remove BasisPoints and change relevant parameters to Decimal type

Author: brentstone

apps/src/lib/config/genesis.rs

@@ -29,14 +29,14 @@ pub mod genesis_config {
     use hex;
     use namada::ledger::governance::parameters::GovParams;
     use namada::ledger::parameters::{EpochDuration, Parameters};
-    use namada::ledger::pos::types::BasisPoints;
     use namada::ledger::pos::{GenesisValidator, PosParams};
     use namada::ledger::treasury::parameters::TreasuryParams;
     use namada::types::address::Address;
     use namada::types::key::dkg_session_keys::DkgPublicKey;
     use namada::types::key::*;
     use namada::types::time::Rfc3339String;
     use namada::types::{storage, token};
+    use rust_decimal::Decimal;
     use serde::{Deserialize, Serialize};
     use thiserror::Error;
 
@@ -265,24 +265,24 @@ pub mod genesis_config {
         pub unbonding_len: u64,
         // Votes per token (in basis points).
         // XXX: u64 doesn't work with toml-rs!
-        pub votes_per_token: u64,
+        pub votes_per_token: Decimal,
         // Reward for proposing a block.
         // XXX: u64 doesn't work with toml-rs!
-        pub block_proposer_reward: u64,
+        pub block_proposer_reward: Decimal,
         // Reward for voting on a block.
         // XXX: u64 doesn't work with toml-rs!
-        pub block_vote_reward: u64,
+        pub block_vote_reward: Decimal,
         // Maximum staking APY
         // XXX: u64 doesn't work with toml-rs!
-        pub max_staking_rewards_rate: u64,
+        pub max_staking_rewards_rate: Decimal,
         // Portion of a validator's stake that should be slashed on a
         // duplicate vote (in basis points).
         // XXX: u64 doesn't work with toml-rs!
-        pub duplicate_vote_slash_rate: u64,
+        pub duplicate_vote_slash_rate: Decimal,
         // Portion of a validator's stake that should be slashed on a
         // light client attack (in basis points).
         // XXX: u64 doesn't work with toml-rs!
-        pub light_client_attack_slash_rate: u64,
+        pub light_client_attack_slash_rate: Decimal,
     }
 
     #[derive(Clone, Debug, Deserialize, Serialize)]
@@ -569,20 +569,18 @@ pub mod genesis_config {
             max_validator_slots: config.pos_params.max_validator_slots,
             pipeline_len: config.pos_params.pipeline_len,
             unbonding_len: config.pos_params.unbonding_len,
-            votes_per_token: BasisPoints::new(
-                config.pos_params.votes_per_token,
-            ),
+            votes_per_token: config.pos_params.votes_per_token,
             block_proposer_reward: config.pos_params.block_proposer_reward,
             block_vote_reward: config.pos_params.block_vote_reward,
-            max_staking_rewards_rate: BasisPoints::new(
-                config.pos_params.max_staking_rewards_rate,
-            ),
-            duplicate_vote_slash_rate: BasisPoints::new(
-                config.pos_params.duplicate_vote_slash_rate,
-            ),
-            light_client_attack_slash_rate: BasisPoints::new(
-                config.pos_params.light_client_attack_slash_rate,
-            ),
+            max_staking_rewards_rate: config
+                .pos_params
+                .max_staking_rewards_rate,
+            duplicate_vote_slash_rate: config
+                .pos_params
+                .duplicate_vote_slash_rate,
+            light_client_attack_slash_rate: config
+                .pos_params
+                .light_client_attack_slash_rate,
         };
 
         let mut genesis = Genesis {

proof_of_stake/src/parameters.rs

@@ -1,10 +1,11 @@
 //! Proof-of-Stake system parameters
 
 use borsh::{BorshDeserialize, BorshSerialize};
+use rust_decimal::prelude::ToPrimitive;
+use rust_decimal::Decimal;
+use rust_decimal_macros::dec;
 use thiserror::Error;
 
-use crate::types::BasisPoints;
-
 /// Proof-of-Stake system parameters
 #[derive(Debug, Clone, BorshDeserialize, BorshSerialize)]
 pub struct PosParams {
@@ -20,20 +21,20 @@ pub struct PosParams {
     pub unbonding_len: u64,
     /// Used in validators' voting power calculation. Given in basis points
     /// (voting power per ten thousand tokens).
-    pub votes_per_token: BasisPoints,
+    pub votes_per_token: Decimal,
     /// Amount of tokens rewarded to a validator for proposing a block
-    pub block_proposer_reward: u64,
+    pub block_proposer_reward: Decimal,
     /// Amount of tokens rewarded to each validator that voted on a block
     /// proposal
-    pub block_vote_reward: u64,
+    pub block_vote_reward: Decimal,
     /// Maximum staking rewards rate per annum
-    pub max_staking_rewards_rate: BasisPoints,
+    pub max_staking_rewards_rate: Decimal,
     /// Portion of validator's stake that should be slashed on a duplicate
     /// vote. Given in basis points (slashed amount per ten thousand tokens).
-    pub duplicate_vote_slash_rate: BasisPoints,
+    pub duplicate_vote_slash_rate: Decimal,
     /// Portion of validator's stake that should be slashed on a light client
     /// attack. Given in basis points (slashed amount per ten thousand tokens).
-    pub light_client_attack_slash_rate: BasisPoints,
+    pub light_client_attack_slash_rate: Decimal,
 }
 
 impl Default for PosParams {
@@ -42,16 +43,17 @@ impl Default for PosParams {
             max_validator_slots: 128,
             pipeline_len: 2,
             unbonding_len: 6,
-            // 1 voting power per 1 fundamental token (10^6 per NAM or 1 per namnam)
-            votes_per_token: BasisPoints::new(10000),
-            block_proposer_reward: 100,
-            block_vote_reward: 1,
+            // 1 voting power per 1 fundamental token (10^6 per NAM or 1 per
+            // namnam)
+            votes_per_token: dec!(1.0),
+            block_proposer_reward: dec!(0.0625),
+            block_vote_reward: dec!(0.05),
             // staking APY 20%
-            max_staking_rewards_rate: BasisPoints::new(2000),
+            max_staking_rewards_rate: dec!(0.2),
             // slash 5%
-            duplicate_vote_slash_rate: BasisPoints::new(500),
+            duplicate_vote_slash_rate: dec!(0.05),
             // slash 5%
-            light_client_attack_slash_rate: BasisPoints::new(500),
+            light_client_attack_slash_rate: dec!(0.05),
         }
     }
 }
@@ -65,7 +67,7 @@ pub enum ValidationError {
     )]
     TotalVotingPowerTooLarge(u64),
     #[error("Votes per token cannot be greater than 1, got {0}")]
-    VotesPerTokenGreaterThanOne(BasisPoints),
+    VotesPerTokenGreaterThanOne(Decimal),
     #[error("Pipeline length must be >= 2, got {0}")]
     PipelineLenTooShort(u64),
     #[error(
@@ -105,8 +107,8 @@ impl PosParams {
 
         // Check maximum total voting power cannot get larger than what
         // Tendermint allows
-        let max_total_voting_power = self.max_validator_slots
-            * (self.votes_per_token * TOKEN_MAX_AMOUNT);
+        let max_total_voting_power = Decimal::from(self.max_validator_slots)
+            * self.votes_per_token * Decimal::from(TOKEN_MAX_AMOUNT);
         match i64::try_from(max_total_voting_power) {
             Ok(max_total_voting_power_i64) => {
                 if max_total_voting_power_i64 > MAX_TOTAL_VOTING_POWER {
@@ -121,7 +123,7 @@ impl PosParams {
         }
 
         // Check that there is no more than 1 vote per token
-        if self.votes_per_token > BasisPoints::new(10_000) {
+        if self.votes_per_token > dec!(1.0) {
             errors.push(ValidationError::VotesPerTokenGreaterThanOne(
                 self.votes_per_token,
             ))
@@ -174,7 +176,7 @@ pub mod testing {
                 max_validator_slots,
                 pipeline_len,
                 unbonding_len,
-                votes_per_token: BasisPoints::new(votes_per_token),
+                votes_per_token: Decimal::from(votes_per_token) / dec!(10_000),
                 // The rest of the parameters that are not being used in the PoS
                 // VP are constant for now
                 ..Default::default()

proof_of_stake/src/rewards.rs

@@ -1,6 +1,7 @@
 //! PoS rewards
 
 use rust_decimal::Decimal;
+use rust_decimal_macros::dec;
 use thiserror::Error;
 
 use crate::types::VotingPower;
@@ -29,20 +30,20 @@ pub struct PosRewards {
 /// bing
 #[derive(Debug, Copy, Clone)]
 pub struct PosRewardsCalculator {
-    proposer_param: u64,
-    signer_param: u64,
     signing_stake: VotingPower,
     total_stake: VotingPower,
+    proposer_param: Decimal,
+    signer_param: Decimal,
     pos_rewards: Option<PosRewards>,
 }
 
 impl PosRewardsCalculator {
     /// new
     pub fn new(
-        proposer_param: u64,
-        signer_param: u64,
         signing_stake: VotingPower,
         total_stake: VotingPower,
+        proposer_param: Decimal,
+        signer_param: Decimal,
     ) -> Self {
         Self {
             proposer_param,

proof_of_stake/src/types.rs

@@ -6,9 +6,11 @@ use std::convert::TryFrom;
 use std::fmt::Display;
 use std::hash::Hash;
 use std::num::TryFromIntError;
-use std::ops::{Add, AddAssign, Mul, Sub, SubAssign};
+use std::ops::{Add, AddAssign, Sub, SubAssign};
 
 use borsh::{BorshDeserialize, BorshSchema, BorshSerialize};
+use rust_decimal::prelude::ToPrimitive;
+use rust_decimal::Decimal;
 
 use crate::epoched::{
     Epoched, EpochedDelta, OffsetPipelineLen, OffsetUnbondingLen,
@@ -324,7 +326,7 @@ pub struct Slash {
     /// A type of slashsable event.
     pub r#type: SlashType,
     /// A rate is the portion of staked tokens that are slashed.
-    pub rate: BasisPoints,
+    pub rate: Decimal,
 }
 
 /// Slashes applied to validator, to punish byzantine behavior by removing
@@ -362,23 +364,6 @@ impl From<tendermint_proto::abci::VoteInfo> for VoteInfo {
     }
 }
 
-/// ‱ (Parts per ten thousand). This can be multiplied by any type that
-/// implements [`Into<u64>`] or [`Into<i128>`].
-#[derive(
-    Debug,
-    Clone,
-    Copy,
-    BorshDeserialize,
-    BorshSerialize,
-    BorshSchema,
-    PartialOrd,
-    Ord,
-    PartialEq,
-    Eq,
-    Hash,
-)]
-pub struct BasisPoints(u64);
-
 /// Derive Tendermint raw hash from the public key
 pub trait PublicKeyTmRawHash {
     /// Derive Tendermint raw hash from the public key
@@ -737,7 +722,7 @@ where
 impl SlashType {
     /// Get the slash rate applicable to the given slash type from the PoS
     /// parameters.
-    pub fn get_slash_rate(&self, params: &PosParams) -> BasisPoints {
+    pub fn get_slash_rate(&self, params: &PosParams) -> Decimal {
         match self {
             SlashType::DuplicateVote => params.duplicate_vote_slash_rate,
             SlashType::LightClientAttack => {
@@ -756,35 +741,8 @@ impl Display for SlashType {
     }
 }
 
-impl BasisPoints {
-    /// Initialize basis points from an integer.
-    pub fn new(value: u64) -> Self {
-        Self(value)
-    }
-}
-
-impl Display for BasisPoints {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}‱", self.0)
-    }
-}
-
-impl Mul<u64> for BasisPoints {
-    type Output = u64;
-
-    fn mul(self, rhs: u64) -> Self::Output {
-        // TODO checked arithmetics
-        rhs * self.0 / 10_000
-    }
 }
 
-impl Mul<i128> for BasisPoints {
-    type Output = i128;
-
-    fn mul(self, rhs: i128) -> Self::Output {
-        // TODO checked arithmetics
-        rhs * self.0 as i128 / 10_000
-    }
 }
 
 #[cfg(test)]