What if Poland built its own Maginot Lines?

What if, during the interwar period, Poland developed its own version of the Maginot Line? It would have to build one in the east (presumably first due to the USSR being a greater threat before the rise of the Nazis later), and another in the west.

Potentially another could be built along the southern border with Czechoslovakia and Romania.

Would the joint German/Soviet invasion have still happened and, if so, would it be successful?