[BUG FIX] Fix regressions which made it nearly impossible to obfuscate scripts without using LuaJIT.

src/prometheus.lua

@@ -39,6 +39,17 @@ end) then
     end
 end
 
+if not math.log10 then
+    local ln10 = math.log(10);
+    math.log10 = function(x)
+        return math.log(x) / ln10;
+    end
+end
+
+if not loadstring then
+    loadstring = load
+end
+
 -- newproxy polyfill
 _G.newproxy = _G.newproxy or function(arg)
     if arg then

src/prometheus/steps/NumbersToExpressions.lua

@@ -14,6 +14,8 @@ local visitast = require("prometheus.visitast")
 local util = require("prometheus.util")
 local logger = require("logger")
 local AstKind = Ast.AstKind
+local SAFE_INT_LIMIT = jit and math.huge or 2^53
+local MAX_VAL = jit and math.huge or 2^54
 
 local NumbersToExpressions = Step:extend()
 NumbersToExpressions.Description = "This Step Converts number Literals to Expressions"
@@ -37,6 +39,9 @@ NumbersToExpressions.SettingsDescriptor = {
 	NumberRepresentationMutation = {
 		type = "boolean",
 		default = false,
+
+		-- NOTE: This alias is a legacy misspelling preservation.
+		-- Please don't remove it.
 		aliases = { "NumberRepresentationMutaton" },
 	},
 
@@ -92,7 +97,9 @@ function NumbersToExpressions:init(_)
 		end,
 
 		function(val, depth) -- Modulo
+			if val > MAX_VAL then return false end
 			local lhs, rhs = generateModuloExpression(val)
+			if lhs > SAFE_INT_LIMIT or rhs > SAFE_INT_LIMIT then return false end
 			if tonumber(tostring(lhs)) % tonumber(tostring(rhs)) ~= val then
 				return false
 			end
@@ -153,7 +160,30 @@ function NumbersToExpressions:CreateNumberExpression(val, depth)
 
 			local exp = math.floor(math.log10(math.abs(val)))
 			local mantissa = val / (10 ^ exp)
-			return Ast.NumberExpression(string.format("%.15ge%d", mantissa, exp))
+
+			-- LuaJIT has full double precision support. Meaning we don't need aggressive safety harnesses for LuaJIT.
+			if jit then
+				return Ast.NumberExpression(string.format("%.15ge%d", mantissa, exp))
+			end
+
+			local formatStr = string.format("%ge%+d", mantissa, exp)
+			local concatStr = mantissa .. "e" .. (exp >= 0 and "+" or "") .. exp
+
+			local formatVal = loadstring("return " .. formatStr)
+			local concatVal = loadstring("return " .. concatStr)
+
+			local formatResult = formatVal and formatVal()
+			local concatResult = concatVal and concatVal()
+
+			local formatErr = formatResult and math.abs(formatResult - val) or math.huge
+			local concatErr = concatResult and math.abs(concatResult - val) or math.huge
+
+			if formatErr > 0 and concatErr > 0 then
+				return Ast.NumberExpression(val)
+			end
+
+			local useFormat = formatErr <= concatErr
+			return Ast.NumberExpression(useFormat and formatStr or concatStr)
 		end
 
 		if format == "normal" then
@@ -185,4 +215,4 @@ function NumbersToExpressions:apply(ast)
 	end)
 end
 
-return NumbersToExpressions
+return NumbersToExpressions

tests/strings-integrity.lua

@@ -0,0 +1,26 @@
+--============================================================
+-- Strings Integrity Test Suite
+-- Target: NumbersToExpressions Step
+-- Author: SpinnySpiwal
+-- Purpose: Prevent any further quality regressions from NumbersToExpressions.
+-- There was no actual bugs per se, but the bug was the use of Vanilla Lua instead of LuaJIT.
+-- This test ensures that the obfuscator stays client-agnostic & doesn't require a specific Lua version.
+--============================================================
+local integrity = {}
+for i = 0, 255 do integrity[i+1]=i end
+assert(#integrity == 256, "Failed to create integrity array! Reason: array length is not 256!")
+local array = {}
+
+local function chararray(str)
+	for i = 1, #str do
+		array[i] = string.byte(str:sub(i, i))
+	end
+	return array
+end
+
+local cArray = chararray("\0\1\2\3\4\5\6\7\8\9\10\11\12\13\14\15\16\17\18\19\20\21\22\23\24\25\26\27\28\29\30\31\32\33\34\35\36\37\38\39\40\41\42\43\44\45\46\47\48\49\50\51\52\53\54\55\56\57\58\59\60\61\62\63\64\65\66\67\68\69\70\71\72\73\74\75\76\77\78\79\80\81\82\83\84\85\86\87\88\89\90\91\92\93\94\95\96\97\98\99\100\101\102\103\104\105\106\107\108\109\110\111\112\113\114\115\116\117\118\119\120\121\122\123\124\125\126\127\128\129\130\131\132\133\134\135\136\137\138\139\140\141\142\143\144\145\146\147\148\149\150\151\152\153\154\155\156\157\158\159\160\161\162\163\164\165\166\167\168\169\170\171\172\173\174\175\176\177\178\179\180\181\182\183\184\185\186\187\188\189\190\191\192\193\194\195\196\197\198\199\200\201\202\203\204\205\206\207\208\209\210\211\212\213\214\215\216\217\218\219\220\221\222\223\224\225\226\227\228\229\230\231\232\233\234\235\236\237\238\239\240\241\242\243\244\245\246\247\248\249\250\251\252\253\254\255")
+for i = 1, #cArray do
+	if cArray[i] ~= integrity[i] then
+		error("Integrity check failed!")
+	end
+end