3 files changed, 23 insertions, 5 deletions
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index c5fa0f12cc..b56034b92d 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -95,7 +95,6 @@ PRAGMA_DIAG_POP
 
 
 static char *e_listarg = N_("E686: Argument of %s must be a List");
-static char *e_stringreq = N_("E928: String required");
 static char *e_invalwindow = N_("E957: Invalid window number");
 
 /// Dummy va_list for passing to vim_snprintf
@@ -1877,10 +1876,12 @@ static void f_eventhandler(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_executable(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  const char *name = tv_get_string(&argvars[0]);
+  if (tv_check_for_string(&argvars[0]) == FAIL) {
+    return;
+  }
 
   // Check in $PATH and also check directly if there is a directory name
-  rettv->vval.v_number = os_can_exe(name, NULL, true);
+  rettv->vval.v_number = os_can_exe(tv_get_string(&argvars[0]), NULL, true);
 }
 
 typedef struct {
@@ -1984,10 +1985,13 @@ static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 /// "exepath()" function
 static void f_exepath(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  const char *arg = tv_get_string(&argvars[0]);
+  if (tv_check_for_string(&argvars[0]) == FAIL) {
+    return;
+  }
+
   char *path = NULL;
 
-  (void)os_can_exe(arg, &path, true);
+  (void)os_can_exe(tv_get_string(&argvars[0]), &path, true);
 
   rettv->v_type = VAR_STRING;
   rettv->vval.v_string = (char_u *)path;
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index b62820fecc..02d32a4f86 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -2953,6 +2953,19 @@ float_T tv_get_float(const typval_T *const tv)
   return 0;
 }
 
+// Give an error and return FAIL unless "tv" is a non-empty string.
+int tv_check_for_string(const typval_T *const tv)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
+{
+  if (tv->v_type != VAR_STRING
+      || tv->vval.v_string == NULL
+      || *tv->vval.v_string == NUL) {
+    EMSG(_(e_stringreq));
+    return FAIL;
+  }
+  return OK;
+}
+
 /// Get the string value of a "stringish" VimL object.
 ///
 /// @param[in]  tv  Object to get value of.
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index e0853e900f..c53c1546a4 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -935,6 +935,7 @@ EXTERN char_u e_readonly[] INIT(= N_(
     "E45: 'readonly' option is set (add ! to override)"));
 EXTERN char_u e_readonlyvar[] INIT(= N_(
     "E46: Cannot change read-only variable \"%.*s\""));
+EXTERN char_u e_stringreq[] INIT(= N_("E928: String required"));
 EXTERN char_u e_dictreq[] INIT(= N_("E715: Dictionary required"));
 EXTERN char_u e_toomanyarg[] INIT(= N_(
     "E118: Too many arguments for function: %s"));