From 97ac45c2f22026430a3f464dbdec5ad091c39896 Mon Sep 17 00:00:00 2001
From: Shawn Tabrizi <shawntabrizi@gmail.com>
Date: Wed, 5 Aug 2020 16:22:21 +0200
Subject: [PATCH] Successful `note_imminent_preimage` is free (#6793)
* Successful `note_imminent_preimage` is free
* update docs
* Add test for duplicate preimage
---
substrate/frame/democracy/src/lib.rs | 20 ++++++++----
.../frame/democracy/src/tests/preimage.rs | 31 +++++++++++++++++++
2 files changed, 45 insertions(+), 6 deletions(-)
diff --git a/substrate/frame/democracy/src/lib.rs b/substrate/frame/democracy/src/lib.rs
index f3a5960eb2f..e298b1e4508 100644
--- a/substrate/frame/democracy/src/lib.rs
+++ b/substrate/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
@@ -458,14 +458,14 @@ 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.
@@ -1000,7 +1000,9 @@ decl_module! {
}
/// Register the preimage for an upcoming proposal. This requires the proposal to be
- /// in the dispatch queue. No deposit is needed.
+ /// in the dispatch queue. No deposit is needed. When this call is successful, i.e.
+ /// the preimage has not been uploaded before and matches some imminent proposal,
+ /// no fee is paid.
///
/// The dispatch origin of this call must be _Signed_.
///
@@ -1014,8 +1016,11 @@ decl_module! {
/// - Db writes: `Preimages`
/// # </weight>
#[weight = T::WeightInfo::note_imminent_preimage(encoded_proposal.len() as u32)]
- 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`.
@@ -1023,9 +1028,12 @@ decl_module! {
T::WeightInfo::note_imminent_preimage(encoded_proposal.len() as u32),
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.
diff --git a/substrate/frame/democracy/src/tests/preimage.rs b/substrate/frame/democracy/src/tests/preimage.rs
index 4100a6a6b63..8a2cbaf5340 100644
--- a/substrate/frame/democracy/src/tests/preimage.rs
+++ b/substrate/frame/democracy/src/tests/preimage.rs
@@ -164,3 +164,34 @@ fn reaping_imminent_preimage_should_fail() {
assert_noop!(Democracy::reap_preimage(Origin::signed(6), h, u32::max_value()), Error::<Test>::Imminent);
});
}
+
+#[test]
+fn note_imminent_preimage_can_only_be_successful_once() {
+ new_test_ext().execute_with(|| {
+ PREIMAGE_BYTE_DEPOSIT.with(|v| *v.borrow_mut() = 1);
+
+ let r = Democracy::inject_referendum(
+ 2,
+ set_balance_proposal_hash(2),
+ VoteThreshold::SuperMajorityApprove,
+ 1
+ );
+ assert_ok!(Democracy::vote(Origin::signed(1), r, aye(1)));
+ next_block();
+
+ // First time works
+ assert_ok!(Democracy::note_imminent_preimage(Origin::signed(6), set_balance_proposal(2)));
+
+ // Second time fails
+ assert_noop!(
+ Democracy::note_imminent_preimage(Origin::signed(6), set_balance_proposal(2)),
+ Error::<Test>::DuplicatePreimage
+ );
+
+ // Fails from any user
+ assert_noop!(
+ Democracy::note_imminent_preimage(Origin::signed(5), set_balance_proposal(2)),
+ Error::<Test>::DuplicatePreimage
+ );
+ });
+}
--
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