commit 814ca94cbcba61a11485dedf80f6b35c34e4d74b
Author: Willy Tarreau <w@1wt.eu>
Date:   Fri Apr 19 11:35:22 2019 +0200

    BUG/MEDIUM: maps: only try to parse the default value when it's present
    
    Maps returning an IP address (e.g. map_str_ip) support an optional
    default value which must be parsed. Unfortunately the parsing code does
    not check for this argument's existence and uncondtionally tries to
    resolve the argument whenever the output is of type address, resulting
    in segfaults at parsing time when no such argument is provided. This
    patch adds the appropriate check.
    
    This fix may be backported as far as 1.6.
    
    (cherry picked from commit aa5801bcaade82ce58b9a70f320b7d0389e444b0)
    Signed-off-by: Willy Tarreau <w@1wt.eu>
    (cherry picked from commit 0ad6d18945467f4d6defaad619ae49f939770ba2)
    Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/src/map.c b/src/map.c
index da399088..211d1911 100644
--- a/src/map.c
+++ b/src/map.c
@@ -142,10 +142,10 @@ int sample_load_map(struct arg *arg, struct sample_conv *conv,
 	                            1, err, file, line))
 		return 0;
 
-	/* the maps of type IP have a string as defaultvalue. This
-	 * string canbe anipv4 or an ipv6, we must convert it.
+	/* the maps of type IP support a string as default value. This
+	 * string can be an ipv4 or an ipv6, we must convert it.
 	 */
-	if (desc->conv->out_type == SMP_T_ADDR) {
+	if (arg[1].type != ARGT_STOP && desc->conv->out_type == SMP_T_ADDR) {
 		struct sample_data data;
 		if (!map_parse_ip(arg[1].data.str.str, &data)) {
 			memprintf(err, "map: cannot parse default ip <%s>.", arg[1].data.str.str);