I was basing it on what the parent commenter said. I can't really tell if he's in the wrong or you are because, as you said, I haven't looked it up myself.

Even with your version my fairness argument stands. How is it fair that a Catalan expat isn't allowed to vote, and an Andalusian that might be there just for a few months is? Expats are certainly allowed to vote in General elections.

I'm a Catalan expat and I voted already from where I am. There's a census of Spaniards living abroad. If you were there you could sign up to vote.

Ok that's better than if only currently-residing people were allowed to vote. The argument stands for Catalans living elsewhere in Spain.

But I grant that "you're allowed to vote if you can vote in the General elections as a resident of one of the four Catalan provinces" is probably as fair as one can practically get when designing this.

Catalans living elsewhere in Spain are out of luck, which seems to be due to current Estatut (if I read right) and I guess logistic challenges.