replicaset: soften name validation

test/replicaset-luatest/replicaset_3_test.lua

@@ -269,14 +269,24 @@ test_group.test_named_replicaset = function(g)
     t.assert_equals(rs.id, rs.name)
     t.assert_equals(replica_1_a.id, replica_1_a.name)
 
-    -- Name is not set, name mismatch error.
+    -- Name is not set, uuid is not set, name mismatch error.
     local ret, err = rs:callrw('get_uuid', {}, {timeout = 5})
     t.assert_equals(err.name, 'INSTANCE_NAME_MISMATCH')
     t.assert_equals(ret, nil)
 
+    local uuid_a = g.replica_1_a:instance_uuid()
+    -- Test, that NAME_MISMATCH error is skipped, when uuid is specified.
+    -- Before the name configuration, as a name cannot be dropped. New
+    -- replicaset in order not to rebuild it for the name configuration.
+    new_global_cfg.sharding['replicaset'].replicas['replica_1_a'].uuid =
+        g.replica_1_a:instance_uuid()
+    local rs_2 = vreplicaset.buildall(new_global_cfg).replicaset
+    ret, err = rs_2:callrw('get_uuid', {}, timeout_opts)
+    t.assert_equals(err, nil)
+    t.assert_equals(ret, uuid_a)
+
     -- Set name, everything works from now on.
     g.replica_1_a:exec(function() box.cfg{instance_name = 'replica_1_a'} end)
-    local uuid_a = g.replica_1_a:instance_uuid()
     ret, err = rs:callrw('get_uuid', {}, timeout_opts)
     t.assert_equals(err, nil)
     t.assert_equals(ret, uuid_a)

vshard/replicaset.lua

@@ -137,6 +137,7 @@ end
 --
 local function conn_vconnect_check(conn)
     local vconn = conn.vconnect
+    local replica = conn.replica
     -- conn.vconnect may be nil, if connection was created on old version
     -- and the storage was reloaded to a new one. It's also nil, when
     -- all checks were already done.
@@ -146,17 +147,20 @@ local function conn_vconnect_check(conn)
     -- Nothing to do, but wait in such case.
     if not vconn.future or not vconn.future:is_ready() then
         return nil, lerror.vshard(lerror.code.VHANDSHAKE_NOT_COMPLETE,
-                                  conn.replica.id)
+                                  replica.id)
     end
     -- Critical errors. Connection should be closed after these ones.
     local result, err = vconn.future:result()
     if not result then
         -- Failed to get response. E.g. access error.
         return nil, lerror.make(err)
     end
-    if vconn.is_named and result[1].name ~= conn.replica.name then
+    -- If name is nil, it means, name was not set yet. If uuid is specified,
+    -- then we allow mismatch between config name and nil.
+    local is_name_set = result[1].name ~= nil or replica.uuid == nil
+    if vconn.is_named and is_name_set and result[1].name ~= replica.name then
         return nil, lerror.vshard(lerror.code.INSTANCE_NAME_MISMATCH,
-                                  conn.replica.name, result[1].name)
+                                  replica.name, result[1].name)
     end
     -- Don't validate until reconnect happens.
     conn.vconnect = nil