From a6ba042cf792d29cda4f7f7924a68a017d9b0335 Mon Sep 17 00:00:00 2001
From: ShadowNinja <shadowninja@minetest.net>
Date: Thu, 5 Jun 2014 12:40:34 -0400
Subject: Add strict module

Also fix leaking globals found by it.
---
 builtin/common/strict.lua | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 builtin/common/strict.lua

(limited to 'builtin/common/strict.lua')

diff --git a/builtin/common/strict.lua b/builtin/common/strict.lua
new file mode 100644
index 000000000..c4b181970
--- /dev/null
+++ b/builtin/common/strict.lua
@@ -0,0 +1,47 @@
+
+-- Always warn when creating a global variable, even outside of a function.
+-- This ignores mod namespaces (variables with the same name as the current mod).
+local WARN_INIT = false
+
+
+local function warn(message)
+	print(os.date("%H:%M:%S: WARNING: ")..message)
+end
+
+
+local meta = {}
+local declared = {}
+
+
+function meta:__newindex(name, value)
+	local info = debug.getinfo(2, "Sl")
+	local desc = ("%s:%d"):format(info.short_src, info.currentline)
+	if not declared[name] then
+		if info.what ~= "main" and info.what ~= "C" then
+			warn(("Assignment to undeclared global %q inside"
+					.." a function at %s.")
+				:format(name, desc))
+		end
+		declared[name] = true
+	end
+	-- Ignore mod namespaces
+	if WARN_INIT and (not core.get_current_modname or
+			name ~= core.get_current_modname()) then
+		warn(("Global variable %q created at %s.")
+			:format(name, desc))
+	end
+	rawset(self, name, value)
+end
+
+
+function meta:__index(name)
+	local info = debug.getinfo(2, "Sl")
+	if not declared[name] and info.what ~= "C" then
+		warn(("Undeclared global variable %q accessed at %s:%s")
+				:format(name, info.short_src, info.currentline))
+	end
+	return rawget(self, name)
+end
+
+setmetatable(_G, meta)
+
-- 
cgit v1.2.3