check for valid window before resizing (#306)

when calling `notify` on a notification instance quickly after the
window has been dismissed, the on_close callback was not yet called as
it is handled asynchronously by vim-notify. Yet, the window is gone and
its winID is not valid anymore. Since the on_open callback is also
handled async, the winID has not been replaced by then. Skipping the
resize should be fine as the new notification should be displayed with
the correct size to begin with

Author: Denzel

lua/cmake-tools/notification.lua

@@ -71,6 +71,7 @@ function Notification:notify(msg, level, opts)
   self.opts.title = "CMakeTools"
   self.opts.on_close = function(win)
     self.closed = true
+    self.spinner_idx = 1
     if on_close then
       on_close(win)
     end
@@ -85,15 +86,18 @@ function Notification:notify(msg, level, opts)
 
   render(self)
 
-  -- update the notification width when the message was updated
-  local timeDigits = 8
-  local headlineLength = (self.opts.icon and (#self.opts.icon + 1) or 0)
-    + #self.opts.title
-    + 3 -- padding between title and time
-    + timeDigits
-
-  if self.width then
-    vim.api.nvim_win_set_width(self.win, math.max(#self.msg + 1, headlineLength))
+  -- We have to check for a valid window here as it seems notify invokes the on_close callback async.
+  -- Hence checking for self.win ~= nil does not work as it gets deleted too late
+  if vim.api.nvim_win_is_valid(self.win) then
+    if self.width then
+      -- update the notification width when the message was updated
+      local timeDigits = 8
+      local headlineLength = (self.opts.icon and (#self.opts.icon + 1) or 0)
+        + #self.opts.title
+        + 3 -- padding between title and time
+        + timeDigits
+      vim.api.nvim_win_set_width(self.win, math.max(#self.msg + 1, headlineLength))
+    end
   end
 end