fix Lua 5.4 CLI loadstring crashes

Author: levno-710

src/cli.lua

@@ -45,6 +45,21 @@ local function lines_from(file)
 	return lines
 end
 
+local function load_chunk(content, chunkName, environment)
+	if _VERSION == "Lua 5.1" then
+		local func, err = loadstring(content, chunkName)
+		if not func then
+			return nil, err
+		end
+		if environment then
+			setfenv(func, environment)
+		end
+		return func
+	end
+
+	return load(content, chunkName, "t", environment)
+end
+
 -- CLI
 local config, sourceFile, outFile, luaVersion, prettyPrint
 
@@ -76,9 +91,10 @@ while i <= #arg do
 
 			local content = table.concat(lines_from(filename), "\n")
 			-- Load Config from File
-			local func = loadstring(content)
-			-- Sandboxing
-			setfenv(func, {})
+			local func, err = load_chunk(content, "@" .. filename, {})
+			if not func then
+				Prometheus.Logger:error(string.format('Failed to parse config file "%s": %s', filename, tostring(err)))
+			end
 			config = func()
 		elseif curr == "--out" or curr == "--o" then
 			i = i + 1

src/prometheus/compiler/expressions/boolean.lua

@@ -5,6 +5,25 @@
 -- This Script contains the expression handler for the BooleanExpression.
 
 local Ast = require("prometheus.ast");
+
+local expressionEvaluators = {
+    [Ast.GreaterThanExpression] = function(left, right)
+        return left > right
+    end,
+    [Ast.LessThanExpression] = function(left, right)
+        return left < right
+    end,
+    [Ast.GreaterThanOrEqualsExpression] = function(left, right)
+        return left >= right
+    end,
+    [Ast.LessThanOrEqualsExpression] = function(left, right)
+        return left <= right
+    end,
+    [Ast.NotEqualsExpression] = function(left, right)
+        return left ~= right
+    end,
+}
+
 local function createRandomASTCFlowExpression(resultBool)
     local expTB = {
         Ast.GreaterThanExpression,
@@ -14,21 +33,12 @@ local function createRandomASTCFlowExpression(resultBool)
         Ast.NotEqualsExpression
     }
 
-    local expLookup = {
-        [Ast.GreaterThanExpression] = ">";
-        [Ast.LessThanExpression] = "<";
-        [Ast.GreaterThanOrEqualsExpression] = ">=";
-        [Ast.LessThanOrEqualsExpression] = "<=";
-        [Ast.NotEqualsExpression] = "~=";
-    }
-
-    local leftInt, rightInt, boolResult, r3, randomExp
+    local leftInt, rightInt, boolResult, randomExp
     repeat
         randomExp = expTB[math.random(1, #expTB)]
         leftInt = Ast.NumberExpression(math.random(1, 2^24))
         rightInt = Ast.NumberExpression(math.random(1, 2^24))
-        r3 = "return " .. leftInt.value .. expLookup[randomExp] .. rightInt.value
-        boolResult = loadstring(r3)()
+        boolResult = expressionEvaluators[randomExp](leftInt.value, rightInt.value)
     until boolResult == resultBool
 
     return randomExp(leftInt, rightInt, false)
@@ -47,4 +57,3 @@ return function(self, expression, _, numReturns)
     end
     return regs;
 end;
-