fix: cancel update if view becomes out of focus (#472)

Co-authored-by: Sindre T. Strøm <sindrets@gmail.com>

Author: 8veStory

lua/diffview/scene/views/diff/diff_view.lua

@@ -327,6 +327,12 @@ DiffView.update_files = debounce.debounce_trailing(
   async.wrap(function(self, callback)
     await(async.scheduler())
 
+    -- Never update unless the view is in focus
+    if self.tabpage ~= api.nvim_get_current_tabpage() then
+      callback({ "The update was cancelled." })
+      return
+    end
+
     ---@type PerfTimer
     local perf = PerfTimer("[DiffView] Status Update")
     self:ensure_layout()
@@ -344,19 +350,24 @@ DiffView.update_files = debounce.debounce_trailing(
     end
 
     local index_stat = pl:stat(pl:join(self.adapter.ctx.dir, "index"))
-    local last_winid = api.nvim_get_current_win()
 
     ---@type string[]?, FileDict
     local err, new_files = await(self:get_updated_files())
+    await(async.scheduler())
 
     if err then
       utils.err("Failed to update files in a diff view!", true)
       logger:error("[DiffView] Failed to update files!")
-      await(async.scheduler())
       callback(err)
       return
     end
 
+    -- Stop the update if the view is no longer in focus.
+    if self.tabpage ~= api.nvim_get_current_tabpage() then
+      callback({ "The update was cancelled." })
+      return
+    end
+
     perf:lap("received new file list")
 
     local files = {
@@ -365,8 +376,6 @@ DiffView.update_files = debounce.debounce_trailing(
       { cur_files = self.files.staged, new_files = new_files.staged },
     }
 
-    await(async.scheduler())
-
     for _, v in ipairs(files) do
       -- We diff the old file list against the new file list in order to find
       -- the most efficient way to morph the current list into the new. This
@@ -473,10 +482,6 @@ DiffView.update_files = debounce.debounce_trailing(
     end
     self:set_file(self.panel.cur_file or self.panel:next_file(), false, not self.initialized)
 
-    if api.nvim_win_is_valid(last_winid) then
-      api.nvim_set_current_win(last_winid)
-    end
-
     self.update_needed = false
     perf:time()
     logger:lvl(5):debug(perf)