Successful note_imminent_preimage is free

frame/democracy/src/lib.rs

@@ -160,7 +160,7 @@ use sp_runtime::{
 use codec::{Encode, Decode, Input};
 use frame_support::{
 	decl_module, decl_storage, decl_event, decl_error, ensure, Parameter,
-	weights::{Weight, DispatchClass},
+	weights::{Weight, DispatchClass, Pays},
 	traits::{
 		Currency, ReservableCurrency, LockableCurrency, WithdrawReason, LockIdentifier, Get,
 		OnUnbalanced, BalanceStatus, schedule::{Named as ScheduleNamed, DispatchTime}, EnsureOrigin
@@ -491,14 +491,14 @@ decl_event! {
 		Vetoed(AccountId, Hash, BlockNumber),
 		/// A proposal's preimage was noted, and the deposit taken. [proposal_hash, who, deposit]
 		PreimageNoted(Hash, AccountId, Balance),
-		/// A proposal preimage was removed and used (the deposit was returned). 
+		/// A proposal preimage was removed and used (the deposit was returned).
 		/// [proposal_hash, provider, deposit]
 		PreimageUsed(Hash, AccountId, Balance),
 		/// A proposal could not be executed because its preimage was invalid. [proposal_hash, ref_index]
 		PreimageInvalid(Hash, ReferendumIndex),
 		/// A proposal could not be executed because its preimage was missing. [proposal_hash, ref_index]
 		PreimageMissing(Hash, ReferendumIndex),
-		/// A registered preimage was removed and the deposit collected by the reaper. 
+		/// A registered preimage was removed and the deposit collected by the reaper.
 		/// [proposal_hash, provider, deposit, reaper]
 		PreimageReaped(Hash, AccountId, Balance, AccountId),
 		/// An [account] has been unlocked successfully.
@@ -1119,18 +1119,24 @@ decl_module! {
 		/// see `weight_for::note_preimage`
 		/// # </weight>
 		#[weight = weight_for::note_imminent_preimage::<T>((encoded_proposal.len() as u32).into())]
-		fn note_imminent_preimage(origin, encoded_proposal: Vec<u8>) {
+		fn note_imminent_preimage(origin, encoded_proposal: Vec<u8>) -> DispatchResultWithPostInfo {
 			Self::note_imminent_preimage_inner(ensure_signed(origin)?, encoded_proposal)?;
+			// We check that this preimage was not uploaded before in `note_imminent_preimage_inner`,
+			// thus this call can only be successful once. If successful, user does not pay a fee.
+			Ok(Pays::No.into())
 		}
 
 		/// Same as `note_imminent_preimage` but origin is `OperationalPreimageOrigin`.
 		#[weight = (
 			weight_for::note_imminent_preimage::<T>((encoded_proposal.len() as u32).into()),
 			DispatchClass::Operational,
 		)]
-		fn note_imminent_preimage_operational(origin, encoded_proposal: Vec<u8>) {
+		fn note_imminent_preimage_operational(origin, encoded_proposal: Vec<u8>) -> DispatchResultWithPostInfo {
 			let who = T::OperationalPreimageOrigin::ensure_origin(origin)?;
 			Self::note_imminent_preimage_inner(who, encoded_proposal)?;
+			// We check that this preimage was not uploaded before in `note_imminent_preimage_inner`,
+			// thus this call can only be successful once. If successful, user does not pay a fee.
+			Ok(Pays::No.into())
 		}
 
 		/// Remove an expired proposal preimage and collect the deposit.