[Tarantool-patches] [PATCH v3 3/4] replication: make anon replicas iteration safe

[Ilya Kosarev <i.kosarev@tarantool.org>]

In replicaset_follow we iterate anon replicas list: list of replicas
that haven't received an UUID. In case of successful connect replica
link is being removed from anon list. If it happens immediately,
without yield in applier, iteration breaks. Now it is fixed by
rlist_foreach_entry_safe instead of common rlist_foreach_entry.
Relevant test case is added.

Part of #4586
Closes #4576
Closes #4440
---
 src/box/replication.cc                        |  3 +-
 .../box_set_replication_stress.result         | 38 +++++++++++++++++++
 .../box_set_replication_stress.test.lua       | 17 +++++++++
 3 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 test/replication/box_set_replication_stress.result
 create mode 100644 test/replication/box_set_replication_stress.test.lua

diff --git a/src/box/replication.cc b/src/box/replication.cc
index f15e51f4d..81f19aa07 100644
--- a/src/box/replication.cc
+++ b/src/box/replication.cc
@@ -802,7 +802,8 @@ replicaset_follow(void)
 		if (replica->applier != NULL)
 			applier_resume(replica->applier);
 	}
-	rlist_foreach_entry(replica, &replicaset.anon, in_anon) {
+	struct replica *tmp;
+	rlist_foreach_entry_safe(replica, &replicaset.anon, in_anon, tmp) {
 		/* Restart appliers that failed to connect. */
 		applier_start(replica->applier);
 	}
diff --git a/test/replication/box_set_replication_stress.result b/test/replication/box_set_replication_stress.result
new file mode 100644
index 000000000..e683c0643
--- /dev/null
+++ b/test/replication/box_set_replication_stress.result
@@ -0,0 +1,38 @@
+-- test-run result file version 2
+test_run = require('test_run').new()
+ | ---
+ | ...
+SERVERS = {'master_quorum1', 'master_quorum2'}
+ | ---
+ | ...
+
+-- Deploy a cluster.
+test_run:create_cluster(SERVERS)
+ | ---
+ | ...
+test_run:wait_fullmesh(SERVERS)
+ | ---
+ | ...
+
+test_run:cmd("switch master_quorum1")
+ | ---
+ | - true
+ | ...
+repl = box.cfg.replication
+ | ---
+ | ...
+for i = 1, 1000 do              \
+    box.cfg{replication = ""}   \
+    box.cfg{replication = repl} \
+end
+ | ---
+ | ...
+test_run:cmd("switch default")
+ | ---
+ | - true
+ | ...
+
+-- Cleanup.
+test_run:drop_cluster(SERVERS)
+ | ---
+ | ...
diff --git a/test/replication/box_set_replication_stress.test.lua b/test/replication/box_set_replication_stress.test.lua
new file mode 100644
index 000000000..407e91e0f
--- /dev/null
+++ b/test/replication/box_set_replication_stress.test.lua
@@ -0,0 +1,17 @@
+test_run = require('test_run').new()
+SERVERS = {'master_quorum1', 'master_quorum2'}
+
+-- Deploy a cluster.
+test_run:create_cluster(SERVERS)
+test_run:wait_fullmesh(SERVERS)
+
+test_run:cmd("switch master_quorum1")
+repl = box.cfg.replication
+for i = 1, 1000 do              \
+    box.cfg{replication = ""}   \
+    box.cfg{replication = repl} \
+end
+test_run:cmd("switch default")
+
+-- Cleanup.
+test_run:drop_cluster(SERVERS)
-- 
2.17.1