Fix bool settings parsing in config

dbms/src/Core/SettingsCommon.cpp

@@ -63,6 +63,17 @@ void SettingNumber<Type>::set(const String & x)
     set(parse<Type>(x));
 }
 
+template <>
+void SettingNumber<bool>::set(const String & x)
+{
+    if (x == "false")
+        set(false);
+    else if (x == "true")
+        set(true);
+    else
+        set(parse<bool>(x));
+}
+
 template <typename Type>
 void SettingNumber<Type>::serialize(WriteBuffer & buf) const
 {

dbms/tests/integration/test_replica_can_become_leader/configs/notleader.xml

@@ -0,0 +1,5 @@
+<yandex>
+    <merge_tree>
+        <replicated_can_become_leader>false</replicated_can_become_leader>
+    </merge_tree>
+</yandex>

dbms/tests/integration/test_replica_can_become_leader/test.py

@@ -0,0 +1,33 @@
+import pytest
+
+from helpers.cluster import ClickHouseCluster
+
+cluster = ClickHouseCluster(__file__)
+node1 = cluster.add_instance('node1', main_configs=['configs/notleader.xml'], with_zookeeper=True)
+node2 = cluster.add_instance('node2', with_zookeeper=True)
+node3 = cluster.add_instance('node3', with_zookeeper=True)
+
+@pytest.fixture(scope="module")
+def start_cluster():
+    try:
+        cluster.start()
+
+        for i, node in enumerate((node1, node2, node3)):
+            node.query(
+                '''
+                CREATE TABLE test_table(date Date, id UInt32, dummy UInt32)
+                ENGINE = ReplicatedMergeTree('/clickhouse/tables/test_table', '{}')
+                PARTITION BY date ORDER BY id
+                '''.format(i)
+            )
+
+        yield cluster
+
+    finally:
+        cluster.shutdown()
+
+
+def test_can_become_leader(start_cluster):
+    assert node1.query("select can_become_leader from system.replicas where table = 'test_table'") == '0\n'
+    assert node2.query("select can_become_leader from system.replicas where table = 'test_table'") == '1\n'
+    assert node3.query("select can_become_leader from system.replicas where table = 'test_table'") == '1\n'