notification: Make the position index more robust.

If the notification screen or position changed, it would end up in the
wrong index and removing it would fail. This cannot happen anymore.

lib/naughty/core.lua

@@ -165,6 +165,35 @@ capi.screen.connect_signal("removed", function(scr)
     naughty.notifications[scr] = nil
 end)
 
+local function get_screen(s)
+    return s and capi.screen[s]
+end
+
+local function remove_from_index(n)
+    for _, positions in pairs(naughty.notifications) do
+        for _, ns in pairs(positions) do
+            for k, n2 in ipairs(ns) do
+                if n2 == n then
+                    table.remove(ns, k)
+                    return
+                end
+            end
+        end
+    end
+end
+
+-- When id or screen are set after the object is created, update the indexing.
+local function update_index(n)
+    -- Find the only index and remove it (there's an useless loop, but it's small).
+    remove_from_index(n)
+
+    -- Add to the index again
+    local s = get_screen(n.screen or n.preset.screen or screen.focused())
+    naughty.notifications[s] = naughty.notifications[s] or {}
+    table.insert(naughty.notifications[s][n.position], n)
+end
+
+
 --- Notification state.
 --
 -- This function is deprecated, use `naughty.suspended`.
@@ -406,7 +435,7 @@ local function cleanup(self, reason)
     local scr = self.screen
 
     assert(naughty.notifications[scr][self.position][self.idx] == self)
-    table.remove(naughty.notifications[scr][self.position], self.idx)
+    remove_from_index(self)
 
     -- Update all indices
     for k, n in ipairs(naughty.notifications[scr][self.position]) do
@@ -433,10 +462,6 @@ end
 
 naughty.connect_signal("destroyed", cleanup)
 
-local function get_screen(s)
-    return s and capi.screen[s]
-end
-
 -- Proxy the global suspension state on all notification objects
 local function get_suspended(self)
     return properties.suspended and not self.ignore_suspend
@@ -482,7 +507,6 @@ end
 
 -- Register a new notification object.
 local function register(notification, args)
-
     -- Add the some more properties
     rawset(notification, "get_suspended", get_suspended)
 
@@ -611,6 +635,9 @@ function naughty.notify(args)
     return nnotif(args)
 end
 
+naughty.connect_signal("property::screen"  , update_index)
+naughty.connect_signal("property::position", update_index)
+
 return setmetatable(naughty, {__index = index_miss, __newindex = set_index_miss})
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/naughty/layout/legacy.lua

@@ -266,14 +266,27 @@ local function set_escaped_text(self)
     if self.size_info then update_size(self) end
 end
 
+local function seek_and_destroy(n)
+    for _, positions in pairs(current_notifications) do
+         for _, pos in pairs(positions) do
+            for k, n2 in ipairs(pos) do
+                if n == n2 then
+                    table.remove(pos, k)
+                    return
+                end
+            end
+         end
+    end
+end
+
 local function cleanup(self, _ --[[reason]], keep_visible)
     -- It is not a legacy notification
     if not self.box then return end
 
     local scr = self.screen
 
-    assert(current_notifications[scr][self.position][self.idx] == self)
-    table.remove(current_notifications[scr][self.position], self.idx)
+    -- Brute force find it, the position could have been replaced.
+    seek_and_destroy(self)
 
     if (not keep_visible) or (not scr) then
         self.box.visible = false