table: reset getn length counter in table.wipe

table.wipe nil'd every key via lua_next + rawset(nil) but left the
Lua 5.0 length counter untouched. In 5.0 a table's table.insert/getn
length lives out of band from its keys (a t.n field, else a weak
sizes[t] entry in the registry's LUA_SIZES table), so it survived the
clear. After a wipe, getn stayed at its old value and subsequent
table.insert appended past the wiped slots -- t[1] stayed nil. The
3.3.5 (Lua 5.1) twipe this was ported from has no getn legacy, which
is why the ported logic looked complete.

Fix: call luaL_setn(L, 1, 0) after the clear loop. Bound the engine's
luaL_setn (FUN_006f4ea0, verified against 5.0.2; located via
table.insert FUN_007fb6b0) as Game::Lua::SetN.

Repro before: table.insert(t,1); table.insert(t,2); table.wipe(t);
table.insert(t,3) -> getn 3, t[1] nil, t[3]=3.
After: getn 2, t[1]=3, t[2]=4. Verified in-game.

README.md

@@ -39,7 +39,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Gossip](docs/API.md#gossip) | `C_GossipInfo.CloseGossip`, `C_GossipInfo.GetActiveQuests`, `C_GossipInfo.GetAvailableQuests`, `C_GossipInfo.GetNumActiveQuests`, `C_GossipInfo.GetNumAvailableQuests`, `C_GossipInfo.GetNumOptions`, `C_GossipInfo.GetOptions`, `C_GossipInfo.GetText`, `C_GossipInfo.SelectActiveQuest`, `C_GossipInfo.SelectAvailableQuest`, `C_GossipInfo.SelectOption`, `C_GossipInfo.SelectOptionByIndex` |
 | [GameTooltip](docs/API.md#gametooltip) | `GameTooltip:GetGameObject`, `GameTooltip:GetItem`, `GameTooltip:GetOwner`, `GameTooltip:GetSpell`, `GameTooltip:GetUnitGUID`, `GameTooltip:HasGameObject`, `GameTooltip:HasItem`, `GameTooltip:HasSpell`, `GameTooltip:HasUnit`, `GameTooltip:IsEquippedItem`, `GameTooltip:SetEquipmentSet`, `GameTooltip:SetHyperlinkCompareItem`, `GameTooltip:SetInventoryItemByID`, `GameTooltip:SetItemByGUID`, `GameTooltip:SetItemByID`, `GameTooltip:SetSpellByID`, `GameTooltip:SetTalentByID`, `GameTooltip:SetUnitAura`, `OnTooltipSetItem` (script) |
 | [Hooks](docs/API.md#hooks) | `hooksecurefunc` |
-| [Input](docs/API.md#input) | `IsLeftAltKeyDown`, `IsLeftControlKeyDown`, `IsLeftShiftKeyDown`, `IsModifierKeyDown`, `IsMouseButtonDown`, `IsRightAltKeyDown`, `IsRightControlKeyDown`, `IsRightShiftKeyDown` |
+| [Input](docs/API.md#input) | `GetMouseButtonClicked`, `IsLeftAltKeyDown`, `IsLeftControlKeyDown`, `IsLeftShiftKeyDown`, `IsModifierKeyDown`, `IsMouseButtonDown`, `IsRightAltKeyDown`, `IsRightControlKeyDown`, `IsRightShiftKeyDown` |
 | [Instance](docs/API.md#instance) | `GetInstanceInfo` |
 | [Item](docs/API.md#item) | `C_Item.DoesItemExist`, `C_Item.DoesItemExistByID`, `C_Item.EquipItemByName`, `C_Item.GetCurrentItemLevel`, `C_Item.GetDetailedItemLevelInfo`, `C_Item.GetEnchantInfo`, `C_Item.GetItemCount`, `C_Item.GetItemFamily`, `C_Item.GetItemGUID`, `C_Item.GetItemIcon`, `C_Item.GetItemIconByID`, `C_Item.GetItemID`, `C_Item.GetItemInfoInstant`, `C_Item.GetItemInventorySlotInfo`, `C_Item.GetItemInventorySlotKey`, `C_Item.GetItemInventoryType`, `C_Item.GetItemInventoryTypeByID`, `C_Item.GetItemLink`, `C_Item.GetItemLocation`, `C_Item.GetItemMaxStackSize`, `C_Item.GetItemMaxStackSizeByID`, `C_Item.GetItemName`, `C_Item.GetItemNameByID`, `C_Item.GetItemQuality`, `C_Item.GetItemQualityByID`, `C_Item.GetItemSellPrice`, `C_Item.GetItemSellPriceByID`, `C_Item.GetItemSetID`, `C_Item.GetItemSetIDByID`, `C_Item.GetItemSetInfo`, `C_Item.GetItemSpell`, `C_Item.GetItemStatDelta`, `C_Item.GetItemStats`, `C_Item.GetItemSubClassInfo`, `C_Item.GetItemUniqueness`, `C_Item.GetItemUniquenessByID`, `C_Item.GetStackCount`, `C_Item.GetWeaponEnchantInfo`, `C_Item.IsBound`, `C_Item.IsEquippableItem`, `C_Item.IsEquippedItem`, `C_Item.IsItemDataCached`, `C_Item.IsItemDataCachedByID`, `C_Item.IsItemGUIDInInventory`, `C_Item.IsItemOpenable`, `C_Item.IsLocked`, `C_Item.LockItem`, `C_Item.LockItemByGUID`, `C_Item.UnlockAllItems`, `C_Item.UnlockItem`, `C_Item.RequestLoadItemData`, `C_Item.RequestLoadItemDataByID`, `C_Item.UseAtCursor`, `C_Item.UseAtUnit`, `C_Item.UseItemByName`, `GetAuctionItemID`, `GetAuctionSellItemID`, `GetAverageItemLevel`, `GetCraftReagentItemID`, `GetInboxItemID`, `GetInventoryItemDurability`, `GetInventoryItemID`, `GetInventoryItemsForSlot`, `GetInventoryItemRepairCost`, `GetItemIcon`, `GetLootRollItemID`, `GetLootSlotItemID`, `GetMerchantItemID`, `GetQuestItemID`, `GetQuestLogItemID`, `GetTradePlayerItemID`, `GetTradeSkillItemID`, `GetTradeSkillReagentItemID`, `GetTradeTargetItemID`, `OffhandHasWeapon` |
 | [Loot](docs/API.md#loot) | `C_Loot.GetNearbyLootableUnits`, `C_Loot.GetLastScanResults`, `C_Loot.IsScanInProgress`, `C_Loot.LootUnit`, `C_Loot.LootUnitItem`, `C_Loot.ScanNearbyLoot` |

docs/API.md

@@ -194,6 +194,7 @@ build instructions.
   - [`IsLeftAltKeyDown()` / `IsRightAltKeyDown()`](#isleftaltkeydown--isrightaltkeydown)
   - [`IsModifierKeyDown()`](#ismodifierkeydown)
   - [`IsMouseButtonDown([button])`](#ismousebuttondownbutton)
+  - [`GetMouseButtonClicked()`](#getmousebuttonclicked)
 
 - [Instance](#instance)
   - [`GetInstanceInfo()`](#getinstanceinfo)
@@ -4297,6 +4298,38 @@ if IsMouseButtonDown("RightButton") then
 end
 ```
 
+### `GetMouseButtonClicked()`
+
+Returns the name of the button responsible for the mouse handler
+currently running (`"LeftButton"`, `"RightButton"`, `"MiddleButton"`,
+`"Button4"`, `"Button5"`), or `nil` when no click is being handled.
+
+Modern addons call this inside a mouse handler (`OnClick`,
+`OnMouseDown`, `OnMouseUp`, `OnDragStart`, …) to learn which button
+drove it — an alternative to reading vanilla's `arg1`, and readable
+from nested helper functions where `arg1` isn't in scope. The value
+is captured by the same `WH_GETMESSAGE` hook behind
+`GLOBAL_MOUSE_DOWN` / `GLOBAL_MOUSE_UP`, then evicted a couple of
+frames later so — matching the real API — it reads `nil` outside a
+handler rather than lingering as the last click forever.
+
+The button stays readable for the whole frame its click lands in (so
+multiple addons hooking the same `OnClick` all see it), and while a
+button is physically held (so `OnDragStart` reads it). It is a
+best-effort replica: WoW dispatches these handlers deferred from the
+OS message, so eviction is time-based (per-frame) rather than exactly
+bracketed around the handler as on retail. Values can therefore
+linger ~2 frames past a click — harmless, since it's only meaningful
+inside a mouse handler.
+
+```lua
+button:SetScript("OnClick", function()
+    if GetMouseButtonClicked() == "RightButton" then
+        -- right-click behavior
+    end
+end)
+```
+
 ## Instance
 
 ### `GetInstanceInfo()`
@@ -7037,12 +7070,18 @@ Three population sources feed the cache when fully enabled:
 Storage:
 
 - `WTF\Account\<account>\ClassicAPI.txt` — account-level settings
-  (`PersistentNameCacheEnabled`, `NameCacheScanEnabled`).
-- `WTF\Account\<account>\<realm>\ClassicAPI_NameCache.txt` —
-  per-realm cache. Tab-separated text, ~30 bytes/entry,
-  hand-editable. Shared across all characters on the same
-  account+realm (a 50-character bank alt's chat scraping doesn't
-  double the storage cost).
+  (`PersistentNameCacheEnabled`, `NameCacheScanEnabled`). The
+  opt-in toggles stay per-account.
+- `WTF\ClassicAPI\<realmList>\<realm>\ClassicAPI_NameCache.txt` —
+  per-realm cache, **shared across every account on the same
+  server**. Keyed by the realmlist address (unambiguous server
+  identity, can't collide across unrelated private servers) plus the
+  realm name — so alts on different accounts pool into one file
+  rather than each rebuilding their own. Tab-separated text,
+  ~30 bytes/entry, hand-editable. On first load with no shared file
+  yet, a pre-existing per-account cache
+  (`WTF\Account\<account>\<realm>\ClassicAPI_NameCache.txt`) is
+  migrated in automatically.
 
 ### `GetPlayerInfoByGUID(guid)`
 

src/Game.cpp

@@ -56,7 +56,8 @@ namespace Lua {
     F(NewThread,   lua_newthread,   LUA_NEW_THREAD)   \
     F(Resume,      lua_resume,      LUA_RESUME)       \
     F(Yield,       lua_yield,       LUA_YIELD)        \
-    F(ArgError,    luaL_argerror,   LUAL_ARG_ERROR)
+    F(ArgError,    luaL_argerror,   LUAL_ARG_ERROR)   \
+    F(SetN,        luaL_setn,       LUAL_SETN)
 
 #define CLASSICAPI_BIND_LUA(Name, Typedef, Offset) \
     const Typedef##_t Name = reinterpret_cast<Typedef##_t>(Offsets::Offset);

src/Game.h

@@ -99,6 +99,7 @@ using lua_newthread_t = void *(__fastcall *)(void *L);
 using lua_resume_t = int(__fastcall *)(void *L, int nargs);
 using lua_yield_t = int(__fastcall *)(void *L, int nresults);
 using luaL_argerror_t = void(__fastcall *)(void *L, int narg, const char *msg);
+using luaL_setn_t = void(__fastcall *)(void *L, int t, int n);
 
 extern const lua_isnumber_t IsNumber;
 extern const lua_isstring_t IsString;
@@ -140,6 +141,7 @@ extern const lua_newthread_t NewThread;
 extern const lua_resume_t Resume;
 extern const lua_yield_t Yield;
 extern const luaL_argerror_t ArgError;
+extern const luaL_setn_t SetN;
 
 // Returns the global `lua_State *` (read on demand from the engine's global).
 // Callable outside a Lua callback, e.g. during LoadScriptFunctions setup.

src/Offsets.h

@@ -3476,6 +3476,17 @@ enum Offsets {
     // '%s' (%s)" (or "calling '%s' on bad self (%s)" for method-style
     // calls) and calls `lua_error`. Doesn't return.
     LUAL_ARG_ERROR = 0x6F4810,
+    // `luaL_setn(L, t, n)` — Lua 5.0 auxlib table-length setter
+    // (verified: `FUN_006f4ea0`, __fastcall L/ecx, t/edx, n/stack,
+    // RET 4). Matches 5.0.2 `luaL_setn`: sets `t.n = n` if a numeric
+    // `n` field exists, else `sizes[t] = n` in the registry's weak
+    // LUA_SIZES table. Found via `table.insert` (`FUN_007fb6b0`), which
+    // calls it to record the new length; `luaL_getn` is `FUN_006f5050`.
+    // Needed by `table.wipe` to reset the length after clearing keys —
+    // the length is out-of-band from the keys, so a `lua_next` +
+    // `rawset(nil)` clear leaves it stale and subsequent `table.insert`
+    // appends past the wiped slots.
+    LUAL_SETN = 0x6F4EA0,
     // `lua_iscfunction(L, idx)` — returns 1 if value is a function
     // closure with the `isC` byte set (`Closure.c.isC == 1`), 0
     // otherwise. Used by `coroutine.create` to reject C functions

src/input/GlobalMouse.cpp

@@ -24,6 +24,26 @@
 // as the events (single source of truth — events firing and the
 // state being readable happen at the same point in the pipeline).
 //
+// `GetMouseButtonClicked()` — the button name of the most recent
+// mouse button message (`"LeftButton"` / … / `"Button5"`), or nil
+// when no click is being handled. Modern addons call it inside a
+// mouse handler to learn which button drove it; the value is evicted
+// shortly after, so — like the real API — it reads nil outside a
+// handler rather than returning a stale last-click forever.
+//
+// Modern WoW backs this with a frame-manager field set right before a
+// mouse handler runs and cleared right after (verified in 3.3.5:
+// `GetMouseButtonClicked` pushes `[frameMgr + 0x1234]`, nil when that
+// field is null). We can't bracket the handler the same way here: the
+// `WH_GETMESSAGE` hook sees the button at message-dequeue, but WoW
+// dispatches the frame-script mouse handlers *deferred* (during the
+// frame update, not the message pump). So instead we capture the
+// button on the message and evict it from the per-frame `WorldTick`
+// once a couple of quiet ticks pass with no button held — the value
+// survives the whole frame its click lands in (so every handler,
+// including multiple addons hooking one `OnClick`, sees it) then
+// clears. A held button keeps it set so `OnDragStart` still reads it.
+//
 // Same `WH_GETMESSAGE` thread-message hook pattern as
 // [Input::Modifier](Modifier.cpp): we intercept the WM_*BUTTON*
 // messages on the engine's main thread *before* dispatch. The hook
@@ -33,6 +53,7 @@
 
 #include "Game.h"
 #include "event/Custom.h"
+#include "tick/WorldTick.h"
 
 #include <cstdint>
 #include <cstring>
@@ -59,6 +80,24 @@ constexpr uint32_t MASK_ANY_BUTTON = 0x1F;
 
 uint32_t g_mouseButtonMask = 0;
 
+// Name of the button from the most recent mouse-button message, or
+// nullptr when no click is being handled. Points at one of
+// DecodeButton's string literals (stable for the process lifetime),
+// so storing the pointer is safe. `lua_pushstring(L, nullptr)`
+// tail-jumps to pushnil, so a null here surfaces as nil to the Lua
+// caller with no extra branch. Set on each button message; evicted by
+// EvictTick (see the header note on GetMouseButtonClicked).
+const char *g_lastButton = nullptr;
+
+// Set true whenever g_lastButton is (re)assigned, so EvictTick can
+// tell a just-clicked frame from a quiet one. Number of consecutive
+// quiet ticks (no activity, nothing held) required before eviction —
+// >1 so a handler dispatched a frame after its message still reads
+// the button.
+bool g_buttonActivity = false;
+int g_quietTicks = 0;
+constexpr int kQuietTicksToEvict = 2;
+
 HHOOK g_msgHook = nullptr;
 
 // Maps WM_*BUTTON{DOWN,UP} → ("LeftButton"|..., isDown). Returns
@@ -101,6 +140,13 @@ void ProcessMouseMessage(UINT msg, WPARAM wParam) {
     if (name == nullptr)
         return;
 
+    // Capture for GetMouseButtonClicked on both press and release —
+    // during an OnClick / OnMouseUp handler the "clicked" button is the
+    // one just released, same as the press for a normal click.
+    g_lastButton = name;
+    g_buttonActivity = true;
+    g_quietTicks = 0;
+
     const int bitIdx = NameToBitIdx(name);
     if (bitIdx >= 0) {
         const uint32_t bit = 1u << bitIdx;
@@ -136,6 +182,39 @@ int __fastcall Script_IsMouseButtonDown(void *L) {
     return 1;
 }
 
+int __fastcall Script_GetMouseButtonClicked(void *L) {
+    // Null → pushnil (the engine's pushstring tail-jumps on NULL), so
+    // callers outside a mouse handler see nil, matching the modern API.
+    Game::Lua::PushString(L, g_lastButton);
+    return 1;
+}
+
+// Per-frame eviction of g_lastButton. Runs at the tail of each frame's
+// world tick. While a button is held we keep the value (drag handlers
+// still read it) and reset the quiet counter. A frame that saw a fresh
+// button message consumes its activity flag but doesn't yet evict —
+// that one-frame grace lets a handler dispatched the frame after its
+// message still read the button. Only after kQuietTicksToEvict ticks
+// with nothing held and no activity do we clear, so outside a click
+// GetMouseButtonClicked reads nil instead of a stale last-click.
+void EvictTick() {
+    if (g_lastButton == nullptr)
+        return;
+    if (g_mouseButtonMask != 0) {
+        g_quietTicks = 0;
+        return;
+    }
+    if (g_buttonActivity) {
+        g_buttonActivity = false;
+        g_quietTicks = 0;
+        return;
+    }
+    if (++g_quietTicks >= kQuietTicksToEvict) {
+        g_lastButton = nullptr;
+        g_quietTicks = 0;
+    }
+}
+
 LRESULT CALLBACK GetMsgHook(int code, WPARAM wParam, LPARAM lParam) {
     // Only process when the message is being removed from the queue
     // (`PM_REMOVE` / `GetMessage`); `PM_NOREMOVE` peeks would deliver
@@ -157,11 +236,14 @@ void InstallHook() {
 void RegisterLuaFunctions() {
     Game::Lua::RegisterGlobalFunction("IsMouseButtonDown",
                                       &Script_IsMouseButtonDown);
+    Game::Lua::RegisterGlobalFunction("GetMouseButtonClicked",
+                                      &Script_GetMouseButtonClicked);
     InstallHook();
 }
 
 const Event::Custom::AutoReserve _reserveDown{kDownEvent};
 const Event::Custom::AutoReserve _reserveUp{kUpEvent};
+const Tick::WorldTick::AutoSubscribe _evict{&EvictTick};
 const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
 
 } // namespace

src/player/NameCache.cpp

@@ -23,13 +23,19 @@
 //       parse callbacks, and the registry handles load/save so neither
 //       this module nor `Charlist::Order` clobbers the other's lines.
 //
-//   `WTF\Account\<acct>\<realm>\ClassicAPI_NameCache.txt`
-//       Per-realm cache contents. v2 format. One entry per line:
-//           `guidHi  guidLo  classID  raceID  sex  name`
+//   `WTF\ClassicAPI\<realmList>\<realm>\ClassicAPI_NameCache.txt`
+//       Per-realm cache contents, SHARED across every account on the
+//       same server. Keyed by realmlist address (unambiguous server
+//       identity — can't collide across unrelated private servers) plus
+//       the realm name, rather than by account, so alts on different
+//       accounts pool into one file. Not under `Account\`, so we create
+//       the directory tree ourselves. v4 format. One entry per line:
+//           `name  guid  classID  raceID  sex`
 //       (fields tab-separated). Loaded once the realm name is
-//       available post-login. Saved when (a) a recent write hasn't
-//       been flushed AND (b) at least 30 seconds have elapsed since
-//       the prior save, OR (c) DLL teardown / `Flush()` is called.
+//       available post-login (migrating a pre-existing per-account file
+//       in on first load). Saved when (a) a recent write hasn't been
+//       flushed AND (b) at least 30 seconds have elapsed since the prior
+//       save, OR (c) DLL teardown / `Flush()` is called.
 //
 // Population sources:
 //   1. The engine's NameCache writer (`FUN_PLAYER_INFO_CACHE_WRITE`)
@@ -69,6 +75,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <fstream>
+#include <istream>
 #include <ostream>
 #include <sstream>
 #include <string>
@@ -139,7 +146,57 @@ const char *ReadRealmName() {
 
 // ----- path resolution -----
 
+// realmList CVar value (the realmlist address, e.g.
+// "logon.turtle-wow.org") — the unambiguous server identity. Unlike the
+// friendly realm name it can't collide across unrelated private servers,
+// so it's the outer key for the shared cache path. Mirrors
+// `Security::CredStore`'s realm scoping.
+const char *ReadRealmList() {
+    using GetRealmList_t = const char *(__fastcall *)(int forceRefresh);
+    return reinterpret_cast<GetRealmList_t>(
+        static_cast<uintptr_t>(Offsets::FUN_CVAR_REALM_LIST))(0);
+}
+
+// Filesystem-safe path component. We create these directories ourselves
+// (WoW doesn't), so any character Windows rejects in a path — or that
+// could surprise, like the space/apostrophe in "N'Zoth" — becomes '_'.
+// Deterministic, so a realm always maps to the same folder.
+std::string SanitizeComponent(const char *s) {
+    std::string out;
+    for (const char *p = s; p != nullptr && *p; ++p) {
+        const char c = *p;
+        const bool safe = (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
+                          (c >= '0' && c <= '9') || c == '.' || c == '-' ||
+                          c == '_';
+        out.push_back(safe ? c : '_');
+    }
+    return out;
+}
+
+// Shared, server-specific cache path:
+//   WTF\ClassicAPI\<realmList>\<realmName>\ClassicAPI_NameCache.txt
+// Not under Account\, so alts on different accounts of the same server
+// share one pool. Empty (defer) until both realmlist + realm are known.
 std::string CachePath() {
+    const char *realmList = ReadRealmList();
+    if (realmList == nullptr || realmList[0] == '\0')
+        return {};
+    const char *realm = ReadRealmName();
+    if (realm == nullptr || realm[0] == '\0')
+        return {};
+    std::string out = "WTF\\ClassicAPI\\";
+    out += SanitizeComponent(realmList);
+    out += '\\';
+    out += SanitizeComponent(realm);
+    out += "\\ClassicAPI_NameCache.txt";
+    return out;
+}
+
+// The pre-shared per-account path, used only to migrate an existing
+// cache into the shared location on first load. Built exactly as it was
+// written (raw account + realm, unsanitized) so it matches the file
+// sitting in WoW's own folders.
+std::string OldCachePath() {
     const char *account = ReadAccountName();
     if (account == nullptr || account[0] == '\0')
         return {};
@@ -154,6 +211,21 @@ std::string CachePath() {
     return out;
 }
 
+// Creates every parent directory of `filePath` (mkdir -p). WoW makes
+// `WTF\` but not `WTF\ClassicAPI\...`, and ofstream won't create
+// directories, so a save into a fresh realm folder would silently fail
+// without this. CreateDirectory on an existing dir no-ops.
+void EnsureParentDirs(const std::string &filePath) {
+    for (size_t pos = 0;;) {
+        const size_t slash = filePath.find('\\', pos);
+        if (slash == std::string::npos)
+            break; // remainder is the filename
+        if (slash > 0)
+            CreateDirectoryA(filePath.substr(0, slash).c_str(), nullptr);
+        pos = slash + 1;
+    }
+}
+
 // ----- account settings (registered with Settings::Account) -----
 
 void SettingsReset() {
@@ -259,21 +331,12 @@ bool Upsert(uint64_t guid, const std::string &name,
     return changed;
 }
 
-void LoadCacheIfNeeded() {
-    if (g_cacheLoaded)
-        return;
-    const std::string path = CachePath();
-    if (path.empty())
-        return; // pre-realm; retry on next call (g_cacheLoaded stays false)
-    g_cacheLoaded = true;
-
-    std::ifstream file(path);
-    if (!file.is_open())
-        return; // first run for this realm
-
-    // v4 format: `name\tguid\tclass\trace\tsex`. Name first since
-    // it's the primary key; GUID is a peripheral field carried for
-    // GUID-keyed lookups. Variable-width hex GUID (no leading zeros).
+// Parses v4 cache lines (`name\tguid\tclass\trace\tsex`) from `file`
+// into the store. Name first since it's the primary key; GUID is a
+// peripheral field carried for GUID-keyed lookups. Variable-width hex
+// GUID (no leading zeros). Shared by the normal load and the one-time
+// migration from the old per-account file.
+void LoadFromStream(std::istream &file) {
     std::string line;
     while (std::getline(file, line)) {
         while (!line.empty() && (line.back() == '\r' || line.back() == '\n'))
@@ -301,10 +364,42 @@ void LoadCacheIfNeeded() {
     }
 }
 
+void LoadCacheIfNeeded() {
+    if (g_cacheLoaded)
+        return;
+    const std::string path = CachePath();
+    if (path.empty())
+        return; // pre-realm; retry on next call (g_cacheLoaded stays false)
+    g_cacheLoaded = true;
+
+    std::ifstream file(path);
+    if (file.is_open()) {
+        LoadFromStream(file);
+        return;
+    }
+
+    // No shared file yet. One-time migration: seed from the old
+    // per-account file if it exists, then mark dirty so the next save
+    // writes the merged data into the shared path. Only when the shared
+    // file is absent — once it exists it's authoritative (a second
+    // account's old-only entries just repopulate via scan / SMSG).
+    const std::string oldPath = OldCachePath();
+    if (oldPath.empty())
+        return;
+    std::ifstream oldFile(oldPath);
+    if (oldFile.is_open()) {
+        LoadFromStream(oldFile);
+        g_dirty = true;
+    }
+}
+
 void SaveCache() {
     const std::string path = CachePath();
     if (path.empty())
         return;
+    // `WTF\ClassicAPI\<realmList>\<realm>\` isn't created by WoW — make
+    // the tree first, else the ofstream open below silently fails.
+    EnsureParentDirs(path);
     const std::string tmp = path + ".tmp";
     {
         std::ofstream out(tmp, std::ios::binary | std::ios::trunc);
@@ -319,7 +414,7 @@ void SaveCache() {
         // sort/scan key when hand-editing. GUID is variable-width
         // hex — 1-8 digits for player GUIDs, up to 16 if a non-player
         // GUID ever lands here.
-        out << "# ClassicAPI name cache v4 (per-realm)\n";
+        out << "# ClassicAPI name cache v4 (per-realm, shared across accounts)\n";
         out << "# name\tguid\tclassID\traceID\tsex\n";
         for (const auto &kv : g_entries) {
             const std::string &name = kv.first;

src/table/Wipe.cpp

@@ -29,6 +29,11 @@ namespace Table::Wipe {
 // guarantee holds in 1.12's Lua 5.0 (`luaH_next` at `0x006FA2A0`),
 // so the pattern ports verbatim.
 //
+// One divergence from the 3.3.5 source: 1.12's Lua 5.0 keeps a table's
+// `table.insert`/`getn` length out of band from its keys (see the
+// `luaL_setn` note below), so after the key-clear loop we must also
+// reset that counter — the 5.1 twipe had no such legacy to clear.
+//
 // Stack discipline matches 3.3.5 to the call:
 //   1. `lua_pushnil(L)`           — initial "no key" sentinel for next
 //   2. `lua_next(L, 1)`           — pops key, pushes (newKey, value)
@@ -51,6 +56,17 @@ static int __fastcall Script_table_wipe(void *L) {
         Game::Lua::RawSet(L, 1);     // t[key] = nil
     }
 
+    // Reset the Lua 5.0 length counter. In 5.0 a table's `table.insert`/
+    // `getn` length is stored OUT of band from its keys (in a `t.n`
+    // field or a weak `sizes[t]` registry entry), so the rawset(nil)
+    // loop above — which only clears keys — leaves it at its old value.
+    // Without this, `table.insert` after a wipe appends at
+    // `getn(t)+1`, past the now-nil slots, and `t[1]` stays nil. 5.1's
+    // wipe doesn't need this (no getn legacy), which is why the ported
+    // logic looked complete. `luaL_setn(L, 1, 0)` puts it back to 0 so
+    // inserts resume at `t[1]`.
+    Game::Lua::SetN(L, 1, 0);
+
     // The table is still at stack[1] and is the result we return.
     Game::Lua::SetTop(L, 1);
     return 1;