UnitNameFromGUID: resolve via object manager + FUN_OBJECT_GET_NAME

The original implementation only consulted the SMSG_NAME_QUERY_RESPONSE-
fed player NameCache, which only populates for GUIDs the engine has
explicitly queried — so currently-synced players (just-targeted, in
view, etc.) typically miss until the engine sends a name query.

Switch to vanilla's own `Script_UnitName` path: resolve the GUID via
`FUN_CLNT_OBJ_MGR_OBJECT_PTR` with TYPEMASK_OBJECT, then call the
engine's polymorphic name getter `FUN_OBJECT_GET_NAME`. That routes
through the player NameCache AND the creature cache, so both player
and NPC GUIDs return real names for any currently-synced unit. Gate
on the "UNKNOWNOBJECT" / "Unknown Being" sentinels so non-unit
objects fall through. Persistent NameCache fallback kept for ex-units
that have left the engine's sync window.

README.md

@@ -45,7 +45,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Map](docs/API.md#map) | `C_Map.GetBestMapForUnit` |
 | [MerchantFrame](docs/API.md#merchantframe) | `C_MerchantFrame.GetBuybackItemID`, `C_MerchantFrame.GetItemInfo`, `C_MerchantFrame.GetNumJunkItems`, `C_MerchantFrame.IsMerchantItemRefundable`, `C_MerchantFrame.IsSellAllJunkEnabled`, `C_MerchantFrame.SellAllJunkItems` |
 | [NamePlate](docs/API.md#nameplate) | `C_NamePlate.GetNamePlateForGUID`, `C_NamePlate.GetNamePlateForUnit`, `C_NamePlate.GetNamePlateGUIDs`, `C_NamePlate.GetNamePlates` |
-| [NameCache](docs/API.md#namecache) | `C_CreatureInfo.GetCreatureID`, `C_PlayerCache.GetPlayerInfoByName`, `C_PlayerCache.IsEnabled`, `C_PlayerCache.IsScanEnabled`, `C_PlayerCache.RememberPlayer`, `C_PlayerCache.SetEnabled`, `C_PlayerCache.SetScanEnabled`, `C_PlayerInfo.GUIDIsCreature`, `C_PlayerInfo.GUIDIsGameObject`, `C_PlayerInfo.GUIDIsPet`, `C_PlayerInfo.GUIDIsPlayer`, `GetPlayerInfoByGUID` |
+| [NameCache](docs/API.md#namecache) | `C_CreatureInfo.GetCreatureID`, `C_PlayerCache.GetPlayerInfoByName`, `C_PlayerCache.IsEnabled`, `C_PlayerCache.IsScanEnabled`, `C_PlayerCache.RememberPlayer`, `C_PlayerCache.SetEnabled`, `C_PlayerCache.SetScanEnabled`, `C_PlayerInfo.GUIDIsCreature`, `C_PlayerInfo.GUIDIsGameObject`, `C_PlayerInfo.GUIDIsPet`, `C_PlayerInfo.GUIDIsPlayer`, `GetPlayerInfoByGUID`, `UnitNameFromGUID` |
 | [Quest](docs/API.md#quest) | `C_QuestLog.GetQuestDetails`, `C_QuestLog.GetQuestIDForLogIndex`, `C_QuestLog.GetTitleForQuestID`, `C_QuestLog.IsOnQuest`, `C_QuestLog.IsQuestDataCachedByID`, `C_QuestLog.IsUnitOnQuest`, `C_QuestLog.RequestLoadQuestByID`, `GetQuestLogLeaderBoardID` |
 | [Spell](docs/API.md#spell) | `C_Spell.CancelSpellByID`, `C_Spell.CastAtCursor`, `C_Spell.DoesSpellExist`, `C_Spell.GetSchoolString`, `C_Spell.GetSpellCooldown`, `C_Spell.GetSpellDescription`, `C_Spell.GetSpellInfo`, `C_Spell.GetSpellLink`, `C_Spell.GetSpellName`, `C_Spell.GetSpellReagents`, `C_Spell.GetSpellSubtext`, `C_Spell.GetSpellTexture`, `C_Spell.IsAutoAttackSpell`, `C_Spell.IsCurrentSpell`, `C_Spell.IsRangedAutoAttackSpell`, `C_Spell.IsSelfBuff`, `C_Spell.IsSpellHarmful`, `C_Spell.IsSpellHelpful`, `C_Spell.IsSpellPassive`, `C_Spell.IsSpellUsable`, `C_Spell.SpellHasRange`, `CancelSpellByName`, `CastSpellNoToggle`, `GetCraftSpellID`, `GetSpellInfo`, `GetSpellLink`, `GetSpellSchool`, `IsHarmfulSpell`, `IsHelpfulSpell`, `IsPassiveSpell`, `IsPlayerSpell`, `IsSpellKnown`, `IsUsableSpell`, `SpellHasRange` |
 | [SpellBook](docs/API.md#spellbook) | `C_SpellBook.GetCurrentLevelSpells`, `C_SpellBook.GetSpellLevelLearned`, `C_SpellBook.GetSpellSkillLine`, `C_SpellBook.IsAutoAttackSpellBookItem`, `C_SpellBook.IsRangedAutoAttackSpellBookItem`, `FindSpellBookSlotByID` |
@@ -54,7 +54,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Talent](docs/API.md#talent) | `GetTalentIDByIndex`, `GetTalentSpellID` |
 | [Time](docs/API.md#time) | `C_DateAndTime.AdjustTimeByDays`, `C_DateAndTime.AdjustTimeByMinutes`, `C_DateAndTime.CompareCalendarTime`, `C_DateAndTime.GetCalendarTimeFromEpoch`, `C_DateAndTime.GetCurrentCalendarTime`, `C_DateAndTime.GetSecondsUntilDailyReset`, `C_DateAndTime.GetServerTimeLocal`, `C_Timer.After`, `C_Timer.NewTicker`, `C_Timer.NewTimer`, `GetServerTime` |
 | [UIColor](docs/API.md#uicolor) | `C_UIColor.GetColors` (backports `GlobalColor.dbc`; companion addon wraps each row with `ColorMixin` and assigns `_G[baseTag]` + `_G[baseTag.."_CODE"]`) |
-| [Unit](docs/API.md#unit) | `GetUnitSpeed`, `UnitClassBase`, `UnitGUID`, `UnitInRange`, `UnitIsAFK`, `UnitIsDND`, `UnitIsFeignDeath`, `UnitIsInMyGuild`, `UnitIsPossessed`, `UnitPower`, `UnitPowerMax`, `UnitPowerType`, `UnitRaceBase`, `UnitStandState`, `UnitTokenFromGUID` |
+| [Unit](docs/API.md#unit) | `GetUnitSpeed`, `UnitClassBase`, `UnitGUID`, `UnitInRange`, `UnitIsAFK`, `UnitIsDND`, `UnitIsFeignDeath`, `UnitIsInMyGuild`, `UnitIsPossessed`, `UnitPower`, `UnitPowerMax`, `UnitPowerType`, `UnitRaceBase`, `UnitStandState`, `UnitSubName`, `UnitTokenFromGUID` |
 | [UnitAuras](docs/API.md#unitauras) | `C_UnitAuras.GetAuraDataByIndex`, `C_UnitAuras.GetAuraDataBySpellName`, `C_UnitAuras.GetAuraDispelTypeColor`, `C_UnitAuras.GetBuffDataByIndex`, `C_UnitAuras.GetDebuffDataByIndex`, `C_UnitAuras.GetPlayerAuraBySpellID`, `C_UnitAuras.GetUnitAuraBySpellID`, `C_UnitAuras.GetUnitAuras` |
 
 ### GlueXML calls

docs/API.md

@@ -249,6 +249,7 @@ build instructions.
 
 - [NameCache](#namecache)
   - [`GetPlayerInfoByGUID(guid)`](#getplayerinfobyguidguid)
+  - [`UnitNameFromGUID(guid)`](#unitnamefromguidguid)
   - [`C_PlayerCache.GetPlayerInfoByName(name)`](#c_playercachegetplayerinfobynamename)
   - [`C_PlayerInfo.GUIDIsPlayer(guid)` / `GUIDIsCreature` / `GUIDIsPet` / `GUIDIsGameObject`](#c_playerinfoguidisplayerguid--guidiscreature--guidispet--guidisgameobject)
   - [`C_CreatureInfo.GetCreatureID(guid)`](#c_creatureinfogetcreatureidguid)
@@ -346,6 +347,7 @@ build instructions.
 - [Unit](#unit)
   - [`UnitGUID(unit)`](#unitguidunit)
   - [`UnitTokenFromGUID(guid)`](#unittokenfromguidguid)
+  - [`UnitSubName(unit)`](#unitsubnameunit)
   - [`GetUnitSpeed(unit)`](#getunitspeedunit)
   - [`UnitClassBase(unit)`](#unitclassbaseunit)
   - [`UnitRaceBase(unit)`](#unitracebaseunit)
@@ -6003,6 +6005,35 @@ instance lives at `0x00C0E228`; entry layout (name, realm, race,
 sex, class) was reverse-engineered from the
 `SMSG_NAME_QUERY_RESPONSE` write path at `0x0055F310`.
 
+### `UnitNameFromGUID(guid)`
+
+Returns `name, realm` for the player identified by `guid`, or `nil`
+if no player with that GUID has been encountered yet. Same lookup
+chain as [`GetPlayerInfoByGUID`](#getplayerinfobyguidguid) (engine
+NameCache, persistent on-disk fallback when enabled) — just narrower
+return shape for callers that only need the name.
+
+```lua
+local name, realm = UnitNameFromGUID(UnitGUID("target"))
+if name then
+    ChatFrame1:AddMessage("Target: " .. name)
+end
+
+-- Resolving a chat link
+local name, realm = UnitNameFromGUID("0x0000000000000777")
+```
+
+`realm` is always `""` in vanilla — the engine doesn't populate
+per-player realm names and 1.12 has no cross-realm interaction.
+We push the empty string rather than `nil` to match the convention
+of the other player-info accessors; addons can gate on `realm == ""`.
+
+Doesn't trigger a network query on miss. To populate an unknown
+GUID, either let the engine receive a `SMSG_NAME_QUERY_RESPONSE`
+through normal chat/target interaction, or call
+[`C_PlayerCache.RememberPlayer`](#c_playercacherememberplayerguid-name-classtoken)
+explicitly.
+
 ### `C_PlayerCache.GetPlayerInfoByName(name)`
 
 Returns
@@ -8251,6 +8282,33 @@ end
 > ex-targets, ex-mouseover units, distant players seen in the chat
 > log, etc. The engine simply doesn't address those by token.
 
+### `UnitSubName(unit)`
+
+Returns the NPC's subtitle / title string (the small italic text
+under their name in the tooltip): `"Innkeeper"`, `"Stable Master"`,
+`"<Master Engineer>"`, etc. Returns `nil` for players, unsynced
+NPCs, and NPCs with no subtitle.
+
+```lua
+/dump UnitSubName("target")
+-- "Innkeeper"             (Stormwind innkeep)
+-- "<Auction House>"       (auctioneer)
+-- nil                     (a player, or a wolf in the woods)
+```
+
+Modern WoW returns the subtitle as `UnitName`'s second return;
+vanilla 1.12's `UnitName` returns only one value, leaving no
+direct route to the subtitle. Addons that wanted it had to scrape
+`GameTooltip` text, which is fragile and required the unit to be
+hovered. `UnitSubName` reads it straight off the engine's creature
+cache (`[unit + 0xB30] → [+0x10]`), no tooltip round-trip.
+
+Coverage caveat: the creature cache row is populated when an NPC
+becomes visible to the client AND the server has sent its
+`CMSG_CREATURE_QUERY_RESPONSE`. The first time a fresh NPC appears
+the row may be briefly NULL — usually only one or two frames.
+Subsequent calls succeed once the response lands.
+
 ### `GetUnitSpeed(unit)`
 
 Returns `currentSpeed, runSpeed, flightSpeed, swimSpeed` — all four

src/Offsets.h

@@ -405,6 +405,23 @@ enum Offsets {
     // descriptor at +0x114 — these are sibling classes under CGObject
     // with class-specific descriptor offsets.
     OFF_UNIT_DESCRIPTOR = 0x110,
+
+    // CGCreature client-side creature-data cache row. Populated by the
+    // engine when an NPC GUID becomes visible (the same row the
+    // `CreatureCache` SMSG fills with the templated NPC's name,
+    // subname, etc.). NULL for unsynced units or for player CGUnits
+    // (players don't have a row in this cache — their name comes from
+    // the SMSG_NAME_QUERY_RESPONSE-fed name cache at `0x00C0E228`).
+    //
+    // Layout of the cache row:
+    //   +0x00  ?
+    //   +0x0C  name C-string ptr (alias of UNIT_NAME for creatures)
+    //   +0x10  subName C-string ptr  ("Innkeeper", "<Master Trainer>", etc.)
+    //
+    // Used by `Script_UnitName`'s creature path and by VanillaMinimapTracking's
+    // subname-based blip filter (`src/Blips.cpp::ExtractUnitSubName`).
+    OFF_UNIT_CREATURE_CACHE_ROW = 0xB30,
+    OFF_CREATURE_CACHE_SUB_NAME = 0x10,
     // Pointer to the CGUnit's 8-byte GUID at `*(CGUnit + 0x08)`. Verified
     // in `Script_GetInventoryItemLink` at `0x004C8CB0`-`0x004C8CB5`:
     // `mov eax, [esi+8]; mov edi, [eax]; mov ecx, [eax+4]` reads the

src/player/Info.cpp

@@ -41,6 +41,7 @@
 #include "guid/Guid.h"
 
 #include <cstdint>
+#include <cstring>
 
 namespace Player::Info {
 
@@ -182,6 +183,92 @@ int PushFromNameCacheEntry(void *L, const char *name,
     return 7;
 }
 
+// `UnitNameFromGUID(guid)` → `(name, realm)`. Modern WoW backport;
+// vanilla 1.12 doesn't expose any GUID → name accessor at the Lua
+// surface, so addons that need to resolve a chat link or combat-log
+// GUID can't get a name without round-tripping through a unit token.
+//
+// Resolution order (matches vanilla's own `Script_UnitName` at
+// `0x00517020`):
+//   1. Resolve the GUID through the object manager. Any currently-
+//      synced unit — player you can see, NPC in interact range,
+//      target / mouseover / party / raid member — gets a `CGObject *`
+//      back. Call the engine's canonical polymorphic name getter
+//      `FUN_OBJECT_GET_NAME` on it; this routes through the player
+//      NameCache for players AND the creature cache for NPCs, so it
+//      works for both with a single call.
+//   2. If the unit isn't currently synced (ex-target who logged off,
+//      player encountered earlier in chat but no longer visible),
+//      fall back to the persistent NameCache (when enabled).
+//
+// `realm` is always `""` in vanilla — the engine doesn't populate
+// per-player realm names and 1.12 has no cross-realm interaction.
+// We push the empty string rather than nil so callers don't have to
+// special-case the second return; modern WoW returns nil, but
+// `realm == ""` is just as easy to gate on.
+//
+// Returns nothing on:
+//   - Missing or non-string arg (raises an error rather than return).
+//   - Unparseable GUID string.
+//   - Zero / NULL GUID.
+//   - GUID not resolvable in the object manager AND not in persistent
+//     NameCache (i.e., we've never seen this unit).
+//
+// Doesn't trigger a network query on miss — passive read, same as
+// `GetPlayerInfoByGUID`. Use `C_PlayerCache.RememberPlayer` or let
+// the engine populate via normal interaction.
+int __fastcall Script_UnitNameFromGUID(void *L) {
+    if (!Game::Lua::IsString(L, 1)) {
+        Game::Lua::Error(L, "Usage: UnitNameFromGUID(\"0x...\")");
+        return 0;
+    }
+    const char *guidStr = Game::Lua::ToString(L, 1);
+    uint32_t hi, lo;
+    if (!ParseGUID(guidStr, hi, lo))
+        return 0;
+    if (hi == 0 && lo == 0)
+        return 0;
+
+    // Object-manager path — TYPEMASK_OBJECT (0x01) is permissive; the
+    // name getter at `FUN_OBJECT_GET_NAME` does its own type check and
+    // safely returns the "UNKNOWNOBJECT" sentinel for non-unit
+    // objects (gameobjects etc.), so we just gate on the sentinel
+    // rather than pre-filtering by typemask.
+    using ObjectPtr_t = void *(__fastcall *)(uint32_t typeMask,
+                                              const char *debugMsg,
+                                              uint32_t guidLo,
+                                              uint32_t guidHi,
+                                              int debugCode);
+    using GetName_t = const char *(__thiscall *)(void *obj, int *outFlags);
+
+    auto objectPtr = reinterpret_cast<ObjectPtr_t>(
+        Offsets::FUN_CLNT_OBJ_MGR_OBJECT_PTR);
+    void *obj = objectPtr(Offsets::TYPEMASK_OBJECT, nullptr, lo, hi, 0);
+    if (obj != nullptr) {
+        auto getName = reinterpret_cast<GetName_t>(Offsets::FUN_OBJECT_GET_NAME);
+        const char *name = getName(obj, nullptr);
+        if (name != nullptr && *name != '\0' &&
+            std::strcmp(name, "UNKNOWNOBJECT") != 0 &&
+            std::strcmp(name, "Unknown Being") != 0) {
+            Game::Lua::PushString(L, name);
+            Game::Lua::PushString(L, "");
+            return 2;
+        }
+    }
+
+    // Object-manager miss / sentinel — fall back to the persistent
+    // NameCache (when enabled). Covers ex-units no longer in the
+    // engine's sync window.
+    const std::string *cachedName = nullptr;
+    const NameCache::Entry *cached = NameCache::Lookup(
+        (static_cast<uint64_t>(hi) << 32) | lo, &cachedName);
+    if (cached == nullptr || cachedName == nullptr || cachedName->empty())
+        return 0;
+    Game::Lua::PushString(L, cachedName->c_str());
+    Game::Lua::PushString(L, "");
+    return 2;
+}
+
 // `C_PlayerCache.GetPlayerInfoByName(name)` — name-keyed lookup over
 // the persistent NameCache. Returns `(localizedClass, englishClass,
 // localizedRace, englishRace, sex, name, realm, guid)` or nothing if
@@ -212,6 +299,8 @@ int __fastcall Script_C_PlayerCache_GetPlayerInfoByName(void *L) {
 static void RegisterLuaFunctions() {
     Game::Lua::RegisterGlobalFunction("GetPlayerInfoByGUID",
                                        &Script_GetPlayerInfoByGUID);
+    Game::Lua::RegisterGlobalFunction("UnitNameFromGUID",
+                                       &Script_UnitNameFromGUID);
     Game::Lua::RegisterTableFunction("C_PlayerCache", "GetPlayerInfoByName",
                                      &Script_C_PlayerCache_GetPlayerInfoByName);
 }

src/unit/SubName.cpp

@@ -0,0 +1,85 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU Lesser 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// `UnitSubName(unit)` — returns the NPC's subname / title (the small
+// italic text under their name in the tooltip): "Innkeeper",
+// "Stable Master", "<Master Engineer>", etc. Modern WoW exposes this
+// via `UnitName`'s second return; vanilla 1.12's `UnitName` returns
+// only one value, so addons that want the subtitle have to roll their
+// own — until now.
+//
+// Returns `nil` for:
+//   - Unresolvable unit token (`target` with nothing targeted, empty
+//     `partyN` slot, etc.).
+//   - Player units — they don't have a row in the creature cache.
+//   - NPCs whose creature data hasn't synced yet (rare; happens when
+//     the unit comes into view but the SMSG_CREATURE_QUERY_RESPONSE
+//     hasn't arrived).
+//   - NPCs with no subname (most non-vendor / non-trainer creatures).
+//
+// Raises a Lua error on missing / non-string `unit` argument — same
+// semantics as the engine's `UnitName`.
+//
+// Implementation: walks the creature cache row at `[unit + 0xB30]` →
+// `[+0x10]` (subname C string). Verified path; same one
+// VanillaMinimapTracking's blip subname filter uses.
+
+#include "Game.h"
+#include "Offsets.h"
+
+#include <cstdint>
+
+namespace Unit::SubName {
+
+namespace {
+
+using ResolveUnitToken_t = void *(__fastcall *)(const char *token);
+
+int __fastcall Script_UnitSubName(void *L) {
+    if (!Game::Lua::IsString(L, 1)) {
+        Game::Lua::Error(L, "Usage: UnitSubName(\"unit\")");
+        return 0;
+    }
+    const char *token = Game::Lua::ToString(L, 1);
+    if (token == nullptr)
+        return 0;
+
+    auto resolve = reinterpret_cast<ResolveUnitToken_t>(
+        Offsets::FUN_RESOLVE_UNIT_TOKEN);
+    auto *unit = static_cast<const uint8_t *>(resolve(token));
+    if (unit == nullptr)
+        return 0;
+
+    auto *cacheRow = *reinterpret_cast<const uint8_t *const *>(
+        unit + Offsets::OFF_UNIT_CREATURE_CACHE_ROW);
+    if (cacheRow == nullptr)
+        return 0;
+
+    auto *subName = *reinterpret_cast<const char *const *>(
+        cacheRow + Offsets::OFF_CREATURE_CACHE_SUB_NAME);
+    if (subName == nullptr || *subName == '\0')
+        return 0;
+
+    Game::Lua::PushString(L, subName);
+    return 1;
+}
+
+void RegisterLuaFunctions() {
+    Game::Lua::RegisterGlobalFunction("UnitSubName", &Script_UnitSubName);
+}
+
+const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace
+
+} // namespace Unit::SubName