Design of the approval voting module for council election.

substrate/demo/runtime/src/runtime/council.rs

@@ -0,0 +1,272 @@
+// Copyright 2017 Parity Technologies (UK) Ltd.
+// This file is part of Substrate Demo.
+
+// Substrate Demo is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate Demo is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate Demo.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Council system: Handles the voting in and maintenance of council members.
+
+use rstd::prelude::*;
+use codec::KeyedVec;
+use runtime_support::storage;
+use demo_primitives::{Proposal, AccountId, Hash, BlockNumber};
+use runtime::{staking, system, session};
+use runtime::staking::Balance;
+
+// no polynomial attack:
+// all public operations should be constant time.
+// all protected operations may be at most O(public operations)
+
+// public operations:
+// - express approval (ideally, express all approvals)
+// - re-express approval (ideally, re-express all approvals)
+// - clear all approvals
+// - submit candidacy
+// protected operations:
+// - remove candidacy (remove all votes for a candidate)
+
+// for an approval vote of C councilers:
+
+// top K candidates are maintained between votes. all others are discarded.
+// - candidate removed & bond returned when elected.
+// - candidate removed & bond burned when discarded.
+
+// at the point that the vote ends, all voters' balances are snapshotted.
+
+// for B blocks following, there's a counting period whereby each of the candidates that believe
+// they fall in the top K+C voted can present themselves. they get the total stake
+// recorded (based on the snapshot); an ordered list is maintained. Noone may present themselves
+// that, if elected, would result in being included twice on the council (important since existing
+// councilers will will have their approval votes as it may be that they don't get removed), nor
+// if existing presenters would mean they're not in the top K+C.
+
+// following B blocks, the top C+K that presented themselves have their bond returned and the
+// top C candidates are elected. the top C candidates have their bond returned.
+
+// the top C candidates and all other candidates beyond the top C+K are cleared and the clearing
+// mask is appended to mask list (ready to be applied to vote arrays).
+
+// vote-clearing happens lazily, with previous write also storing the round and all subsequent
+// rounds' operations applied at the next read/write time.
+
+// vote buffer size increases as required.
+// bond taken for initial approval, returned when clearing.
+
+// vec<candidate> (list of addresses, each bonded, can contain "holes" of null addresses). Order important.
+// vec<voter> (all voters. order unimportant - just need to be enumerable.)
+// voter -> (last round, Vec<bool>)
+
+const CURRENT_VOTE: &[u8] = b"cou:cur";
+const APPROVALS_OF: &[u8] = b"cou:apr:";
+const VOTERS: &[u8] = b"cou:vrs";
+const CANDIDATES: &[u8] = b"cou:can";
+
+const CANDIDACY_BOND: &[u8] = b"cou:cbo";
+const VOTING_BOND: &[u8] = b"cou:vbo";
+
+const CARRY_COUNT: &[u8] = b"cou:cco";
+const PRESENTATION_DURATION: &[u8] = b"cou:pdu";
+
+const WINNERS: &[u8] = b"cou:win";
+
+/// How much should be locked up in order to submit one's candidacy.
+pub fn candidacy_bond() -> Balance {
+	unimplemented!();
+}
+
+/// How much should be locked up in order to be able to submit votes.
+pub fn voting_bond() -> Balance {
+	unimplemented!();
+}
+
+/// How long to give each top candidate to present themselves after the vote ends.
+pub fn presentation_duration() -> BlockNumber {
+	unimplemented!();
+}
+
+/// How many runners-up should have their approvals persist until the next vote.
+pub fn carry_count() -> u32 {
+	unimplemented!();
+}
+
+/// The current council. When there's a vote going on, this should still be used for executive
+/// matters.
+pub fn active_council() -> Vec<AccountId> {
+	unimplemented!();
+}
+
+/// The information on the current vote:
+/// - The block number where voting will end;
+/// - The specific council members to be replaced.
+pub fn current_vote() -> Option<(BlockNumber, Vec<AccountId>)> {
+	unimplemented!();
+}
+
+/// The total number of votes that have happened or are in progress.
+pub fn vote_index() -> VoteIndex {
+	unimplemented!();
+}
+
+/// The queue of candidate indices that will be cleared.
+pub fn candidate_clear_queue() -> {
+	unimplemented!();
+}
+
+/// The last cleared vote index that this voter was last active at.
+pub fn voter_last_active(voter: &AddressId) -> VoteIndex {
+	unimplemented!();
+}
+
+pub mod public {
+	use super::*;
+
+	/// Remove a voter. For it not to panic, the combination of candidate_clear_queue from the
+	/// when it was last active until the penultimate vote should result in no approvals.
+	///
+	/// May be called by anyone. Returns the voter deposit to `signed`.
+	pub fn kill_inactive_voter(signed: &AccountId, who: &AddressId) {
+		unimplemented!();
+	}
+
+	/// Remove a voter. All votes are cancelled and the voter deposit is returned.
+	pub fn retract_voter(signed: AccountId) {
+		unimplemented!();
+	}
+
+	/// Submit oneself for candidacy.
+	///
+	/// Account must have enough cash in it to pay the bond.
+	pub fn submit_candidacy(signed: &AccountId) {
+		unimplemented!();
+	}
+
+	/// Claim that `signed` is one of the top carry_count() + current_vote().1 candidates.
+	/// Only works if the block number >= current_vote().0 and < current_vote().0 + presentation_duration()
+	pub fn present(signed: &AccountId) {
+		unimplemented!();
+	}
+}
+
+pub mod privileged {
+	use super::*;
+
+	/// Set the desired member count; if lower than the current count, then seats will not be up
+	/// election when they expire. If more, then a new vote will be started if one is not already
+	/// in progress.
+	pub fn set_desired_seats(count: u32) {
+		unimplemented!();
+	}
+
+	/// Remove a particular member. A new vote will be started if one is not already in progress.
+	/// This is effective immediately.
+	pub fn remove_member(who: AddressId) {
+		unimplemented!();
+	}
+}
+
+pub mod internal {
+	use super::*;
+	use demo_primitives::Proposal;
+	use dispatch::enact_proposal;
+
+	/// Current era is ending; we should finish up any proposals.
+	pub fn end_block() {
+		if let Some((number, removals)) = current_vote() {
+			if system::block_number() == number {
+				close_voting(removals.len() as u32);
+			}
+			if system::block_number() == number + presentation_duration() {
+				finalise_vote(removals);
+			}
+		}
+	}
+}
+
+/// Close the voting, snapshot the staking and the number of seats that are actually up for grabs.
+fn close_voting(removal_count: u32) {
+	unimplemented!();
+}
+
+/// Finalise the vote, removing each of the `removals` and inserting `seats` of the most approved
+/// candidates in their place. If the total council members is less than the desired membership
+/// a new vote is started.
+/// Clears all presented candidates, returning the bond of the elected ones.
+fn finalise_vote(seats: u32, removals: Vec<AccountId>) {
+	unimplemented!();
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use runtime_io::{with_externalities, twox_128, TestExternalities};
+	use codec::{KeyedVec, Joiner};
+	use keyring::Keyring;
+	use environment::with_env;
+	use demo_primitives::{AccountId, Proposal};
+	use runtime::{staking, session, democracy};
+
+	fn new_test_ext() -> TestExternalities {
+		let alice = Keyring::Alice.to_raw_public();
+		let bob = Keyring::Bob.to_raw_public();
+		let charlie = Keyring::Charlie.to_raw_public();
+		let dave = Keyring::Dave.to_raw_public();
+		let eve = Keyring::Eve.to_raw_public();
+		let ferdie = Keyring::Ferdie.to_raw_public();
+		let one = Keyring::One.to_raw_public();
+
+		map![
+			twox_128(b"ses:len").to_vec() => vec![].and(&1u64),
+			twox_128(b"ses:val:len").to_vec() => vec![].and(&3u32),
+			twox_128(&0u32.to_keyed_vec(b"ses:val:")).to_vec() => alice.to_vec(),
+			twox_128(&1u32.to_keyed_vec(b"ses:val:")).to_vec() => bob.to_vec(),
+			twox_128(&2u32.to_keyed_vec(b"ses:val:")).to_vec() => charlie.to_vec(),
+			twox_128(b"sta:wil:len").to_vec() => vec![].and(&3u32),
+			twox_128(&0u32.to_keyed_vec(b"sta:wil:")).to_vec() => alice.to_vec(),
+			twox_128(&1u32.to_keyed_vec(b"sta:wil:")).to_vec() => bob.to_vec(),
+			twox_128(&2u32.to_keyed_vec(b"sta:wil:")).to_vec() => charlie.to_vec(),
+			twox_128(&alice.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&10u64),
+			twox_128(&bob.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&20u64),
+			twox_128(&charlie.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&30u64),
+			twox_128(&dave.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&40u64),
+			twox_128(&eve.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&50u64),
+			twox_128(&ferdie.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&60u64),
+			twox_128(&one.to_keyed_vec(b"sta:bal:")).to_vec() => vec![].and(&1u64),
+			twox_128(b"sta:tot").to_vec() => vec![].and(&210u64),
+			twox_128(b"sta:spe").to_vec() => vec![].and(&1u64),
+			twox_128(b"sta:vac").to_vec() => vec![].and(&3u64),
+			twox_128(b"sta:era").to_vec() => vec![].and(&1u64)
+		]
+	}
+
+	#[test]
+	fn simple_passing_should_work() {
+		let alice = Keyring::Alice.to_raw_public();
+		let mut t = new_test_ext();
+
+		with_externalities(&mut t, || {
+			assert_eq!(staking::era_length(), 1u64);
+			assert_eq!(staking::total_stake(), 210u64);
+
+			with_env(|e| e.block_number = 1);
+			public::propose(&alice, &Proposal::StakingSetSessionsPerEra(2));
+			public::vote(&alice, 1, true);
+
+			assert_eq!(public::tally(), (10, 0));
+
+			democracy::internal::end_of_an_era();
+			staking::internal::check_new_era();
+
+			assert_eq!(staking::era_length(), 2u64);
+		});
+	}
+}

substrate/demo/runtime/src/runtime/democracy.rs

@@ -23,9 +23,9 @@ use runtime_support::storage;
 use demo_primitives::{Proposal, AccountId, Hash, BlockNumber};
 use runtime::{staking, system, session};
 
-const CURRENT_PROPOSAL: &[u8] = b"gov:pro";
+const CURRENT_PROPOSAL: &[u8] = b"dem:pro";
-const VOTE_OF: &[u8] = b"gov:vot:";
+const VOTE_OF: &[u8] = b"dem:vot:";
-const VOTERS: &[u8] = b"gov:vtr:";
+const VOTERS: &[u8] = b"dem:vtr:";
 
 pub mod public {
 	use super::*;