From 02a0bef92b999c14083563d32a538693f681d4f2 Mon Sep 17 00:00:00 2001
From: nicm <nicm@openbsd.org>
Date: Mon, 28 Sep 2026 16:23:56 +0000
Subject: [PATCH] Copy all #s at once when multiple are seen before [ rather
 than only copying one at a time which can be very slow.

(cherry picked from commit 5fbfaca6a87da13c56709182af6b53b5d77bae6d)
---
 format.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/format.c b/format.c
index ecb9634f6..f35c9719c 100644
--- a/format.c
+++ b/format.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.419 2026/09/28 16:00:28 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.420 2026/09/28 16:23:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -6824,6 +6824,19 @@ format_expand1(struct format_expand_state *es, const char *fmt)
 				fmt = ptr + 1;
 				continue;
 			}
+			if (ch == '#') {
+				while (len - off < (n / 2) + 1) {
+					buf = xreallocarray(buf, 2, len);
+					len *= 2;
+				}
+				memset(buf + off, '#', n / 2);
+				off += (n / 2);
+				if (n % 2 != 0)
+					fmt = ptr - 1;
+				else
+					fmt = ptr;
+				continue;
+			}
 			/* FALLTHROUGH */
 		case '}':
 		case ',':