as a normal addon, new files added to an existing addon's TOC load, a newly installed addon's first SavedVariables save survives `/reload`, `##` metadata edits (`## SavedVariables:`, `## Dependencies:`, `## Title:`, …) take effect, and a deleted addon folder drops from the addon list. A stock client needs a full restart for all of these. |
+| [Event-driven nameplates](docs/API.md#nameplate) | The modern `C_NamePlate` API, driven by real events. `NAME_PLATE_UNIT_ADDED` / `NAME_PLATE_UNIT_REMOVED` fire as plates appear and vanish, `nameplate1`..`nameplateN` tokens resolve with every `UnitX` function (and fire `UNIT_HEALTH`, `UNIT_AURA`, … as `arg1 == "nameplateN"`), and `C_NamePlate.GetNamePlateForUnit` / `GetNamePlates` hand back the live frames. |
+| [Focus target](docs/API.md#focus) | A sticky focus unit. `FocusUnit("target")` pins it and `ClearFocus()` drops it, with `PLAYER_FOCUS_CHANGED` on every change. The `focus` / `focustarget` tokens resolve with every `UnitX` function and fire unit events (`UNIT_HEALTH`, `UNIT_AURA`, … as `arg1 == "focus"`), and the predefined `FOCUSTARGET` / `TARGETFOCUS` keybinds are ready to set. |
+| [Retail-like `/reload`](docs/API.md#reload-picks-up-new-addons-and-new-files) | `/reload` picks up addon changes made while the game runs. A new folder under `Interface\AddOns\` registers and loads as a normal addon, new files added to an existing addon's TOC load, a newly installed addon's first SavedVariables save survives `/reload`, `##` metadata edits (`## SavedVariables:`, `## Dependencies:`, `## Title:`, …) take effect, and a deleted addon folder drops from the addon list. |
 | [Multi-flavor & conditional TOC](docs/API.md#conditional-and-multi-flavor-toc-loading) | Loads modern multi-flavor addons that ship one folder. Selects a version-specific TOC (`<Name>_ClassicAPI.toc` or `<Name>_Turtle.toc`) and the matching keybinding file (`Bindings_ClassicAPI.xml` / `Bindings_Turtle.xml`), accepts a comma-separated `## Interface:` version list (compatible when it includes the client version `11200`), and honors per-line `[AllowLoadGameType]` / `[AllowLoadTextLocale]` conditions and `[Family]` / `[Game]` / `[TextLocale]` path variables inside a TOC. |
 
 ## Full API reference
@@ -50,7 +50,6 @@ reference in **[docs/API.md](docs/API.md)**.
 | [Action](docs/API.md#action) | `GetActionInfo` |
 | [AddOns](docs/API.md#addons) | `C_AddOns.DoesAddOnExist`, `C_AddOns.GetAddOnLocalTable`, `C_AddOns.GetAddOnName`, `C_AddOns.GetAddOnNotes`, `C_AddOns.GetAddOnOptionalDependencies`, `C_AddOns.GetAddOnSecurity`, `C_AddOns.GetAddOnTitle`, `C_AddOns.IsAddOnLoadable`, `C_AddOns.IsAddOnLoaded` |
 | [AuctionHouse](docs/API.md#auctionhouse) | `C_AuctionHouse.PostItem` |
-| [AuraUtil](docs/API.md#aurautil) | `AuraUtil.FindAura`, `AuraUtil.FindAuraByName`, `AuraUtil.ForEachAura`, `AuraUtil.UnpackAuraData` |
 | [Bindings](docs/API.md#bindings) | `SetBindingSpell`, `SetBindingItem`, `SetBindingMacro`, `SetBindingClick`, `SetOverrideBinding`, `SetOverrideBindingSpell`, `SetOverrideBindingItem`, `SetOverrideBindingMacro`, `SetOverrideBindingClick`, `ClearOverrideBindings` |
 | [Chat](docs/API.md#chat) | `GetCurrentChatGUID` |
 | [ChatBubbles](docs/API.md#chatbubbles) | `C_ChatBubbles.GetAllChatBubbles` |
@@ -68,7 +67,7 @@ reference in **[docs/API.md](docs/API.md)**.
 | [Expansion](docs/API.md#expansion) | `ClassicExpansionAtLeast`, `ClassicExpansionAtMost`, `GetClassicExpansionLevel` |
 | [Faction](docs/API.md#faction) | `C_Reputation.GetFactionDataByIndex`, `C_Reputation.GetFactionStandings`, `C_Reputation.GetLastStandingChange`, `C_Reputation.GetWatchedFactionData`, `C_Reputation.SetWatchedFactionByID`, `GetFactionIDByIndex`, `GetFactionInfoByID`, `GetFactionParentID` |
 | [Focus](docs/API.md#focus) | `ClearFocus`, `FocusUnit` |
-| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `region:IsMouseOver`, `region:GetRect`, `region:IsDragging`, `GetMouseFoci`, `frame:SetShown`, `fontstring:GetStringHeight`, `fontstring:GetUnboundedStringWidth`, `fontstring:GetWrappedWidth`, `fontstring:GetNumLines`, `fontstring:GetLineHeight`, `fontstring:IsTruncated`, `fontstring:SetMaxLines`, `fontstring:GetMaxLines`, `fontstring:SetFormattedText`, `texture:SetRotation`, `texture:GetRotation`, `texture:SetVertexOffset`, `texture:GetVertexOffset`, `texture:SetColorTexture`, `texture:SetMask`, `frame:CreateMaskTexture`, `texture:AddMaskTexture`, `texture:RemoveMaskTexture`, `texture:GetNumMaskTextures`, `texture:GetMaskTexture`, `fontstring:SetRotation`, `fontstring:GetRotation`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered`, `frame:GetEffectiveAlpha`, `frame:SetAttribute`, `frame:SetAttributeNoHandler`, `frame:ClearAttribute`, `frame:GetAttribute`, `OnAttributeChanged` (script), `SetModernScriptArgs`, `GetModernScriptArgs`, `SecureCmdOptionParse`, `RegisterStateDriver`, `UnregisterStateDriver`, `RegisterAttributeDriver`, `UnregisterAttributeDriver`, `RegisterUnitWatch`, `UnregisterUnitWatch`, `UnitWatchRegistered`, `SecureButton_GetAttribute`, `SecureButton_GetUnit`, `PreClick` (script), `PostClick` (script), `GetClickFrame` |
+| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `region:IsMouseOver`, `region:GetRect`, `region:IsDragging`, `GetMouseFoci`, `frame:SetShown`, `fontstring:GetStringHeight`, `fontstring:GetUnboundedStringWidth`, `fontstring:GetWrappedWidth`, `fontstring:GetNumLines`, `fontstring:GetLineHeight`, `fontstring:IsTruncated`, `fontstring:SetMaxLines`, `fontstring:GetMaxLines`, `fontstring:SetFormattedText`, `texture:SetRotation`, `texture:GetRotation`, `texture:SetVertexOffset`, `texture:GetVertexOffset`, `texture:SetColorTexture`, `texture:SetMask`, `frame:CreateMaskTexture`, `texture:AddMaskTexture`, `texture:RemoveMaskTexture`, `texture:GetNumMaskTextures`, `texture:GetMaskTexture`, `fontstring:SetRotation`, `fontstring:GetRotation`, `editBox:SetCursorPosition`, `editBox:GetCursorPosition`, `editBox:GetUTF8CursorPosition`, `editBox:ClearHighlightText`, `editBox:HasFocus`, `editBox:HasText`, `editBox:SetHighlightColor`, `editBox:GetHighlightColor`, `editBox:ClearHistory`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered`, `frame:GetEffectiveAlpha`, `frame:SetAttribute`, `frame:SetAttributeNoHandler`, `frame:ClearAttribute`, `frame:GetAttribute`, `OnAttributeChanged` (script), `SetModernScriptArgs`, `GetModernScriptArgs`, `PreClick` (script), `PostClick` (script), `GetClickFrame` |
 | [FriendList](docs/API.md#friendlist) | `C_FriendList.GetFriendInfo`, `C_FriendList.GetFriendInfoByIndex`, `C_FriendList.GetNumFriends`, `C_FriendList.GetNumOnlineFriends`, `C_FriendList.GetNumWhoResults`, `C_FriendList.GetWhoInfo`, `C_FriendList.IsFriend`, `C_FriendList.IsIgnored`, `C_FriendList.IsIgnoredByGuid`, `C_FriendList.IsWhoQueryPending`, `C_FriendList.SendWhoQueryByName`, `C_FriendList.SetFriendNotes`, `C_FriendList.SetFriendNotesByIndex` |
 | [GameObject](docs/API.md#gameobject) | `C_GameObjectInfo.GetGameObjectInfoByID`, `C_GameObjectInfo.RequestLoadGameObjectByID`, `ClosestGameObjectPosition` |
 | [Glue](docs/API.md#glue) | `C_Glue.IsOnGlueScreen` |
@@ -117,9 +116,7 @@ reference in **[docs/API.md](docs/API.md)**.
 Registered on the **glue** Lua state (the engine that runs the login,
 realm-select, and character-select screens). The persistence entries
 in the first row are *glue-only* — they exist to support GlueXML
-patches that need a small persistence surface across sessions, since
-vanilla 1.12 glue ships no general-purpose persistence API beyond
-`GetSavedAccountName`/`SetSavedAccountName` (saturated by autologin).
+patches that need a small persistence surface across sessions.
 The rest of the table is in-game calls that we also mirror onto
 the glue state because GlueXML had no way to reach them otherwise.
 
@@ -138,7 +135,7 @@ the glue state because GlueXML had no way to reach them otherwise.
 <summary><b>Macros</b> — engine-level parsing extensions</summary>
 
 Engine-level extensions to macro parsing and dispatch — no new Lua
-functions, just behavior the stock 1.12 engine didn't have. See the
+functions. See the
 [Macros section in the Lua reference](docs/API.md#macros) for details.
 
 | Form | What it does |
@@ -228,7 +225,7 @@ when launching with `-console`), not as Lua functions. See the
 
 | Group | Constants |
 |-------|-----------|
-| Version | `CLASSIC_API_VERSION` |
+| Version | `CLASSIC_API_VERSION`, `INTERFACE_VERSION` |
 | Expansion | `LE_EXPANSION_LEVEL_CURRENT`, `LE_EXPANSION_CLASSIC` … `LE_EXPANSION_MIDNIGHT` |
 | Item quality | `LE_ITEM_QUALITY_POOR` … `LE_ITEM_QUALITY_WOWTOKEN` |
 | Unit stat | `LE_UNIT_STAT_STRENGTH` … `LE_UNIT_STAT_SPIRIT` |
@@ -256,7 +253,7 @@ when launching with `-console`), not as Lua functions. See the
 <details>
 <summary><b>Bindings</b> — direct-action and override binding families</summary>
 
-ClassicAPI backports the later-client direct-action and temporary override
+ClassicAPI backports the direct-action and temporary override
 binding families. Permanent bindings use the standard `SPELL`, `ITEM`,
 `MACRO`, and `CLICK` command strings and can be saved normally. Overrides are
 session-only, frame-owned, and support the usual priority flag.
@@ -337,7 +334,7 @@ identically in both cases.
 ## Bundled addon: DebugTools
 
 A 1.12.1 / Lua 5.0 backport of Blizzard's `Blizzard_DebugTools` addon
-(originally shipped with the 3.0 client) lives in [`AddOns/DebugTools/`](AddOns/DebugTools/).
+lives in [`AddOns/DebugTools/`](AddOns/DebugTools/).
 It's an independent addon — it doesn't use anything ClassicAPI adds, and
 ClassicAPI works fine without it. It's bundled here because it's the
 natural companion for testing and debugging anything written against the
@@ -352,12 +349,11 @@ Slash commands provided:
 | `/framestack` (or `/fstack`) | Tooltip showing the frame hierarchy under the mouse cursor. |
 | `/luaerrors` (or `/scripterrors`) | Lua error display window. |
 
-Lua globals provided (backports of 3.3.5 helpers that don't exist in
-1.12):
+Lua globals provided (backports of Blizzard helpers):
 
 | Global | Purpose |
 |--------|---------|
-| `print(...)` | Backport of the 3.3.5 `print` — concats varargs with `" "` and pushes to `DEFAULT_CHAT_FRAME`. Routes through `setprinthandler`'s handler; falls back via `geterrorhandler` if the handler errors. |
+| `print(...)` | Backport of Blizzard's `print` — concats varargs with `" "` and pushes to `DEFAULT_CHAT_FRAME`. Routes through `setprinthandler`'s handler; falls back via `geterrorhandler` if the handler errors. |
 | `setprinthandler(func)` / `getprinthandler()` | Install / query a custom print handler. Useful for redirecting print output in tests. |
 | `tostringall(...)` | Apply `tostring()` to every vararg, preserving the count. Lua 5.0-compatible (uses `arg.n` since `select` doesn't exist in 5.0). |
 

src/Game.cpp

@@ -46,6 +46,7 @@ namespace Lua {
     F(RawGet,      lua_rawget,      LUA_RAW_GET)      \
     F(SetTable,    lua_settable,    LUA_SET_TABLE)    \
     F(RawSet,      lua_rawset,      LUA_RAW_SET)      \
+    F(SetMetatable,lua_setmetatable,LUA_SET_METATABLE)\
     F(Insert,      lua_insert,      LUA_INSERT)       \
     F(Remove,      lua_remove,      LUA_REMOVE)       \
     F(GetTop,      lua_gettop,      LUA_GET_TOP)      \

src/Game.h

@@ -123,6 +123,9 @@ using lua_gettable_t = void(__fastcall *)(void *L, int idx);
 using lua_rawget_t = void(__fastcall *)(void *L, int idx);
 using lua_settable_t = void(__fastcall *)(void *L, int idx);
 using lua_rawset_t = void(__fastcall *)(void *L, int idx);
+// Pops the table at the top and installs it as the metatable of the value
+// at idx; returns 1.
+using lua_setmetatable_t = int(__fastcall *)(void *L, int idx);
 using lua_insert_t = void(__fastcall *)(void *L, int idx);
 using lua_remove_t = void(__fastcall *)(void *L, int idx);
 using lua_gettop_t = int(__fastcall *)(void *L);
@@ -178,6 +181,7 @@ extern const lua_gettable_t GetTable;
 extern const lua_rawget_t RawGet;
 extern const lua_settable_t SetTable;
 extern const lua_rawset_t RawSet;
+extern const lua_setmetatable_t SetMetatable;
 extern const lua_insert_t Insert;
 extern const lua_remove_t Remove;
 extern const lua_gettop_t GetTop;

src/Offsets.h

@@ -299,7 +299,12 @@ enum Offsets {
     // the pointer at +0xB8 (both verified from the setters below). We read a
     // line's text/color and re-apply them one slot down, then set line 0.
     FUN_FONTSTRING_SET_TEXT = 0x00771D80,         // __thiscall(fs, text, flag=0)
-    FUN_FONTSTRING_SET_COLOR = 0x0077F750,        // __thiscall(fs, colorBGRA*)
+    FUN_FONTSTRING_SET_COLOR = 0x0077F750,        // __thiscall(region, colorBGRA*) — generic region color setter (fontstrings + textures)
+    // Generic region color GETTER — `void __thiscall(region, uint32* outBGRA)`,
+    // writes the packed {b,g,r,a} (0xFFFFFFFF when the region has no explicit
+    // color). The read half of Texture:GetVertexColor (FUN_0079aa50); paired
+    // with FUN_FONTSTRING_SET_COLOR above. Backs EditBox:GetHighlightColor.
+    FUN_REGION_GET_COLOR = 0x0077F8C0,
     OFF_FONTSTRING_TEXT = 0xF0,                   // char* — current text buffer
     OFF_FONTSTRING_COLOR_PTR = 0xB8,              // ptr → 4-byte {b,g,r,a} color storage
     // A line's FontString is only positioned once shown: set the desired
@@ -1901,6 +1906,11 @@ enum Offsets {
     VAR_FRAME_METHOD_REGISTRY = 0x00CF4D38,
     VAR_TEXTURE_METHOD_REGISTRY = 0x00CF5434,
     VAR_FONTSTRING_METHOD_REGISTRY = 0x00CF5400,
+    // EditBox — 48 methods (table 0x0087BB68), ctx per
+    // docs/BlizzardScriptAPI.md. Backs `EditBox:SetCursorPosition` /
+    // `GetCursorPosition` (`EditBox::Methods`), the modern cursor / focus /
+    // text-state methods vanilla's EditBox lacks.
+    VAR_EDITBOX_METHOD_REGISTRY = 0x00CF5378,
 
     // Model frame — backs `Model:SetDisplayInfo(creatureDisplayID)`
     // (`Model::DisplayInfo`). Registry ctx per docs/raw_methods.txt (table
@@ -4866,6 +4876,11 @@ enum Offsets {
     // Verified in docs/LuaCAPI.md and by the getfenv/getmetatable base-lib
     // functions that call it. Used by the `__environment` env-protection hook.
     LUA_GET_METATABLE = 0x6F3CF0,
+    // `lua_setmetatable(L, objindex)` — pops the table at the top of the
+    // stack and installs it as the metatable of the value at objindex;
+    // returns 1. Catalogued (★-verified) in docs/LuaCAPI.md. Used by
+    // Table::Length to build its weak-keyed mark table from C.
+    LUA_SET_METATABLE = 0x6F4020,
     // `lua_getfenv(L, idx)` — pushes the environment table of the function
     // (or userdata/thread) at `idx`. The getfenv/setfenv base-lib code calls
     // it to read a function's environment before the protection check.
@@ -4945,6 +4960,16 @@ enum Offsets {
     // (named there since the table.insert trace). Used by the 5.1
     // `unpack(list, i, j)` upgrade for the default range end.
     LUAL_GETN = 0x6F5050,
+    // `table.insert` (5.0 `luaB_tinsert`), `int __fastcall(L)`. Found two
+    // independent ways: the table-lib luaL_reg pair in .data (entry
+    // {name 0x008821B4 "insert", func} at 0x00822D70) and the LUAL_SETN
+    // caller trace above. Decompile matches 5.0.2 tinsert exactly:
+    // lua_gettop → luaL_checktype(1, TABLE) → n = luaL_getn(1)+1 →
+    // optional-pos shift-up loop (rawgeti/rawseti) → luaL_setn(1, n) →
+    // lua_pushvalue(value) → lua_rawseti(1, pos). Both `table.insert` and
+    // the FrameXML `tinsert` alias resolve to this one C function. Hooked
+    // by Table::Length to mark deliberate trailing-nil appends (#36/#39).
+    FUN_LUA_TABLE_INSERT = 0x7FB6B0,
     // `luaV_gettable(L, t, key, loop)` — the VM's generic index resolver.
     // __fastcall(L /*ecx*/, t /*edx*/, key /*stack*/, loop /*stack*/),
     // RET 8. Returns the result TValue* in eax (Ghidra types it void; the
@@ -7559,6 +7584,55 @@ enum Offsets {
     // *(this+0xF0) via SStrDup.
     OFF_EDITBOX_TEXT_FONTSTRING = 0x328, // CSimpleFontString* — the display text object
 
+    // CSimpleEditBox cursor / selection internals (backs EditBox::Methods'
+    // SetCursorPosition / GetCursorPosition). Verified from the engine's own
+    // HighlightText (FUN_00798870 → FUN_0077cca0) and Insert (FUN_00798400 →
+    // FUN_0077bee0) paths:
+    //   +0x31c dirty-flag dword — bit 2 = selection/highlight changed, bit 4 =
+    //          cursor changed (both trigger the next-paint relayout).
+    //   +0x338 text length in BYTES (the clamp bound below).
+    //   +0x35c / +0x360 selection start / end (byte offsets).
+    //   +0x36c cursor insertion point, a BYTE offset — matches modern WoW's
+    //          byte-based EditBox cursor (GetCursorPosition returns bytes; for
+    //          ASCII text byte == character).
+    OFF_EDITBOX_FLAGS = 0x31c,
+    OFF_EDITBOX_TEXT_LENGTH = 0x338,   // current text length in bytes
+    OFF_EDITBOX_CURSOR_BYTE = 0x36c,
+    // `void __thiscall(editbox, byteOffset)` — sets the cursor to a byte
+    // offset, clamping to [0, textByteLen] and OR-ing the +0x31c cursor-dirty
+    // bit. The engine's own "restore cursor" primitive (called from the insert
+    // path FUN_0077bee0 to put the caret back after splicing text).
+    FUN_EDITBOX_SET_CURSOR_BYTE = 0x0077e360,
+    // `void __thiscall(editbox)` — collapses the selection onto the cursor
+    // (selStart = selEnd = +0x36c). The engine's own "clear selection to the
+    // caret" helper (FUN_0077ccf0), used before extending a shift-selection.
+    FUN_EDITBOX_COLLAPSE_SELECTION = 0x0077ccf0,
+    // `int __thiscall(editbox, startByteIndex, byteCount)` — counts CHARACTERS
+    // (UTF-8 codepoints) in a byte range, walking the per-byte char-class table
+    // at +0x330 (a byte begins a codepoint when its class is 2/3/6). So
+    // `COUNT_CHARS(eb, 0, cursorByteOffset)` is the cursor's character index —
+    // backs GetUTF8CursorPosition. Verified from the arrow-key mover
+    // FUN_0077cb20's own `FUN_0077bc80(this, byteOff, cursorByte - byteOff)`.
+    FUN_EDITBOX_COUNT_CHARS = 0x0077bc80,
+    // Selection-highlight regions — three consecutive CSimpleTexture pointers
+    // (start-line +0x350, middle-block +0x354, end-line +0x358) the editbox
+    // shows/positions to paint the selection (FUN_0077d950). Their vertex
+    // color IS the highlight color — Set/GetHighlightColor read/write it via
+    // the generic region color accessors. The blinking caret is a SEPARATE
+    // region at +0x3d4, deliberately left alone.
+    OFF_EDITBOX_HIGHLIGHT_REGION = 0x350,
+    // Input-history ring buffer: max lines (ring capacity) at +0x388 (what
+    // GetHistoryLines reads), write position at +0x38c, container
+    // {size@+0x390, alloc@+0x394, data@+0x398} of {char* text, int exec}
+    // entries. AddHistoryLine writes at +0x38c and advances modulo +0x388.
+    OFF_EDITBOX_HISTORY_MAX = 0x388,
+    // `void __thiscall(editbox, int maxLines)` — the SetHistoryLines internal
+    // (FUN_0077cd90). Reallocates the history ring to maxLines; maxLines == 0
+    // frees the whole buffer and zeroes the container. ClearHistory calls it
+    // with 0 then the saved max — empties every entry and resets the write
+    // position while keeping the limit (so recording still works after).
+    FUN_EDITBOX_SET_HISTORY_MAX = 0x0077cd90,
+
     // --- FontString measure internals (GetStringWidth icon fix + GetStringHeight) ---
     // CSimpleFontString::GetStringWidthInternal — `float(__fastcall)(fs /*ecx*/)`,
     // returns in x87 ST0. Lazily computes into the fs+0xFC cache (ANCHOR units,

src/editbox/Methods.cpp

@@ -0,0 +1,246 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// Modern EditBox method backports — cursor, selection, focus and text-state
+// accessors that vanilla's 48-method EditBox registry lacks but modern addons
+// call unconditionally (the caret bug that motivated this: TwitchEmotes'
+// autocomplete calls SetCursorPosition after replacing the text).
+//
+//   SetCursorPosition / GetCursorPosition   — caret as a byte offset
+//   GetUTF8CursorPosition                   — caret as a character index
+//   ClearHighlightText                      — drop the selection, keep the caret
+//   HasFocus                                — does this box own keyboard focus
+//   HasText                                 — is the box non-empty
+//   Set/GetHighlightColor                   — the text-selection highlight color
+//   ClearHistory                            — empty the up/down input history
+//
+// The engine already stores and manipulates all of this; we just expose it.
+// Every method is registered on the EditBox method registry, so — like any
+// per-type frame method — only EditBox frames dispatch to them (a Button or
+// Frame still gets "method not found"), so the resolved `this` is always a
+// real CSimpleEditBox.
+//
+// The caret is a BYTE offset into the UTF-8 text buffer (field +0x36c), which
+// is exactly what modern WoW's byte-based EditBox cursor uses — for ASCII text
+// a byte offset equals a character index, so callers passing `#text` land at
+// the end either way.
+
+#include "Game.h"
+#include "Offsets.h"
+
+#include <cstdint>
+
+namespace EditBox::Methods {
+
+namespace {
+
+using SetCursorByte_t = void(__thiscall *)(void *editbox, int byteOffset);
+using CollapseSelection_t = void(__thiscall *)(void *editbox);
+using CountChars_t = int(__thiscall *)(void *editbox, int startByte, int byteCount);
+using RegionSetColor_t = void(__thiscall *)(void *region, const uint32_t *colorBGRA);
+using RegionGetColor_t = void(__thiscall *)(void *region, uint32_t *outBGRA);
+using SetHistoryMax_t = void(__thiscall *)(void *editbox, int maxLines);
+
+// A Lua color arg (0..1) clamped and scaled to a 0..255 byte, matching the
+// engine's own float->byte color conversion (truncating, like Texture's
+// SetVertexColor). `dflt` is used when the arg is absent.
+uint32_t ColorByte(void *L, int idx, double dflt) {
+    double v = Game::Lua::IsNumber(L, idx) ? Game::Lua::ToNumber(L, idx) : dflt;
+    if (v < 0.0)
+        v = 0.0;
+    else if (v > 1.0)
+        v = 1.0;
+    return static_cast<uint32_t>(v * 255.0);
+}
+
+int __fastcall Script_SetCursorPosition(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr || !Game::Lua::IsNumber(L, 2)) {
+        Game::Lua::Error(L, "Usage: EditBox:SetCursorPosition(position)");
+        return 0;
+    }
+    const int pos = static_cast<int>(Game::Lua::ToNumber(L, 2));
+    reinterpret_cast<SetCursorByte_t>(
+        Offsets::FUN_EDITBOX_SET_CURSOR_BYTE)(eb, pos);
+    reinterpret_cast<CollapseSelection_t>(
+        Offsets::FUN_EDITBOX_COLLAPSE_SELECTION)(eb);
+    // COLLAPSE_SELECTION moves selStart/selEnd but doesn't flag them; set the
+    // selection-dirty bit (2) so any highlight from before is cleared on the
+    // next paint. SET_CURSOR_BYTE already set the cursor-dirty bit (4).
+    Game::Ref<uint32_t>(eb, Offsets::OFF_EDITBOX_FLAGS) |= 2;
+    return 0;
+}
+
+int __fastcall Script_GetCursorPosition(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::Error(L, "Usage: EditBox:GetCursorPosition()");
+        return 0;
+    }
+    Game::Lua::PushNumber(L, static_cast<double>(
+        Game::Read<int>(eb, Offsets::OFF_EDITBOX_CURSOR_BYTE)));
+    return 1;
+}
+
+// The caret as a 0-based CHARACTER index (UTF-8 codepoints before the caret),
+// vs GetCursorPosition's byte offset. Equal for ASCII; differs once the text
+// holds multibyte characters.
+int __fastcall Script_GetUTF8CursorPosition(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::Error(L, "Usage: EditBox:GetUTF8CursorPosition()");
+        return 0;
+    }
+    const int cursorByte = Game::Read<int>(eb, Offsets::OFF_EDITBOX_CURSOR_BYTE);
+    const int chars = reinterpret_cast<CountChars_t>(
+        Offsets::FUN_EDITBOX_COUNT_CHARS)(eb, 0, cursorByte);
+    Game::Lua::PushNumber(L, static_cast<double>(chars));
+    return 1;
+}
+
+// Drop the current selection without moving the caret. Collapsing selection to
+// the caret (selStart = selEnd = cursor) is exactly what the engine's own
+// helper does; vanilla can only clear a selection via HighlightText(0, 0),
+// which yanks it to offset 0 instead of leaving the caret in place.
+int __fastcall Script_ClearHighlightText(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::Error(L, "Usage: EditBox:ClearHighlightText()");
+        return 0;
+    }
+    reinterpret_cast<CollapseSelection_t>(
+        Offsets::FUN_EDITBOX_COLLAPSE_SELECTION)(eb);
+    Game::Ref<uint32_t>(eb, Offsets::OFF_EDITBOX_FLAGS) |= 2;
+    return 0;
+}
+
+// True when this edit box currently owns keyboard focus. The engine tracks the
+// focused box in one global (written by SetFocus / cleared by ClearFocus), so
+// focus is just pointer identity against it.
+int __fastcall Script_HasFocus(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::PushBool(L, false);
+        return 1;
+    }
+    Game::Lua::PushBool(L,
+        eb == Game::Read<void *>(Offsets::VAR_FOCUSED_EDITBOX));
+    return 1;
+}
+
+// True when the box holds any text (its byte length is non-zero).
+int __fastcall Script_HasText(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::PushBool(L, false);
+        return 1;
+    }
+    Game::Lua::PushBool(L,
+        Game::Read<int>(eb, Offsets::OFF_EDITBOX_TEXT_LENGTH) > 0);
+    return 1;
+}
+
+// SetHighlightColor(r, g, b [, a]) — the color of the text-selection highlight.
+// The engine paints the selection with three Texture regions (start-line,
+// middle-block, end-line); their vertex color is the highlight color, so set
+// it on all three via the engine's own region color setter. Colors are 0..1;
+// alpha defaults to 1. Takes effect on the next selection paint.
+int __fastcall Script_SetHighlightColor(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr || !Game::Lua::IsNumber(L, 2) ||
+        !Game::Lua::IsNumber(L, 3) || !Game::Lua::IsNumber(L, 4)) {
+        Game::Lua::Error(L, "Usage: EditBox:SetHighlightColor(r, g, b [, a])");
+        return 0;
+    }
+    const uint32_t r = ColorByte(L, 2, 1.0);
+    const uint32_t g = ColorByte(L, 3, 1.0);
+    const uint32_t b = ColorByte(L, 4, 1.0);
+    const uint32_t a = ColorByte(L, 5, 1.0);
+    const uint32_t packed = b | (g << 8) | (r << 16) | (a << 24); // {b,g,r,a}
+    auto setColor = reinterpret_cast<RegionSetColor_t>(
+        Offsets::FUN_FONTSTRING_SET_COLOR);
+    for (int off = Offsets::OFF_EDITBOX_HIGHLIGHT_REGION;
+         off <= Offsets::OFF_EDITBOX_HIGHLIGHT_REGION + 8; off += 4) {
+        void *region = Game::Read<void *>(eb, off);
+        if (region != nullptr)
+            setColor(region, &packed);
+    }
+    return 0;
+}
+
+// GetHighlightColor() -> r, g, b, a (each 0..1). Reads the color off the first
+// highlight region; a region with no explicit color reads back white (opaque).
+int __fastcall Script_GetHighlightColor(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::Error(L, "Usage: EditBox:GetHighlightColor()");
+        return 0;
+    }
+    uint32_t packed = 0xFFFFFFFF;
+    void *region = Game::Read<void *>(eb, Offsets::OFF_EDITBOX_HIGHLIGHT_REGION);
+    if (region != nullptr)
+        reinterpret_cast<RegionGetColor_t>(Offsets::FUN_REGION_GET_COLOR)(
+            region, &packed);
+    const double inv = 1.0 / 255.0;
+    Game::Lua::PushNumber(L, ((packed >> 16) & 0xff) * inv); // r
+    Game::Lua::PushNumber(L, ((packed >> 8) & 0xff) * inv);  // g
+    Game::Lua::PushNumber(L, (packed & 0xff) * inv);         // b
+    Game::Lua::PushNumber(L, ((packed >> 24) & 0xff) * inv); // a
+    return 4;
+}
+
+// Empties the up/down input history, keeping the line limit so the box keeps
+// recording afterward. The engine's SetHistoryLines internal frees the whole
+// ring at max 0, so clear = free (0) then reallocate at the saved max — which
+// drops every entry and resets the write position. No-op when history was
+// never enabled (max 0).
+int __fastcall Script_ClearHistory(void *L) {
+    void *eb = Game::Lua::ResolveObject(L, 1);
+    if (eb == nullptr) {
+        Game::Lua::Error(L, "Usage: EditBox:ClearHistory()");
+        return 0;
+    }
+    const int max = Game::Read<int>(eb, Offsets::OFF_EDITBOX_HISTORY_MAX);
+    if (max > 0) {
+        auto setMax = reinterpret_cast<SetHistoryMax_t>(
+            Offsets::FUN_EDITBOX_SET_HISTORY_MAX);
+        setMax(eb, 0);
+        setMax(eb, max);
+    }
+    return 0;
+}
+
+const Game::Lua::FrameMethodEntry g_methods[] = {
+    {"SetCursorPosition", &Script_SetCursorPosition},
+    {"GetCursorPosition", &Script_GetCursorPosition},
+    {"GetUTF8CursorPosition", &Script_GetUTF8CursorPosition},
+    {"ClearHighlightText", &Script_ClearHighlightText},
+    {"HasFocus", &Script_HasFocus},
+    {"HasText", &Script_HasText},
+    {"SetHighlightColor", &Script_SetHighlightColor},
+    {"GetHighlightColor", &Script_GetHighlightColor},
+    {"ClearHistory", &Script_ClearHistory},
+};
+
+void RegisterLuaFunctions() {
+    Game::Lua::RegisterFrameMethods(
+        reinterpret_cast<void *>(Offsets::VAR_EDITBOX_METHOD_REGISTRY),
+        g_methods,
+        static_cast<int>(sizeof(g_methods) / sizeof(g_methods[0])));
+}
+
+const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace
+
+} // namespace EditBox::Methods

src/interface/Version.cpp

@@ -0,0 +1,46 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// `INTERFACE_VERSION` global — the client's interface (TOC) version number,
+// 11200 on this client. Read from the engine's own accessor (the same value
+// the addon loader compares each `## Interface:` against) rather than a
+// literal, and re-published on every `/reload` via the standard
+// `ModuleAutoRegister` flow. It is a true fixed client constant, so it is a
+// global number like `CLASSIC_API_VERSION`, not a function.
+
+#include "Game.h"
+#include "Offsets.h"
+
+#include <cstdint>
+
+namespace Interface::Version {
+
+namespace {
+
+using ClientIfaceVer_t = uint32_t(__cdecl *)();
+
+void RegisterLuaFunctions() {
+    void *L = Game::Lua::State();
+    if (L == nullptr)
+        return;
+    const uint32_t version = reinterpret_cast<ClientIfaceVer_t>(
+        static_cast<uintptr_t>(Offsets::FUN_ADDON_CLIENT_INTERFACE_VERSION))();
+    Game::Lua::SetGlobalNumber(L, "INTERFACE_VERSION",
+                               static_cast<double>(version));
+}
+
+const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace
+
+} // namespace Interface::Version

src/table/Length.cpp

@@ -49,31 +49,49 @@
 //      `n` field is the 5.0 vararg-table contract (`arg` = {n=3, holes}),
 //      where trailing nils are intentional — healing it would corrupt
 //      vararg counts.
-//   3. `t[n]` nil, no `t.n`: scan down for the true border `b`. Heal to `b`
-//      ONLY when the stored length overshoots it by more than one slot
-//      (`n - b > 1`) — a cleared-and-reused table (Dewdrop's menus) is stale
-//      by many slots. When it overshoots by exactly one (`n - b == 1`), the
-//      nil at slot `n` is a legitimate 5.0 append slot — `table.insert(t, nil)`
-//      writes `t[n]=nil` and `setn(n)` — so keep the stored length; healing it
-//      would make the NEXT append overwrite that slot and shift every element
-//      after it down by one (issue #36: Ace2/Waterfall's `{key,val,…}` builders
-//      that append a nil value corrupt silently). Read-only — no write-back,
-//      so a length read never mutates state; the engine's own `table.insert`
-//      calls `luaL_setn(n+1)` on the next append, which re-syncs the stored
-//      length by itself.
+//   3. `t[n]` nil, no `t.n`: scan down for the true border `b` and heal to
+//      it (the 5.1 answer) — UNLESS the nil at slot `n` is a deliberate
+//      `table.insert(t, nil)` append slot, detected by the writer-side mark
+//      below, in which case keep the stored length. Read-only — no
+//      write-back, so a length read never mutates state; the engine's own
+//      `table.insert` calls `luaL_setn(n+1)` on the next append, which
+//      re-syncs the stored length by itself.
 //
-// Why the gap test and not caller-gating: both Dewdrop (clear + rebuild via
-// `table.insert`, Length.cpp's raison d'être) and Waterfall reach here THROUGH
-// `table.insert`, so the caller can't tell them apart — only the staleness gap
-// can. A cleared table is empty below `n` (large gap); a deliberate nil append
-// is dense below `n` (gap 1). The gap is a heuristic (two consecutive nil
-// appends would read as a cleared table), but consecutive nil appends are
-// pathological, while single nil appends between real values are the common
-// Ace2 idiom.
+// Why a writer-side mark (the tinsert co-hook) and not a state heuristic: a
+// deliberate 5.0 nil append (`table.insert(t, nil)` — writes `t[n]=nil` +
+// `setn(n)`; issue #36: Waterfall's `{key,val,…}` builders append a nil for
+// every option without a passValue, and the next insert must land AFTER the
+// reserved slot) and a cleared-and-reused table that happens to be stale by
+// exactly one (a one-element table pairs-cleared, or a recycled table whose
+// previous life was one slot longer — Tablet-2.0's `del()`/`copy()` pool
+// recycles per tooltip refresh, so this is everyday traffic) leave the table
+// in BYTE-IDENTICAL states: stored `n`, dense below, `t[n]` nil, no `t.n`.
+// No inspection of the table can split them, and caller-gating can't either
+// (both reach here through `table.insert`). v1.12.8 tried a staleness-gap
+// heuristic (keep when `n - b == 1`) and it corrupted the second group —
+// issue #39, FuBar/Tablet/Dewdrop menus and tooltips shifting by one with a
+// nil hole at slot 1. Only the WRITER knows which dialect the table speaks,
+// and the write is observable: a co-hook on `table.insert`
+// (FUN_LUA_TABLE_INSERT) records `t → storedN` in a weak-keyed registry
+// table whenever the two-arg form appends a literal nil. Rule 3 keeps the
+// stored length only for a marked table whose mark still equals `n`; every
+// unmarked off-by-one table heals. A stale mark dies on its own: any later
+// append/remove moves the stored length away from the recorded value, and
+// the weak key lets a dead table's entry be collected.
+//
+// Note real Lua 5.1 gives the HEAL answer even for the deliberate append
+// (`#`-based tinsert drops a trailing nil and the next insert overwrites
+// it), so keeping the slot is deliberately 5.0-native behavior for
+// 5.0-dialect writers — Waterfall's builder runs on the 5.0 `arg` vararg
+// table and predates 5.1. 5.1-dialect code never relies on insert(t, nil)
+// reserving a slot, because on real 5.1 it doesn't.
+//
+// Positional nil insertion (`table.insert(t, pos, nil)`) is not marked and
+// heals; no consumer is known, and 5.0 itself makes it a shifted no-op.
 //
 // `table.setn` itself still works for code that calls it — the heal only
-// changes the answer when the stored length points more than one slot past
-// the border, which is the same answer real 5.1 would give.
+// changes the answer when the stored length points past the border and no
+// mark vouches for it, which is the same answer real 5.1 would give.
 
 #include "Game.h"
 #include "Offsets.h"
@@ -86,6 +104,11 @@ using LuaLGetN_t = int(__fastcall *)(void *L, int idx);
 using RawGetI_t = void(__fastcall *)(void *L, int idx, int n);
 
 LuaLGetN_t g_getnOriginal = nullptr;
+Game::Lua::CFunction g_tinsertOriginal = nullptr;
+
+// Registry key of the weak-keyed mark table: `marks[t] = storedN` recorded
+// at the moment `table.insert(t, nil)` reserved slot `storedN`.
+constexpr char kMarkKey[] = "ClassicAPI_TrailingNilMark";
 
 // True if t[k] (rawgeti) is nil. Balances the stack.
 bool SlotIsNil(void *L, int absIdx, int k) {
@@ -95,6 +118,64 @@ bool SlotIsNil(void *L, int absIdx, int k) {
     return isNil;
 }
 
+// Pushes the mark table, creating `registry[kMarkKey] = setmetatable({},
+// {__mode = "k"})` on first use (per Lua state — the registry survives
+// `/reload` because the state is reused, and the marked tables survive with
+// it). Leaves exactly one value on the stack.
+void PushMarkTable(void *L) {
+    Game::Lua::PushString(L, kMarkKey);
+    Game::Lua::RawGet(L, Game::Lua::REGISTRY_INDEX);
+    if (Game::Lua::Type(L, -1) == Game::Lua::TYPE_TABLE)
+        return;
+    Game::Lua::SetTop(L, -2);      // pop the nil.            []
+    Game::Lua::NewTable(L);        //                         [marks]
+    Game::Lua::NewTable(L);        //                         [marks, meta]
+    Game::Lua::PushString(L, "__mode");
+    Game::Lua::PushString(L, "k");
+    Game::Lua::RawSet(L, -3);      // meta.__mode = "k".      [marks, meta]
+    Game::Lua::SetMetatable(L, -2);// pops meta.              [marks]
+    Game::Lua::PushString(L, kMarkKey);
+    Game::Lua::PushValue(L, -2);   //                         [marks, key, marks]
+    Game::Lua::RawSet(L, Game::Lua::REGISTRY_INDEX); //       [marks]
+}
+
+// True when `marks[t] == n` — the nil at slot `n` was written by a
+// deliberate `table.insert(t, nil)` and nothing has moved the stored
+// length since. Balances the stack.
+bool HasTrailingNilMark(void *L, int absIdx, int n) {
+    PushMarkTable(L);                 // [marks]
+    Game::Lua::PushValue(L, absIdx);  // [marks, t]
+    Game::Lua::RawGet(L, -2);         // [marks, marks[t]]
+    const bool match =
+        Game::Lua::Type(L, -1) == Game::Lua::TYPE_NUMBER &&
+        static_cast<int>(Game::Lua::ToNumber(L, -1)) == n;
+    Game::Lua::SetTop(L, -3);         // pop both
+    return match;
+}
+
+// Co-hook on the engine's `table.insert` (both `table.insert` and the
+// `tinsert` alias are this one C function). The two-arg form appending a
+// literal nil is the 5.0 idiom that must keep its reserved slot; record it
+// so rule 3 can tell it apart from an identically-shaped stale table. The
+// detection runs before the original (the arg stack is caller-owned, so
+// index 1 still holds the table afterwards); the mark reads the raw stored
+// length the original's `luaL_setn` just wrote.
+int __fastcall TableInsert_h(void *L) {
+    const bool nilAppend = Game::Lua::GetTop(L) == 2 &&
+                           Game::Lua::Type(L, 1) == Game::Lua::TYPE_TABLE &&
+                           Game::Lua::Type(L, 2) == Game::Lua::TYPE_NIL;
+    const int ret = g_tinsertOriginal(L);
+    if (nilAppend) {
+        const int storedN = g_getnOriginal(L, 1);
+        PushMarkTable(L);              // [marks]
+        Game::Lua::PushValue(L, 1);    // [marks, t]
+        Game::Lua::PushNumber(L, storedN);
+        Game::Lua::RawSet(L, -3);      // marks[t] = storedN.  [marks]
+        Game::Lua::SetTop(L, -2);      // pop marks
+    }
+    return ret;
+}
+
 int __fastcall LuaLGetN_h(void *L, int idx) {
     const int n = g_getnOriginal(L, idx);
     if (n <= 0)
@@ -125,20 +206,24 @@ int __fastcall LuaLGetN_h(void *L, int idx) {
     while (b > 0 && SlotIsNil(L, absIdx, b))
         --b;
 
-    // Overshoots the border by exactly one slot: a legitimate 5.0 nil append
-    // (`table.insert(t, nil)`) sits in a dense array, not a cleared table.
-    // Keep the stored length so the next append lands after the nil, not on it.
-    if (n - b <= 1)
+    // Stored length exactly one past the border: either a deliberate
+    // `table.insert(t, nil)` reserved slot (keep — issue #36) or a cleared /
+    // recycled table stale by one (heal — issue #39). The states are
+    // identical; only the writer-side mark recorded by `TableInsert_h` can
+    // tell them apart.
+    if (n - b == 1 && HasTrailingNilMark(L, absIdx, n))
         return n;
 
-    // Stale by more than one slot — a cleared-and-reused table. Heal to the
-    // border, the 5.1 answer.
+    // Stale — heal to the border, the 5.1 answer.
     return b;
 }
 
 const Game::HookAutoRegister _hook{Offsets::LUAL_GETN,
                                    reinterpret_cast<void *>(&LuaLGetN_h),
                                    reinterpret_cast<void **>(&g_getnOriginal)};
+const Game::HookAutoRegister _hookInsert{
+    Offsets::FUN_LUA_TABLE_INSERT, reinterpret_cast<void *>(&TableInsert_h),
+    reinterpret_cast<void **>(&g_tinsertOriginal)};
 
 } // namespace