Attach debugger on nil return value

debugger.lua

@@ -0,0 +1,27 @@
+local function execDebug()
+  local input = io.input()
+  local result = { pcall(input.read, input, "*l") }
+  if not result[1] then
+    return false, result[2]
+  end
+
+  local func = load("return " .. result[2])
+  if type(func) ~= "function" then
+    return false, func
+  end
+
+  return pcall(func)
+end
+
+local function debugREPL(onResult)
+  local result, retval
+  repeat
+    result, retval = execDebug()
+    if result and type(onResult) == "function" then
+      onResult(retval)
+    end
+  until not result
+  return retval
+end
+
+return { debugREPL = debugREPL, execDebug = execDebug }

storage/itemstack.lua

@@ -2,6 +2,7 @@ local Inventory = require("storage.inventory")
 local Sentinel = require("storage.sentinel")
 local Logging = require("logging")
 local Logger = Logging.getGlobalLogger()
+local Debugger = require("debugger")
 
 local ItemStack = Sentinel:tag({}, Sentinel.ITEMSTACK)
 ItemStack.__index = ItemStack
@@ -199,7 +200,12 @@ function ItemStack:transferTo(target, count)
     return count == 0, 0
   end
 
-  local result = { pcall(self:getInventory().pushItems, peripheral.getName(target:getInventory()), self:getSlot(), cap, target:getSlot()) }
+  local errC = 0
+  local result
+  repeat
+    result = { pcall(self:getInventory().pushItems, peripheral.getName(target:getInventory()), self:getSlot(), cap, target:getSlot()) }
+    errC = errC + 1
+  until (not result[1]) or (result[2] ~= nil) or (errC > 8)
 
   if not result[1] then
     return false, result[2]
@@ -207,13 +213,19 @@ function ItemStack:transferTo(target, count)
 
   if result[2] == nil then
     Logger:error(
-      "Error transferring item", self:getInventory().pushItems, Logger.plain("\n"),
+      "Error transferring item", self:getInventory().pushItems, "\n",
-      peripheral.getName(target:getInventory()), Logger.plain("\n"),
+      peripheral.getName(target:getInventory()), "\n",
-      cap, Logger.plain("\n"),
+      errC, "\n",
-      self, Logger.plain("\n"),
+      cap, "\n",
-      target, Logger.plain("\n"),
+      self, "\n",
+      target, "\n",
+      target:getInventory().getItemLimit(target:getSlot()), "\n",
       result
     )
+    local errorCond = Debugger.debugREPL(function(retval)
+      Logger:error("->", retval)
+    end)
+    Logger:error("x>", errorCond)
   end
 
   target:_modify(result[2], self)