From afc7e08a20da95d6facf8357a82b7321cb64cfcf Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Tue, 17 Jul 2018 17:42:25 +0200
Subject: [PATCH] Panic when we are sending an error to our master/slave.

Related to #5135, see discussion there.
---
 src/networking.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/networking.c b/src/networking.c
index f6882f69..22850a4b 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -349,6 +349,11 @@ void addReplyErrorLength(client *c, const char *s, size_t len) {
         serverLog(LL_WARNING,"== CRITICAL == This %s is sending an error "
                              "to its %s: '%s' after processing the command "
                              "'%s'", from, to, s, cmdname);
+        /* Here we want to panic because when an instance is sending an
+         * error to another instance in the context of replication, this can
+         * only create some kind of offset or data desynchronization. Better
+         * to catch it ASAP and crash instead of continuing. */
+        serverPanic("Continuing is unsafe: replication protocol violation.");
     }
 }