I suggest you read the combat rules, because attacks don't do damage.
To start with, specific beats general, in the Truestrike spell the "attack" can cause Radiant damage and that overrides anything that would contradict in in the general section about attacks.
However the section on attacks does not contradict it, it acctually affirms it. You should the very combat rules you are referencing:
This from the section on Making an Attack:
"Some attacks cause special effects in addition to or instead of damage."
So yes "attacks" can cause damage according to the very rules you told me to read AND according to the Truestrike spell itself.
Hits do. If the attack hits, you can do radiant damage.
In Truestrike attacks cause damage. It is right there in the spell and the damage it causes defies the laws of physics.
The attack can miss, so it cannot be the attack that does the damage, or it couldn't miss.
The attack itself causes damage as per the Truestrike description. I think that means the attack causes damage when a hit occurs, but it is still the attack is causing it, as per the description.
Now if you want I suppose you could interpret that to mean the attack causes damage regardless a hit or on a miss. I don't think that is correct and I don't I think that is reasoable, but it is not specifically refuted.
What is not up to interpretation though is that the attack itself can cause the Radiant damage because it says that specifically in the spell. So the attack itself can defy the laws of physics, therefore by your logic it is part of the spell.
LOL No. You can change it to radiant. It's a mundane weapon, so the default isn't radiant.
The "attack" can do Radiant damage.
And let's be clear you don't "change" anything. It does not say you can change the damage to Radiant it says you can
choose for the damage of the attack (not of the hit or of the weapon) to be Radiant or the weapon's type. You don't replace or change anything.
"If the attack deals damage, it can be Radiant damage or the weapon’s normal damage type (your choice)."
This claim of yours that attack=damage, means that damage=attack, which is absurd on its face.
That is not my claim. I never said attack=damage, I said the attack can cause Radiant damage because that is what the rules say. Also the section on Combat you referenced also says attacks can cause damage.
Attack does not equal damage, but attacks clearly can cause damage.
You can jump up and down and claim attacks can't cause damage, but both the general rules on combat and the specific rules on Truestrike say they can.
Next time I play, I'm going to tell the DM I just stare at the enemy and don't swing my sword, then roll an attack to do damage and see how far that gets me.
That would nto fly in my game but your game, your DM, do whatever you want.
None of this changes that fact that the rules say attacks can cause daamge and the truestrike spell says that attack can cause Radiant damage.