fix(repeat_cmdline): Save the repeat_cmdline when calling a userfunc.userregs_2

There's a very subtle bug when calling a userfunc where the redo buffer
is saved, but the repeat_cmdline is not. This causes the redo buffer on
do-repeat to call the most recently executed userfunc rather than the
userfunc it should be dot-repeating.

This is only an issue when trying to dot-repeat a userfunction within a
user function.

I found this bug when experimenting with using text motions,
specifically the Z* verbs in fieldmarshal. Specifically the Z* motions
(for inserting/appending before/after a text object) would be
dot-repeatable for builtin text objects, but would not be dot-repeatable
for user-defined text objects.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index 89bb1dca9b..52db600010 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -1006,6 +1006,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   bool started_profiling = false;
   bool did_save_redo = false;
   save_redo_T save_redo;
+  char* saved_repeat_cmdline = NULL;
 
   // If depth of calling is getting too high, don't execute the function
   if (depth >= p_mfd) {
@@ -1018,6 +1019,9 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   // Save search patterns and redo buffer.
   save_search_patterns();
   if (!ins_compl_active()) {
+    if (repeat_cmdline) {
+      saved_repeat_cmdline = xstrdup(repeat_cmdline);
+    }
     saveRedobuff(&save_redo);
     did_save_redo = true;
   }
@@ -1362,6 +1366,8 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   // restore search patterns and redo buffer
   if (did_save_redo) {
     restoreRedobuff(&save_redo);
+    xfree(repeat_cmdline);
+    repeat_cmdline = saved_repeat_cmdline;
   }
   restore_search_patterns();
 }