...or the attack is seen as blatant aggression and the world sides with Germany, with the USSR and Lithuania jumping in to carve Poland like a turkey.The Polish leader reads "Mein Kampf" and the part with the "Lebensraum". As soon as Hitler rearms, he forms alliances with other countries. When the first fairly able country joins in (Czechoslovaki or France) and supplies are guaranteed (GB, Scandinavia, France, or US), he attacks, using quotes from Hitler's book as justification.
If Silesia is taken fast enough and enough damage is done to most other main production centers, Germany might even be forced into a humiliating peace.
...or the attack is seen as blatant aggression and the world sides with Germany, with the USSR and Lithuania jumping in to carve Poland like a turkey.
Not to mention the fact that Britain would freak out, OTL occupation of the Ruhr was seriously worrying them as it was about the possible resurgence of a Napoleonic-style French hegemony, they would take this as confirmation and switch to alliance with Germany.
Not too mention Poland was already seen as enfant terrible for having managed it to run petty conflicts with all its neighbours. If Poland acts up again, it might not get all that much help.