refactor: simplify opening file in new tab

fixes #1271. Also fixes opening a file in new tab when close_on_open was
true.

This introduces breaking change since we don't do any extra behavior
and let the buffer be opened by the tree.
The previous behavior was a bit old and i believe this should've been
fixed by now.
Reference this commit if unexpected behavior appears while opening files
in new tabs from nvim-tree.

Author: kyazdani42

lua/nvim-tree/actions/open-file.lua

@@ -131,33 +131,7 @@ end
 local function open_file_in_tab(filename)
   if M.quit_on_open then
     view.close()
-  else
-    -- Switch window first to ensure new window doesn't inherit settings from
-    -- NvimTree
-    if lib.target_winid > 0 and api.nvim_win_is_valid(lib.target_winid) then
-      api.nvim_set_current_win(lib.target_winid)
-    else
-      vim.cmd "wincmd p"
-    end
-  end
-
-  -- This sequence of commands are here to ensure a number of things: the new
-  -- buffer must be opened in the current tabpage first so that focus can be
-  -- brought back to the tree if it wasn't quit_on_open. It also ensures that
-  -- when we open the new tabpage with the file, its window doesn't inherit
-  -- settings from NvimTree, as it was already loaded.
-
-  vim.cmd("edit " .. vim.fn.fnameescape(filename))
-
-  local alt_bufid = vim.fn.bufnr "#"
-  if alt_bufid ~= -1 then
-    api.nvim_set_current_buf(alt_bufid)
   end
-
-  if not M.quit_on_open then
-    vim.cmd "wincmd p"
-  end
-
   vim.cmd("tabe " .. vim.fn.fnameescape(filename))
 end
 

lua/nvim-tree/view.lua

@@ -254,7 +254,7 @@ end
 function M.is_visible(opts)
   if opts and opts.any_tabpage then
     for _, v in pairs(M.View.tabpages) do
-      if a.nvim_win_is_valid(v.winnr) then
+      if v.winnr and a.nvim_win_is_valid(v.winnr) then
         return true
       end
     end