fix(coverity): error handling CHECKED_RETURN #31618

CID 516406:  Error handling issues  (CHECKED_RETURN)
    /src/nvim/api/vimscript.c: 284 in nvim_call_dict_function()
    278       Object rv = OBJECT_INIT;
    279
    280       typval_T rettv;
    281       bool mustfree = false;
    282       switch (dict.type) {
    283       case kObjectTypeString:
    >>>     CID 516406:  Error handling issues  (CHECKED_RETURN)
    >>>     Calling "eval0" without checking return value (as is done elsewhere 10 out of 12 times).
    284         TRY_WRAP(err, {
    285           eval0(dict.data.string.data, &rettv, NULL, &EVALARG_EVALUATE);
    286           clear_evalarg(&EVALARG_EVALUATE, NULL);
    287         });
    288         if (ERROR_SET(err)) {
    289           return rv;

1 files changed, 12 insertions, 8 deletions

diff --git a/src/nvim/api/vimscript.c b/src/nvim/api/vimscript.c
index 67db615b20..e2aac07258 100644
--- a/src/nvim/api/vimscript.c
+++ b/src/nvim/api/vimscript.c
@@ -229,10 +229,9 @@ static Object _call_function(String fn, Array args, dict_T *self, Arena *arena,
   funcexe.fe_selfdict = self;
 
   TRY_WRAP(err, {
-    // call_func() retval is deceptive, ignore it.  Instead we set `msg_list`
-    // (see above) to capture abort-causing non-exception errors.
-    call_func(fn.data, (int)fn.size, &rettv, (int)args.size,
-              vim_args, &funcexe);
+    // call_func() retval is deceptive, ignore it.  Instead TRY_WRAP sets `msg_list` to capture
+    // abort-causing non-exception errors.
+    (void)call_func(fn.data, (int)fn.size, &rettv, (int)args.size, vim_args, &funcexe);
   });
 
   if (!ERROR_SET(err)) {
@@ -280,18 +279,23 @@ Object nvim_call_dict_function(Object dict, String fn, Array args, Arena *arena,
   typval_T rettv;
   bool mustfree = false;
   switch (dict.type) {
-  case kObjectTypeString:
+  case kObjectTypeString: {
+    int eval_ret;
     TRY_WRAP(err, {
-      eval0(dict.data.string.data, &rettv, NULL, &EVALARG_EVALUATE);
-      clear_evalarg(&EVALARG_EVALUATE, NULL);
-    });
+        eval_ret = eval0(dict.data.string.data, &rettv, NULL, &EVALARG_EVALUATE);
+        clear_evalarg(&EVALARG_EVALUATE, NULL);
+      });
     if (ERROR_SET(err)) {
       return rv;
     }
+    if (eval_ret != OK) {
+      abort();  // Should not happen.
+    }
     // Evaluation of the string arg created a new dict or increased the
     // refcount of a dict. Not necessary for a RPC dict.
     mustfree = true;
     break;
+  }
   case kObjectTypeDict:
     object_to_vim(dict, &rettv, err);
     break;