fix ThemePrefs

The ThemePrefs table contains several functions and single standalone variable, NeedsSaving.  When a themer calls ThemePrefs.Save() the system will check the status of NeedsSaved to determine whether it really needs to save or not.  This is by design to prevent unnecessary writing to disk.

As far as I am able to discern, NeedsSaved would never be anything but false due to scoping within the ThemePrefs table.  This commit properly scopes that variable as it used within the functions.

It looks like ThemePrefs.ForceSave() was added as a workaround; it didn't check the status of NeedsSaved and just always saved, "no matter what."  Though it seems safe to outright remove ForceSave(), I'm leaving it in for compatibility.  Consider it deprecated I suppose.

Themes/_fallback/Scripts/02 ThemePrefs.lua

@@ -79,6 +79,7 @@ ThemePrefs =
 	-- Only read from disk once, when _fallback calls this; we just
 	-- need the base set once to add prefs onto.
 	Init = function( prefs, bLoadFromDisk )
+
 		-- If we don't have IniFile, we can't read/write from/to disk
 		if not IniFile then Warn( GetString("IniFileMissing") ) end
 
@@ -99,7 +100,7 @@ ThemePrefs =
 
 		-- if the key doesn't exist, add it with our default value
 		for k, tbl in pairs(prefs) do
-			if not PrefsTable[section][k] then
+			if PrefsTable[section][k] == nil then
 				Trace( k .. " doesn't exist, creating" )
 				PrefsTable[section][k] = tbl.Default
 			end
@@ -116,16 +117,17 @@ ThemePrefs =
 
 	Save = function()
 --		Trace( "ThemePrefs.Save" )
-		if not IniFile then return false end
-		if not NeedsSaved then return end
-		NeedsSaved = false
-		IniFile.WriteFile( ThemePrefsPath, PrefsTable )
+		if IniFile and ThemePrefs.NeedsSaved then
+			IniFile.WriteFile( ThemePrefsPath, PrefsTable )
+			ThemePrefs.NeedsSaved = false
+			return
+		end
 	end,
 
 	-- for when you absolutely have to save, no matter what NeedsSaved says.
 	ForceSave = function()
 		if not IniFile then return false end
-		NeedsSaved = false
+		ThemePrefs.NeedsSaved = false
 		IniFile.WriteFile( ThemePrefsPath, PrefsTable )
 	end,
 
@@ -140,7 +142,11 @@ ThemePrefs =
 	Set = function( name, value )
 		--Trace( ("ThemePrefs.Set(%s, %s)"):format(name, tostring(value)) )
 		local tbl = ResolveTable(name)
-		if tbl then tbl[name] = value; NeedsSaved = true; return end
+		if tbl then
+			ThemePrefs.NeedsSaved = true
+			tbl[name] = value
+			return
+		end
 		Warn( "Set: "..GetString("UnknownPreference"):format(name) )
 	end,
 };