2 files changed, 35 insertions, 0 deletions
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index ac2973ba68..09836e747f 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -908,6 +908,12 @@ check_pum:
       }
       pum_want.active = false;
     }
+
+    if (curbuf->b_u_synced) {
+      // The K_EVENT, K_COMMAND, or K_LUA caused undo to be synced.
+      // Need to save the line for undo before inserting the next char.
+      ins_need_undo = true;
+    }
     break;
 
   case K_HOME:        // <Home>
diff --git a/src/nvim/testdir/test_undo.vim b/src/nvim/testdir/test_undo.vim
index eb47af08d7..ee8b52caaf 100644
--- a/src/nvim/testdir/test_undo.vim
+++ b/src/nvim/testdir/test_undo.vim
@@ -3,6 +3,9 @@
 " undo-able pieces.  Do that by setting 'undolevels'.
 " Also tests :earlier and :later.
 
+source check.vim
+source screendump.vim
+
 func Test_undotree()
   new
 
@@ -773,4 +776,30 @@ func Test_undo_mark()
   bwipe!
 endfunc
 
+func Test_undo_after_write()
+  " use a terminal to make undo work like when text is typed
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+      edit Xtestfile.txt
+      set undolevels=100 undofile
+      imap . <Cmd>write<CR>
+      write
+  END
+  call writefile(lines, 'Xtest_undo_after_write', 'D')
+  let buf = RunVimInTerminal('-S Xtest_undo_after_write', #{rows: 6})
+
+  call term_sendkeys(buf, "Otest.\<CR>boo!!!\<Esc>")
+  sleep 100m
+  call term_sendkeys(buf, "u")
+  call VerifyScreenDump(buf, 'Test_undo_after_write_1', {})
+
+  call term_sendkeys(buf, "u")
+  call VerifyScreenDump(buf, 'Test_undo_after_write_2', {})
+
+  call StopVimInTerminal(buf)
+  call delete('Xtestfile.txt')
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab