test-leaks: Fix with Lua 5.1

I have no idea why this needs collectgarbage() to be called twice.

On the other hand, I can explain the change in tooltip.lua. Lua 5.2 introduced
"ephermeron tables". This means that in the following sitation, lua 5.2 can
collect the entry from the table, while 5.1 keeps the entry alive, because the
table has a strong reference to the value and that in turn has a strong
reference to the key:

  t = setmetatable({}, { __mode = "k"})
  do
    local k = {}
    t[k] = function() print(k) end
  end
  collectgarbage("collect")
  print(next(t, nil))

To handle this incompatibility, this commit just removes the whole indirection
through the module-level variable "data".

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/awful/tooltip.lua

@@ -59,17 +59,6 @@ local ipairs = ipairs
 -- @tfield boolean visible True if tooltip is visible.
 local tooltip = { mt = {}  }
 
---- Tooltip private data.
--- @local
--- @table tooltip.data
--- @tfield string fg tooltip foreground color.
--- @tfield string font Tooltip font.
--- @tfield function hide The hide() function.
--- @tfield function show The show() function.
--- @tfield gears.timer timer The text update timer.
--- @tfield function timer_function The text update timer function.
-local data = setmetatable({}, { __mode = 'k' })
-
 -- Place the tooltip on the screen.
 -- @tparam tooltip self A tooltip object.
 local function place(self)
@@ -98,10 +87,10 @@ end
 local function show(self)
     -- do nothing if the tooltip is already shown
     if self.visible then return end
-    if data[self].timer then
-        if not data[self].timer.started then
-            data[self].timer_function()
-            data[self].timer:start()
+    if self.timer then
+        if not self.timer.started then
+            self.timer_function()
+            self.timer:start()
         end
     end
     set_geometry(self)
@@ -116,9 +105,9 @@ end
 local function hide(self)
     -- do nothing if the tooltip is already hidden
     if not self.visible then return end
-    if data[self].timer then
-        if data[self].timer.started then
-            data[self].timer:stop()
+    if self.timer then
+        if self.timer.started then
+            self.timer:stop()
         end
     end
     self.visible = false
@@ -154,8 +143,8 @@ end
 -- @tparam tooltip self A tooltip object.
 -- @tparam number timeout The timeout value.
 tooltip.set_timeout = function(self, timeout)
-    if data[self].timer then
-        data[self].timer.timeout = timeout
+    if self.timer then
+        self.timer.timeout = timeout
     end
 end
 
@@ -165,8 +154,8 @@ end
 -- @tparam gears.object object An object with `mouse::enter` and
 --   `mouse::leave` signals.
 tooltip.add_to_object = function(self, object)
-    object:connect_signal("mouse::enter", data[self].show)
-    object:connect_signal("mouse::leave", data[self].hide)
+    object:connect_signal("mouse::enter", self.show)
+    object:connect_signal("mouse::leave", self.hide)
 end
 
 --- Remove tooltip from an object.
@@ -175,8 +164,8 @@ end
 -- @tparam gears.object object An object with `mouse::enter` and
 --   `mouse::leave` signals.
 tooltip.remove_from_object = function(self, object)
-    object:disconnect_signal("mouse::enter", data[self].show)
-    object:disconnect_signal("mouse::leave", data[self].hide)
+    object:disconnect_signal("mouse::enter", self.show)
+    object:disconnect_signal("mouse::leave", self.hide)
 end
 
 
@@ -213,24 +202,24 @@ tooltip.new = function(args)
             delay_timeout:stop()
         end)
 
-        data[self] = {
-            show = function()
+        function self.show()
             if not delay_timeout.started then
                 delay_timeout:start()
             end
-            end,
-            hide = function()
+        end
+        function self.hide()
             if delay_timeout.started then
                 delay_timeout:stop()
             end
             hide(self)
-            end,
-        }
+        end
     else
-        data[self] = {
-            show = function() show(self) end,
-            hide = function() hide(self) end,
-        }
+        function self.show()
+            show(self)
+        end
+        function self.hide()
+            hide(self)
+        end
     end
 
     -- export functions
@@ -242,11 +231,11 @@ tooltip.new = function(args)
 
     -- setup the timer action only if needed
     if args.timer_function then
-        data[self].timer = timer { timeout = args.timeout and args.timeout or 1 }
-        data[self].timer_function = function()
+        self.timer = timer { timeout = args.timeout and args.timeout or 1 }
+        self.timer_function = function()
                 self:set_markup(args.timer_function())
             end
-        data[self].timer:connect_signal("timeout", data[self].timer_function)
+        self.timer:connect_signal("timeout", self.timer_function)
     end
 
     -- Set default properties
@@ -274,7 +263,7 @@ tooltip.new = function(args)
 
     -- Close the tooltip when clicking it.  This gets done on release, to not
     -- emit the release event on an underlying object, e.g. the titlebar icon.
-    self.wibox:buttons(abutton({}, 1, nil, function() data[self].hide() end))
+    self.wibox:buttons(abutton({}, 1, nil, function() self.hide() end))
 
     -- Re-place when the geometry of the wibox changes.
     self.wibox:connect_signal("property::width",  function() place(self) end)

tests/test-leaks.lua

@@ -29,6 +29,7 @@ local function collectable(a, b, c, d, e, f, g, h, last)
         prepare_for_collect = nil
     end
     collectgarbage("collect")
+    collectgarbage("collect")
     -- Check if the table is now empty
     for k, v in pairs(objs) do
         print("Some object was not garbage collected!")