jillybean, on 2013-December-29, 20:53, said:
(1x) 1y (P) 2y is very different from the auction I posted in the OP where the 2nd seat bidder is unlimited and partner has popped up after 2 bidding opponents.
That is true but even so, your partner showed some game interest with his 3♣ bid (presumably?) so he must have had a good hand. Good enough to force to 3♠ opposite whatever the minimum for your 1♠ bid might be

I would probably have passed and I don't think 3♠ is such a terrible contract. I would think 3♠+1 should be at least a normal result. I am not sure if I really want to be in game on this hand.
Did you consider 3NT as an alternative to 4♠? If partner has good long clubs you could easily have the first 9 tricks, otherwise partner has to have Qxx in hearts or such. And partner knows you have five spades, it is not like your suit quality makes it important to restate that! If partner has only three trumps, 3NT might be a better game. If he has four he will correct to 4♠.
As it happens, 3NT probable wouldn't make (♣T needs to fall).