error handling

sys/apps/shell

@@ -516,6 +516,7 @@ local function autocomplete(line)
 			for _,sItem in pairs(results) do
 				nMaxLen = math.max(string.len(sItem) + 1, nMaxLen)
 			end
+			local w = term.getSize()
 			local nCols = math.floor(w / nMaxLen)
 			if #tDirs < nCols then
 				for _ = #tDirs + 1, nCols do

sys/network/peripheral.lua

@@ -69,7 +69,11 @@ Event.addRoutine(function()
 							break
 						end
 						if peripheral[data.fn] then
+							-- need to trigger an error on the other end
+							-- local s, m = pcall()
 							socket:write({ peripheral[data.fn](table.unpack(data.args)) })
+						else
+							socket:write({ false, "Invalid function: " .. data.fn })
 						end
 					end
 

sys/network/proxy.lua

@@ -13,6 +13,11 @@ Event.addRoutine(function()
 			if api then
 				local proxy = _G[api]
 
+				if not proxy then
+					print('proxy: invalid API')
+					return
+				end
+
 				local methods = { }
 				for k,v in pairs(proxy) do
 					if type(v) == 'function' then