Dedup trainer craft scans to prevent open freeze

api/core-scan-beasttraining.lua

@@ -705,6 +705,24 @@ MTH_PT_IsPetBookVisible = function()
 	return false
 end
 
+-- Cheap content signature of the trainer's craft rows, so repeated reads of the
+-- same list (multiple CRAFT_UPDATE / open events) don't each pay for a full,
+-- datastore-wide re-scan (that pile-up was freezing the client).
+local MTH_PT_LastScanSignature = nil
+local function MTH_PT_ComputeCraftSignature()
+	local getNumCrafts = MTH_PT_GetGlobal("GetNumCrafts")
+	local getCraftInfo = MTH_PT_GetGlobal("GetCraftInfo")
+	if type(getNumCrafts) ~= "function" or type(getCraftInfo) ~= "function" then return nil end
+	local total = tonumber(getNumCrafts()) or 0
+	if total <= 0 then return nil end
+	local parts = { tostring(total) }
+	for i = 1, total do
+		local name, sub, ctype = getCraftInfo(i)
+		table.insert(parts, tostring(name or "") .. "~" .. tostring(sub or "") .. "~" .. tostring(ctype or ""))
+	end
+	return table.concat(parts, "|")
+end
+
 local function MTH_PT_RunDoubleScan(triggerBase)
 	local triggerText = tostring(triggerBase or "")
 	local feedbackOnOpen = (
@@ -728,9 +746,15 @@ local function MTH_PT_RunDoubleScan(triggerBase)
 		return false
 	end
 
+	local signature = MTH_PT_ComputeCraftSignature()
+	if signature and signature == MTH_PT_LastScanSignature then
+		if MTH_PT_DebugLog then MTH_PT_DebugLog("scan skipped (unchanged signature): trigger=" .. triggerText) end
+		return true
+	end
 	local t0 = time()
 	local ok, added, baselines, ranks = MTH_PT_ApplyScan(triggerText .. ":single")
 	local t1 = time()
+	if ok and signature then MTH_PT_LastScanSignature = signature end
 
 	if MTH_PT_DebugLog then
 		MTH_PT_DebugLog("scan complete: trigger=" .. tostring(triggerBase or "") .. " ok=" .. tostring(ok and true or false) .. " dt=" .. tostring((t1 or 0) - (t0 or 0)) .. "s")
@@ -885,6 +909,10 @@ function MTH_PT_InitService()
 			MTH_PT_RunDoubleScanThrottled("beast-training-rows-present", 8)
 		end
 
+		if (not hasRows) and MTH_PT_TrainingRowsWerePresent then
+			-- Trainer closed: allow one fresh scan the next time it opens.
+			MTH_PT_LastScanSignature = nil
+		end
 		MTH_PT_TrainingRowsWerePresent = hasRows
 		MTH_PT_LastTrainingRowCount = rowCount