patch 8.1.0973: pattern with syntax error gives threee error messagesv8.1.0973

Problem:    Pattern with syntax error gives threee error messages. (Kuang-che
            Wu)
Solution:   Remove outdated internal error.  Don't fall back to other engine
            after an error.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/regexp.c b/src/regexp.c
index e37c06507..5c06ada1b 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -7969,6 +7969,7 @@ vim_regcomp(char_u *expr_arg, int re_flags)
 {
     regprog_T   *prog = NULL;
     char_u	*expr = expr_arg;
+    int		save_called_emsg;
 
     regexp_engine = p_re;
 
@@ -8004,6 +8005,8 @@ vim_regcomp(char_u *expr_arg, int re_flags)
     /*
      * First try the NFA engine, unless backtracking was requested.
      */
+    save_called_emsg = called_emsg;
+    called_emsg = FALSE;
     if (regexp_engine != BACKTRACKING_ENGINE)
 	prog = nfa_regengine.regcomp(expr,
 		re_flags + (regexp_engine == AUTOMATIC_ENGINE ? RE_AUTO : 0));
@@ -8032,13 +8035,15 @@ vim_regcomp(char_u *expr_arg, int re_flags)
 	 * If the NFA engine failed, try the backtracking engine.
 	 * The NFA engine also fails for patterns that it can't handle well
 	 * but are still valid patterns, thus a retry should work.
+	 * But don't try if an error message was given.
 	 */
-	if (regexp_engine == AUTOMATIC_ENGINE)
+	if (regexp_engine == AUTOMATIC_ENGINE && !called_emsg)
 	{
 	    regexp_engine = BACKTRACKING_ENGINE;
 	    prog = bt_regengine.regcomp(expr, re_flags);
 	}
     }
+    called_emsg |= save_called_emsg;
 
     if (prog != NULL)
     {