Exactly. Like it never happened in the past. hahahaha buhahaha
Don`t confuse strategic respond and attack. Forget daily politics and propaganda of all kind.
Whenever Germanics moved in Drang Nach Osten and entered Poland, Russia parried with seizing parts of Poland. Considered Poland Slavic and acted to preserve, not Polish sure, but its own interests. Still, that suited to Slavs in Poland which wanted to stay Slavic.
Now is different. Official Poland convinced Russia that Poland isn`t Slavic first. In all its territory. Slavs are there in Poland, in some number but they should fight if they wants to exist as Slavs. Those are even rules of this new architecture of Europe. You are Slavic? Fine. Fight for it. Or Germanic, Franko or whatever. Fight for it.
If you ask me, in case of Poland`s war with Germany, chances are that Serbia came in aid to Slavs in Poland who resist and then Russia could be involved. That is the only viable mechanism. Frankly. See, Adam Mizckiewish would tell you the same. When comes to connection with Poland, Serbians are irrational and Russia can`t allow our demise. If Poland I would be very careful not to lose Serbian love.