vim-patch:8.2.5035: when splitting a window the changelist position moves

Problem:    When splitting a window the changelist position moves.
Solution:   Set the changelist index a bit later. (closes vim/vim#10493)
e6f13b473c

Cherry-pick Test_nv_hat_count() change from patch 8.2.1593.

src/nvim/testdir/test_changelist.vim

@@ -1,5 +1,40 @@
 " Tests for the changelist functionality
 
+" When splitting a window the changelist position is wrong.
+" Test the changelist position after splitting a window.
+" Test for the bug fixed by 7.4.386
+func Test_changelist()
+  let save_ul = &ul
+  enew!
+  call append('$', ['1', '2'])
+  exe "normal i\<C-G>u"
+  exe "normal Gkylpa\<C-G>u"
+  set ul=100
+  exe "normal Gylpa\<C-G>u"
+  set ul=100
+  normal gg
+  vsplit
+  normal g;
+  call assert_equal([3, 2], [line('.'), col('.')])
+  normal g;
+  call assert_equal([2, 2], [line('.'), col('.')])
+  call assert_fails('normal g;', 'E662:')
+  new
+  call assert_fails('normal g;', 'E664:')
+  %bwipe!
+  let &ul = save_ul
+endfunc
+
+" Moving a split should not change its changelist index.
+func Test_changelist_index_move_split()
+  exe "norm! iabc\<C-G>u\ndef\<C-G>u\nghi"
+  vsplit
+  normal 99g;
+  call assert_equal(0, getchangelist('%')[1])
+  wincmd L
+  call assert_equal(0, getchangelist('%')[1])
+endfunc
+
 " Tests for the getchangelist() function
 func Test_changelist_index()
   edit Xfile1.txt

src/nvim/testdir/test_normal.vim

@@ -2849,35 +2849,10 @@ func Test_gr_command()
   enew!
 endfunc
 
-" When splitting a window the changelist position is wrong.
-" Test the changelist position after splitting a window.
-" Test for the bug fixed by 7.4.386
-func Test_changelist()
-  let save_ul = &ul
-  enew!
-  call append('$', ['1', '2'])
-  exe "normal i\<C-G>u"
-  exe "normal Gkylpa\<C-G>u"
-  set ul=100
-  exe "normal Gylpa\<C-G>u"
-  set ul=100
-  normal gg
-  vsplit
-  normal g;
-  call assert_equal([3, 2], [line('.'), col('.')])
-  normal g;
-  call assert_equal([2, 2], [line('.'), col('.')])
-  call assert_fails('normal g;', 'E662:')
-  new
-  call assert_fails('normal g;', 'E664:')
-  %bwipe!
-  let &ul = save_ul
-endfunc
-
 func Test_nv_hat_count()
   %bwipeout!
   let l:nr = bufnr('%') + 1
-  call assert_fails(':execute "normal! ' . l:nr . '\<C-^>"', 'E92')
+  call assert_fails(':execute "normal! ' . l:nr . '\<C-^>"', 'E92:')
 
   edit Xfoo
   let l:foo_nr = bufnr('Xfoo')

src/nvim/window.c

@@ -1501,9 +1501,6 @@ int win_split_ins(int size, int flags, win_T *new_wp, int dir)
     }
   }
 
-  // Keep same changelist position in new window.
-  wp->w_changelistidx = oldwin->w_changelistidx;
-
   // make the new window the current window
   win_enter_ext(wp, WEE_TRIGGER_NEW_AUTOCMDS | WEE_TRIGGER_ENTER_AUTOCMDS
                 | WEE_TRIGGER_LEAVE_AUTOCMDS);
@@ -1574,6 +1571,10 @@ static void win_init(win_T *newp, win_T *oldp, int flags)
   }
   newp->w_tagstackidx = oldp->w_tagstackidx;
   newp->w_tagstacklen = oldp->w_tagstacklen;
+
+  // Keep same changelist position in new window.
+  newp->w_changelistidx = oldp->w_changelistidx;
+
   copyFoldingState(oldp, newp);
 
   win_init_some(newp, oldp);