On Tue, Aug 28, 2018 at 07:22:26PM +0300, Olga Arkhangelskaia wrote:
> When we try to connect one master more than once we used to have
> assertion instead of error.
>
> Closes #3610
> ---
> https://github.com/tarantool/tarantool/issues/3610
> https://github.com/tarantool/tarantool/tree/OKriw/assert_fail_when_connect_master_twice

Broken link.

>
>  src/box/box.cc            | 14 ++++++++++++++
>  test/box-tap/cfg.test.lua |  8 +++++++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/src/box/box.cc b/src/box/box.cc
> index 8d7454d1f..3a571ae3c 100644
> --- a/src/box/box.cc
> +++ b/src/box/box.cc
> @@ -369,9 +369,23 @@ static void
>  box_check_replication(void)
>  {
>       int count = cfg_getarr_size("replication");
> +     char *repl[count-1];
>       for (int i = 0; i < count; i++) {
>               const char *source = cfg_getarr_elem("replication", i);
>               box_check_uri(source, "replication");
> +             repl[i] = strdup(source);
> +             if (repl[i] == NULL) {
> +                     tnt_raise(OutOfMemory, sizeof(*source), "source", "malloc");
> +             }
> +             for (int j = i; j >= 1; j--) {
> +                     if (strcmp(repl[i], repl[j-1]) == 0) {
> +                             tnt_raise(ClientError, ER_CFG, "replication",
> +                                       "duplication of replication source");
> +                     }
> +             }
> +     }
> +     for (int i = 0; i < count; i++) {
> +             free(repl[i]);

This is totally wrong, because different URLs can point to the same
instance, e.g.

Instance 1: box.cfg{listen = 12345}

Instance 2: box.cfg{replication = {12345, 'localhost:12345'}}

Crash.

All you're supposed to do is fix the checks in replication.cc

>       }
>  }
> 
> diff --git a/test/box-tap/cfg.test.lua b/test/box-tap/cfg.test.lua
> index 5e72004ca..b227c5edb 100755
> --- a/test/box-tap/cfg.test.lua
> +++ b/test/box-tap/cfg.test.lua
> @@ -6,7 +6,7 @@ local socket = require('socket')
>  local fio = require('fio')
>  local uuid = require('uuid')
>  local msgpack = require('msgpack')
> -test:plan(90)
> +test:plan(91)
> 
>  --------------------------------------------------------------------------------
>  -- Invalid values
> @@ -446,5 +446,11 @@ code = string.format(code_fmt, dir, instance_uuid, uuid.new())
>  test:is(run_script(code), PANIC, "replicaset_uuid mismatch")
>  fio.rmdir(dir)
> 
> +--
> +--gh-3610: assertion failure when trying to connect to the same master more than once
> +--
> +status, reason = pcall(box.cfg, {listen = 3303, replication={3303,3303}})
> +test:ok(not status and reason:match("Incorrect"), "Duplication of replication source")
> +

The test passes with and without your patch, i.e. useless.

Besides, it doesn't test all cases described in the issue.