Merge remote-tracking branch 'origin/brent/remove-f64' into pos-integ…

…ration

* origin/brent/remove-f64:
  changelog: #436
  [ci] wasm checksums update
  replace floating point arithm from token module with rust_decimal

.changelog/unreleased/improvements/436-remove-f64.md

@@ -0,0 +1,2 @@
+- Refactored token decimal formatting.
+  ([#436](https://github.com/anoma/namada/pull/436))

proof_of_stake/src/parameters.rs

@@ -71,11 +71,14 @@ pub enum ValidationError {
     UnbondingLenTooShort(u64, u64),
 }
 
+/// The number of fundamental units per whole token of the native staking token
+pub const TOKENS_PER_NAM: u64 = 1_000_000;
+
 /// From Tendermint: <https://github.com/tendermint/tendermint/blob/master/spec/abci/apps.md#updating-the-validator-set>
 const MAX_TOTAL_VOTING_POWER: i64 = i64::MAX / 8;
 
 /// Assuming token amount is `u64` in micro units.
-const TOKEN_MAX_AMOUNT: u64 = u64::MAX / 1_000_000;
+const TOKEN_MAX_AMOUNT: u64 = u64::MAX / TOKENS_PER_NAM;
 
 impl PosParams {
     /// Validate PoS parameters values. Returns an empty list if the values are

shared/src/types/token.rs

@@ -6,6 +6,7 @@ use std::ops::{Add, AddAssign, Mul, Sub, SubAssign};
 use std::str::FromStr;
 
 use borsh::{BorshDeserialize, BorshSchema, BorshSerialize};
+use rust_decimal::prelude::{Decimal, ToPrimitive};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -37,7 +38,6 @@ pub struct Amount {
 pub const MAX_DECIMAL_PLACES: u32 = 6;
 /// Decimal scale of token [`Amount`] and [`Change`].
 pub const SCALE: u64 = 1_000_000;
-const SCALE_F64: f64 = SCALE as f64;
 
 /// A change in tokens amount
 pub type Change = i128;
@@ -109,21 +109,16 @@ impl<'de> serde::Deserialize<'de> for Amount {
     }
 }
 
-impl From<Amount> for f64 {
-    /// Warning: `f64` loses precision and it should not be used when exact
-    /// values are required.
+impl From<Amount> for Decimal {
     fn from(amount: Amount) -> Self {
-        amount.micro as f64 / SCALE_F64
+        Into::<Decimal>::into(amount.micro) / Into::<Decimal>::into(SCALE)
     }
 }
 
-impl From<f64> for Amount {
-    /// Warning: `f64` loses precision and it should not be used when exact
-    /// values are required.
-    fn from(micro: f64) -> Self {
-        Self {
-            micro: (micro * SCALE_F64).round() as u64,
-        }
+impl From<Decimal> for Amount {
+    fn from(micro: Decimal) -> Self {
+        let res = (micro * Into::<Decimal>::into(SCALE)).to_u64().unwrap();
+        Self { micro: res }
     }
 }
 
@@ -205,7 +200,7 @@ impl FromStr for Amount {
         match rust_decimal::Decimal::from_str(s) {
             Ok(decimal) => {
                 let scale = decimal.scale();
-                if scale > 6 {
+                if scale > MAX_DECIMAL_PLACES {
                     return Err(AmountParseError::ScaleTooLarge(scale));
                 }
                 let whole =
@@ -440,11 +435,11 @@ mod tests {
             /// The upper limit is set to `2^51`, because then the float is
             /// starting to lose precision.
             #[test]
-            fn test_token_amount_f64_conversion(raw_amount in 0..2_u64.pow(51)) {
+            fn test_token_amount_decimal_conversion(raw_amount in 0..2_u64.pow(51)) {
                 let amount = Amount::from(raw_amount);
-                // A round-trip conversion to and from f64 should be an identity
-                let float = f64::from(amount);
-                let identity = Amount::from(float);
+                // A round-trip conversion to and from Decimal should be an identity
+                let decimal = Decimal::from(amount);
+                let identity = Amount::from(decimal);
                 assert_eq!(amount, identity);
         }
     }

tests/src/native_vp/pos.rs

@@ -594,6 +594,10 @@ pub mod testing {
 
     use crate::tx::{self, tx_host_env};
 
+    const TOKENS_PER_NAM: i128 =
+        namada::ledger::pos::namada_proof_of_stake::parameters::TOKENS_PER_NAM
+            as i128;
+
     #[derive(Clone, Debug, Default)]
     pub struct TestValidator {
         pub address: Option<Address>,
@@ -940,9 +944,9 @@ pub mod testing {
                     // We convert the tokens from micro units to whole tokens
                     // with division by 10^6
                     let vp_before =
-                        params.votes_per_token * ((total_delta) / 1_000_000);
+                        params.votes_per_token * (total_delta / TOKENS_PER_NAM);
                     let vp_after = params.votes_per_token
-                        * ((total_delta + token_delta) / 1_000_000);
+                        * ((total_delta + token_delta) / TOKENS_PER_NAM);
                     // voting power delta
                     let vp_delta = vp_after - vp_before;
 
@@ -1001,12 +1005,12 @@ pub mod testing {
                         let total_delta = validator_total_deltas
                             .get(epoch)
                             .unwrap_or_default();
-                        // We convert the tokens from micro units to whole
+                        // We convert the tokens from micro units to whole 
                         // tokens with division by 10^6
                         let vp_before = params.votes_per_token
-                            * ((total_delta) / 1_000_000);
+                            * (total_delta / TOKENS_PER_NAM);
                         let vp_after = params.votes_per_token
-                            * ((total_delta + token_delta) / 1_000_000);
+                            * ((total_delta + token_delta) / TOKENS_PER_NAM);
                         // voting power delta
                         let vp_delta_at_unbonding =
                             vp_after - vp_before - vp_delta - total_vp_delta;
@@ -1080,9 +1084,9 @@ pub mod testing {
                     // We convert the tokens from micro units to whole tokens
                     // with division by 10^6
                     let vp_before = params.votes_per_token
-                        * ((total_delta_cur) / 1_000_000);
+                        * (total_delta_cur / TOKENS_PER_NAM);
                     let vp_after = params.votes_per_token
-                        * ((total_delta_cur + token_delta) / 1_000_000);
+                        * ((total_delta_cur + token_delta) / TOKENS_PER_NAM);
                     // voting power delta
                     let vp_delta = vp_after - vp_before;
 

wasm/checksums.json

@@ -1,15 +1,15 @@
 {
-    "tx_bond.wasm": "tx_bond.e19c3845447cac4ca90b17fdc7d12428afca654b26f8c7d08475a87d7fa1627f.wasm",
-    "tx_ibc.wasm": "tx_ibc.dc153eadbb7e11bc80491f818060a9ee6d4c9ff1d73dfc8fc725c70545224c97.wasm",
-    "tx_init_account.wasm": "tx_init_account.d0163b28bcd3863935f080742a89758f2b6b19ca63e5f62c0730ef59ef07aecc.wasm",
-    "tx_init_proposal.wasm": "tx_init_proposal.26e6e564222920bec2790140d9e71d6baa2ae2e932c7a974db628e9c370c0604.wasm",
-    "tx_init_validator.wasm": "tx_init_validator.fc728de452311fc28c89d6f2e42f42034422d12a5a57248bcc0317598da098b0.wasm",
-    "tx_transfer.wasm": "tx_transfer.c5272f6d5b17f4466cd66246f037646c4ef1cf1fc9f51d4855dbcf346fc6cc6f.wasm",
-    "tx_unbond.wasm": "tx_unbond.ff803f73eee8585a3a31ad9c6ca84579ed5e4a519214d1634efb7799a5f73d1d.wasm",
-    "tx_update_vp.wasm": "tx_update_vp.94ea72ce2052394b3d03ce1de168a7c0e8d2c9b63c2432cd279ad5d7eb4956b1.wasm",
-    "tx_vote_proposal.wasm": "tx_vote_proposal.ed220b8b090dc029e1ed30024f27c0d4527a785994eba44b7a0b17baf72cb82c.wasm",
-    "tx_withdraw.wasm": "tx_withdraw.72248dcad1caf3063d8a7c80ccb1080069212bc65aefc26546ec61d33d820e22.wasm",
-    "vp_testnet_faucet.wasm": "vp_testnet_faucet.bdea8acbcaff11d90e6dd3e0588aba64c2836e45f151886f22fd55e8d689e658.wasm",
-    "vp_token.wasm": "vp_token.ce12c276d47ec44569a4dc32af6f6c9226f01587ec7ff5037edb12e3ba9af763.wasm",
-    "vp_user.wasm": "vp_user.58eacd2d8d8dbb7bddb210e27cc28f1cf1f386943258f35ca35862b7ce5e5b90.wasm"
+    "tx_bond.wasm": "tx_bond.973b43b3ec59d559ad0caf05ec29b9c859022084d96fc02b951d27ee45941379.wasm",
+    "tx_ibc.wasm": "tx_ibc.82e789f249e37005cd6f3e565897d42c0516413092b5e6db01b5b5a9ffdf2283.wasm",
+    "tx_init_account.wasm": "tx_init_account.4eb2ae9ef7b5df5d7b224b666fb1a1d6c4556dd8f88b8e7fc118e26c63fb3e95.wasm",
+    "tx_init_proposal.wasm": "tx_init_proposal.8625baf54979720e3ef7bc4b7c809b8d43c8e23b65b54ac640708db903dc6176.wasm",
+    "tx_init_validator.wasm": "tx_init_validator.9a6111478ee6d7e6c178d979ef4bee164132db309802d25382867388fcbf7ae1.wasm",
+    "tx_transfer.wasm": "tx_transfer.a1b6a5682606a258f4f6fd0503ceb999acbef63530c5e72a924ae5c0c8f835f1.wasm",
+    "tx_unbond.wasm": "tx_unbond.84c83cf42252ee2d783664122fdda93ab2a7aab9e86d27615ffeb17f7ed8e7e3.wasm",
+    "tx_update_vp.wasm": "tx_update_vp.5397ef094da377fbfdb1002ff63ad85ada77754b4c17f6cd74acc34c4b24b6cd.wasm",
+    "tx_vote_proposal.wasm": "tx_vote_proposal.14dbe6186029858a325a1e4212e8d24a764afd09ea21bce067ff607aad0ec6b5.wasm",
+    "tx_withdraw.wasm": "tx_withdraw.4b099dc1e0969672b8dd53573c6839f9b450321d415e2675ef5bef3ab0d56f0f.wasm",
+    "vp_testnet_faucet.wasm": "vp_testnet_faucet.c825297e6835841c11978c7f5da9b7e1795e4a8f4065836c36eb147a34f1d8a9.wasm",
+    "vp_token.wasm": "vp_token.1fc42a09e0908ba5d6efcd536463348821dddbf573f2fffdd70d19923e63676b.wasm",
+    "vp_user.wasm": "vp_user.0a9ad2b746114525ba48ddc2be2bf8892e56a17c3a1924de03ed5d07dd56d75f.wasm"
 }