Does the spell Magic Weapon (and Greater MW) give a weapon temporary hit points? The spells by RAW simply give a enhancement bonus, and the weapon hardness and HP table states that weapons get bonuses to those stats if it has an enhancement bonus.
It isn't clear if a spell will give the bonus hardness and HP though, as its a temporary effect.
As a secondary question, does a weapon or armour with other special properties get the extra hardness and HP, even though it isn't directly a enhancement bonus? Example: a +1 flaming longsword getting bonus hardness and HP equal to a +2 weapon. If not, it continues the trend that straight-up + enhancement weapons are better than anything else, which is a bit boring when it comes to flavour.
To expand the question further, what happens when any source grants a weapon an enhancement bonus which stacks with whatever the weapon already has, like A Paladin's bonded weapon or a Magus using his Arcane Pool to grant his weapon an enhancement?
I think, per RAW, the weapon doesn't get the extra hardness/HP unless it's permanently enchanted with an additional enhancement bonus.
However, I don't see it as particularly game breaking to rule otherwise.