* We can have expressions that become true if a regex pattern in the expression
does NOT match. In this case val is NULL and we should just set the value for
the environment variable like in the pattern case.
@@ -597,7 +597,17 @@ static int match_headers(request_rec *r)
apr_table_unset(r->subprocess_env, elts[j].key);
}
else {
- if (!b->pattern) {
+ /*
+ * Do regex replacement, if we did not use a pattern, so
+ * either a regex or an expression and if we have a val
+ * or at least we did not use an expression.
+ * Background: We can have expressions that become true
+ * if a regex pattern in the expression does NOT match.
+ * In this case val is NULL and we should just set the
+ * value for the environment variable like in the pattern
+ * case.
+ */
+ if (!b->pattern && (val || !b->expr)) {
char *replaced = ap_pregsub(r->pool, elts[j].val, val,
AP_MAX_REG_MATCH, regm);
if (replaced) {
