api: release lock in pool:put(conn)

The absence of this operation could lead to an infinite bloсking
when used with fiber (case in tests).

Closes #34

Author: romanhabibov

mysql/init.lua

@@ -68,10 +68,11 @@ local function conn_put(conn)
     ffi.gc(conn.__gc_hook, nil)
     if not conn.queue:get() then
         conn.usable = false
-        conn.queue:put()
+        conn.queue:put(false)
         return POOL_EMPTY_SLOT
     end
     conn.usable = false
+    conn.queue:put(false)
     return mysqlconn
 end
 

test/mysql.test.lua

@@ -516,39 +516,44 @@ local function test_underlying_conn_closed_during_gc(test)
     test:ok(ffi.C.fcntl(handle, F_GETFD) == -1, 'descriptor is closed')
 end
 
-local function test_block_fiber1(conn)
-    print('fiber1')
-    conn:execute('SELECT sleep(0.01)')
-    print('fiber 1 end')
-end
-
 local fiber_2
 
 local function test_block_fiber2(conn)
-    print('fiber2')
     fiber_2 = fiber.self()
     for _ = 1, 2 do
         conn:execute('SELECT sleep(0.01)')
     end
-    print('fiber 2 end')
-end
-
-local function test_block_fiber3(pool, conn)
-    print('fiber3')
-    pool:put(conn)
-    print('fiber 3 end')
 end
 
 local function test_block_fiber_inf(test, pool)
-    test:plan(1)
+    test:plan(2)
+    -- Check that the second fiber is not blocked infinitely, when
+    -- the third fiber do pool:put(conn) or conn:close().
     local conn = pool:get()
-    fiber.create(test_block_fiber1, conn)
+     -- First.
+    fiber.create(conn.execute, conn, 'SELECT sleep(0.01)')
+     -- Second.
+    fiber.create(test_block_fiber2, conn)
+     -- Third.
+    fiber.create(pool.put, pool, conn)
+    while fiber.status(fiber_2) ~= 'dead' do
+        fiber.sleep(0)
+    end
+    test:ok(fiber.status(fiber_2) == 'dead', 'fiber is not blocked')
+
+    local conn, err = mysql.connect({ host = host, port = port, user = user,
+        password = password, db = db })
+    if conn == nil then error(err) end
+     -- First.s
+    fiber.create(conn.execute, conn, 'SELECT sleep(0.01)')
+     -- Second.
     fiber.create(test_block_fiber2, conn)
-    fiber.create(test_block_fiber3, pool, conn)
+     -- Third.
+    fiber.create(conn.close, conn)
     while fiber.status(fiber_2) ~= 'dead' do
         fiber.sleep(0)
     end
-    test:ok(true, 'fiber is not blocked')
+    test:ok(fiber.status(fiber_2) == 'dead', 'fiber is not blocked')
 end
 
 local test = tap.test('mysql connector')