feat(staking): discard nanoWits for power computation

This aims to reduce the chance for overflows

data_structures/src/staking/helpers.rs

@@ -16,7 +16,9 @@ use serde::{
     Deserialize, Deserializer, Serialize, Serializer,
 };
 
-use crate::{chain::PublicKeyHash, proto::ProtobufConvert, staking::prelude::*};
+use crate::{
+    chain::PublicKeyHash, proto::ProtobufConvert, staking::prelude::*, wit::PrecisionLoss,
+};
 
 /// Just a type alias for consistency of using the same data type to represent power.
 pub type Power = u64;
@@ -227,6 +229,7 @@ where
         + Mul<Output = Coins>
         + Mul<Epoch, Output = Power>
         + Ord
+        + PrecisionLoss
         + Send
         + Sub<Output = Coins>
         + Sum
@@ -274,6 +277,7 @@ where
         + Mul<Output = Coins>
         + Mul<Epoch, Output = Power>
         + Ord
+        + PrecisionLoss
         + Send
         + Sub<Output = Coins>
         + Sum

data_structures/src/staking/stake.rs

@@ -1,9 +1,11 @@
+use std::fmt::{Debug, Display};
 use std::{marker::PhantomData, ops::*};
 
 use serde::{Deserialize, Serialize};
 
+use crate::wit::{PrecisionLoss, WIT_DECIMAL_PLACES};
+
 use super::prelude::*;
-use std::fmt::{Debug, Display};
 
 /// A data structure that keeps track of a staker's staked coins and the epochs for different
 /// capabilities.
@@ -36,7 +38,8 @@ where
         + Debug
         + Display
         + Send
-        + Sync,
+        + Sync
+        + PrecisionLoss,
     Epoch: Copy
         + Default
         + num_traits::Saturating
@@ -106,7 +109,8 @@ where
     /// Derives the power of an identity in the network on a certain epoch from an entry. Most
     /// normally, the epoch is the current epoch.
     pub fn power(&self, capability: Capability, current_epoch: Epoch) -> Power {
-        self.coins * (current_epoch.saturating_sub(self.epochs.get(capability)))
+        self.coins.lose_precision(WIT_DECIMAL_PLACES)
+            * (current_epoch.saturating_sub(self.epochs.get(capability)))
     }
 
     /// Remove a certain amount of staked coins.

data_structures/src/staking/stakes.rs

@@ -13,7 +13,7 @@ use crate::{
     chain::PublicKeyHash,
     get_environment,
     transaction::{StakeTransaction, UnstakeTransaction},
-    wit::Wit,
+    wit::{PrecisionLoss, Wit},
 };
 
 use super::prelude::*;
@@ -106,7 +106,8 @@ where
         + Send
         + Sync
         + Display
-        + Sum,
+        + Sum
+        + PrecisionLoss,
     Epoch: Copy
         + Default
         + Saturating
@@ -313,11 +314,17 @@ where
         }
     }
 
+    /// Creates an instance of `Stakes` that is initialized with a existing set of stake entries.
+    ///
+    /// This is specially convenient after loading stakes from storage, as this function rebuilds
+    /// all the indexes at once to preserve write locks and reference counts.
     pub fn with_entries(
         entries: BTreeMap<StakeKey<Address>, SyncStake<Address, Coins, Epoch, Power>>,
     ) -> Self {
-        let mut stakes = Stakes::default();
-        stakes.by_key = entries;
+        let mut stakes = Stakes {
+            by_key: entries,
+            ..Default::default()
+        };
         stakes.reindex();
 
         stakes

data_structures/src/wit.rs

@@ -151,6 +151,22 @@ impl Sum for Wit {
     }
 }
 
+pub trait PrecisionLoss: Copy {
+    fn lose_precision(self, digits: u8) -> Self;
+}
+
+impl PrecisionLoss for u64 {
+    fn lose_precision(self, digits: u8) -> u64 {
+        self / 10_u64.pow(digits as u32)
+    }
+}
+
+impl PrecisionLoss for Wit {
+    fn lose_precision(self, digits: u8) -> Wit {
+        Wit(self.0.lose_precision(digits))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

node/src/actors/chain_manager/mod.rs

@@ -3568,7 +3568,7 @@ mod tests {
         dr_pool.process_commit(&co_tx, &Hash::default()).unwrap();
         dr_pool.process_commit(&co_tx2, &Hash::default()).unwrap();
         dr_pool.process_commit(&co_tx3, &Hash::default()).unwrap();
-        dr_pool.update_data_request_stages(None);
+        dr_pool.update_data_request_stages(None, None);
         dr_pool.process_reveal(&re_tx1, &Hash::default()).unwrap();
         dr_pool.process_reveal(&re_tx2, &Hash::default()).unwrap();
 

validations/src/eligibility/current.rs

@@ -3,7 +3,8 @@ use std::{
     iter::Sum,
     ops::{Add, Div, Mul, Sub},
 };
-use witnet_data_structures::staking::prelude::*;
+
+use witnet_data_structures::{staking::prelude::*, wit::PrecisionLoss};
 
 const MINING_REPLICATION_FACTOR: usize = 4;
 const WITNESSING_MAX_ROUNDS: usize = 4;
@@ -109,6 +110,7 @@ where
         + Sub<Output = Coins>
         + Mul
         + Mul<Epoch, Output = Power>
+        + PrecisionLoss
         + Sync
         + Send
         + Sum