From 186340c9cd02ae383bc6b39c353ad5317d4ee574 Mon Sep 17 00:00:00 2001
From: Henrik Holst <henrik.holst@millistream.com>
Date: Thu, 10 Feb 2022 18:47:08 +0100
Subject: [PATCH] mprintf: remove strlen calls on empty strings in
 dprintf_formatf

Turns out that in dprintf_formatf we did a strlen on empty strings, a
bit strange is how common this actually is, 24 alone when doing a simple
GET from https://curl.se

Closes #8427
---
 lib/mprintf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/mprintf.c b/lib/mprintf.c
index b109379bf2..13812010b3 100644
--- a/lib/mprintf.c
+++ b/lib/mprintf.c
@@ -829,6 +829,8 @@ static int dprintf_formatf(
         }
         else if(prec != -1)
           len = (size_t)prec;
+        else if(*str == '\0')
+          len = 0;
         else
           len = strlen(str);