#!/usr/bin/env tarantool

local tap = require('tap')
local net_box = require('net.box')
local urilib = require('uri')

box.cfg({
    listen = os.getenv('LISTEN') or 'localhost:3301',
})

box.schema.user.grant('guest', 'read,write,execute', 'universe')

box.schema.create_space('s')
box.space.s:create_index('pk')
box.space.s:create_index('sk', {unique = false})

local test = tap.test('gh-4091-net.box-indexes-are-always-non-unique')
test:plan(2)

local uri = urilib.parse(box.cfg.listen)
local uri = ('%s:%s'):format(uri.host or 'localhost', uri.service)
local conn = net_box.connect(uri)

test:is(conn.space.s.index.pk.unique, true, 'unique index') -- !! fails !!
test:is(conn.space.s.index.sk.unique, false, 'non-unique index')

box.space.s:drop()
box.schema.user.revoke('guest', 'read,write,execute', 'universe')

os.exit(test:check() == true and 0 or 1)

diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
index b3139a3f5..e1c4b652b 100644
--- a/src/box/lua/net_box.lua
+++ b/src/box/lua/net_box.lua
@@ -1253,7 +1253,7 @@ function remote_methods:_install_schema(schema_version, spaces, indices)
                 }
                 idx.parts[k] = pk
             end
-            idx.unique = not not index[OPTS].is_unique
+            idx.unique = not not index[OPTS].unique
         end
 
         if sl[idx.space] ~= nil then