fix(undotree): sync scroll pos with undo #36117

Problem: when undo in buffer, undotree window is not updated to
position of correct node

Solution: schedule nvim_win_set_cursor

runtime/pack/dist/opt/nvim.undotree/lua/undotree.lua

@@ -264,9 +264,11 @@ local function draw(inbuf, outbuf)
   local curseq_line = buf_apply_graph_lines(tree, graph_lines, outbuf, meta, curseq)
   vim.bo[outbuf].modifiable = false
 
-  if vim.api.nvim_win_is_valid(vim.b[outbuf].nvim_is_undotree) then
+  vim.schedule(function()
-    vim.api.nvim_win_set_cursor(vim.b[outbuf].nvim_is_undotree, { curseq_line, 0 })
+    if vim.api.nvim_win_is_valid(vim.b[outbuf].nvim_is_undotree) then
-  end
+      vim.api.nvim_win_set_cursor(vim.b[outbuf].nvim_is_undotree, { curseq_line, 0 })
+    end
+  end)
 
   return meta
 end

test/functional/plugin/undotree_spec.lua

@@ -6,6 +6,7 @@ local eq = t.eq
 local exec = n.exec
 local api = n.api
 local dedent = t.dedent
+local Screen = require('test.functional.ui.screen')
 
 ---@param reverse_tree {[integer]:integer}
 local function generate_undo_tree_from_rev(reverse_tree)
@@ -80,6 +81,28 @@ describe(':Undotree', function()
     eq('foo', api.nvim_get_current_line())
   end)
 
+  it('sync scroll pos when undo', function()
+    local screen = Screen.new(30, 10)
+    for _ = 1, n.api.nvim_get_option_value('lines', {}) do
+      api.nvim_set_current_line('foo')
+    end
+    exec 'Undotree'
+    exec 'wincmd w'
+    exec 'silent undo'
+    screen:expect([[
+      *    3   │^foo                 |
+      *    4   │{1:~                   }|
+      *    5   │{1:~                   }|
+      *    6   │{1:~                   }|
+      *    7   │{1:~                   }|
+      *    8   │{1:~                   }|
+      {21:*    9   }│{1:~                   }|
+      *    10  │{1:~                   }|
+      {2:<or  [-]  }{3:[No Name] [+]       }|
+                                    |
+    ]])
+  end)
+
   describe('branch+remove is correctly graphed', function()
     it('when branching left', function()
       generate_undo_tree_from_rev({ 0, 1, 2, 3, 1, 3, 4, 3, 2, 0 })