3 files changed, 14 insertions, 5 deletions
diff --git a/src/lib/dispatch/.may_include b/src/lib/dispatch/.may_include
index 7f2df5859f..884f4c0dbc 100644
--- a/src/lib/dispatch/.may_include
+++ b/src/lib/dispatch/.may_include
@@ -8,3 +8,4 @@ lib/dispatch/*.h
 lib/intmath/*.h
 lib/log/*.h
 lib/malloc/*.h
+lib/testsupport/*.h
+\ No newline at end of file
diff --git a/src/lib/dispatch/dispatch_cfg.h b/src/lib/dispatch/dispatch_cfg.h
index 61fade7240..348dce8d40 100644
--- a/src/lib/dispatch/dispatch_cfg.h
+++ b/src/lib/dispatch/dispatch_cfg.h
@@ -8,6 +8,7 @@
 #define TOR_DISPATCH_CFG_H
 
 #include "lib/dispatch/msgtypes.h"
+#include "lib/testsupport/testsupport.h"
 
 /**
  * A "dispatch_cfg" is the configuration used to set up a dispatcher.
@@ -36,4 +37,9 @@ int dcfg_add_recv(dispatch_cfg_t *cfg, message_id_t msg,
 
 void dcfg_free_(dispatch_cfg_t *cfg);
 
+#ifdef DISPATCH_NEW_PRIVATE
+struct smartlist_t;
+STATIC int max_in_u16_sl(const struct smartlist_t *sl, int dflt);
+#endif
+
 #endif /* !defined(TOR_DISPATCH_CFG_H) */
diff --git a/src/lib/dispatch/dispatch_new.c b/src/lib/dispatch/dispatch_new.c
index b89ef43ea7..d8e59d610a 100644
--- a/src/lib/dispatch/dispatch_new.c
+++ b/src/lib/dispatch/dispatch_new.c
@@ -9,6 +9,7 @@
  * \brief Code to construct a dispatch_t from a dispatch_cfg_t.
  **/
 
+#define DISPATCH_NEW_PRIVATE
 #define DISPATCH_PRIVATE
 #include "orconfig.h"
 
@@ -26,14 +27,14 @@
 
 /** Given a smartlist full of (possibly NULL) pointers to uint16_t values,
  * return the largest value, or dflt if the list is empty. */
-static int
-max_in_sl(const smartlist_t *sl, int dflt)
+STATIC int
+max_in_u16_sl(const smartlist_t *sl, int dflt)
 {
   uint16_t *maxptr = NULL;
   SMARTLIST_FOREACH_BEGIN(sl, uint16_t *, u) {
     if (!maxptr)
       maxptr = u;
-    else if (*u > *maxptr)
+    else if (u && *u > *maxptr)
       maxptr = u;
   } SMARTLIST_FOREACH_END(u);
 
@@ -118,11 +119,12 @@ dispatch_new(const dispatch_cfg_t *cfg)
                             smartlist_len(cfg->recv_by_msg)) + 1;
 
   /* Any channel that any message has counts towards the number of channels. */
-  const size_t n_chans = (size_t) MAX(1, max_in_sl(cfg->chan_by_msg,0)) + 1;
+  const size_t n_chans = (size_t)
+    MAX(1, max_in_u16_sl(cfg->chan_by_msg,0)) + 1;
 
   /* Any type that a message has, or that has functions, counts towards
    * the number of types. */
-  const size_t n_types = (size_t) MAX(max_in_sl(cfg->type_by_msg,0),
+  const size_t n_types = (size_t) MAX(max_in_u16_sl(cfg->type_by_msg,0),
                                       smartlist_len(cfg->fns_by_type)) + 1;
 
   d->n_msgs = n_msgs;