Merge branch 'brent/remove-f64' (#436)

* 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

@@ -7,6 +7,7 @@ use std::str::FromStr;
 
 use borsh::{BorshDeserialize, BorshSchema, BorshSerialize};
 use masp_primitives::transaction::Transaction;
+use rust_decimal::prelude::{Decimal, ToPrimitive};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -38,7 +39,6 @@ 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;
@@ -110,21 +110,16 @@ 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 }
     }
 }
 
@@ -227,7 +222,7 @@ 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 =
@@ -470,11 +465,11 @@ 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/e2e/ibc_tests.rs

@@ -695,7 +695,7 @@ fn transfer_token(
         ALBERT,
         &receiver,
         NAM,
-        &Amount::from(100000_f64),
+        &Amount::whole(100000),
         port_channel_id_a,
         None,
         None,
@@ -814,7 +814,7 @@ fn transfer_back(
         BERTHA,
         &receiver,
         NAM,
-        &Amount::from(50000_f64),
+        &Amount::whole(50000),
         port_channel_id_b,
         Some(sub_prefix),
         None,
@@ -873,7 +873,7 @@ fn transfer_timeout(
         ALBERT,
         &receiver,
         NAM,
-        &Amount::from(100000_f64),
+        &Amount::whole(100000),
         port_channel_id_a,
         None,
         Some(Duration::new(5, 0)),
@@ -918,7 +918,7 @@ fn transfer_timeout_on_close(
         BERTHA,
         &receiver,
         NAM,
-        &Amount::from(100000_f64),
+        &Amount::whole(100000),
         port_channel_id_b,
         None,
         None,
@@ -967,7 +967,7 @@ fn try_transfer_on_close(
         ALBERT,
         &receiver,
         NAM,
-        &Amount::from(100000_f64),
+        &Amount::whole(100000),
         port_channel_id_a,
         None,
         None,

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.06959b7b98f314dc338dfd064f455bba4a1073feb376548953202cb9914b02df.wasm",
-    "tx_ibc.wasm": "tx_ibc.df535cd260ff98e492a14406be62a9d56d42c42d165e8e052118acf41af2f6c0.wasm",
+    "tx_bond.wasm": "tx_bond.7bdd7bcc4cc1191546d3eaa01820d6f5cf4eb71735eafff1c4421f0d2e1f723d.wasm",
+    "tx_ibc.wasm": "tx_ibc.79779eb0a993632c0be997b72f500de68fa42f7c25d09f949999fc8013a808ca.wasm",
     "tx_init_account.wasm": "tx_init_account.8a7fcbea9d6f74eb7b59436a24b6d2846e7294029b209add9b57a7d71aafd929.wasm",
-    "tx_init_proposal.wasm": "tx_init_proposal.0fd3d58630358fd644c6467a3a4b1f78bb392bfadfe72d5564cb02fe467b22c7.wasm",
-    "tx_init_validator.wasm": "tx_init_validator.d4edc590cd2613b989003fe64bd96cb178d6ad1ee5caa251130334c6ccaa4996.wasm",
-    "tx_transfer.wasm": "tx_transfer.8c22c05837dfed33f291377c94ee6feac96200355013684d419b3f18f41cde44.wasm",
-    "tx_unbond.wasm": "tx_unbond.250076716cd7e88991c4bcfba759ea66134a005e06026f6452196f22fa6551c0.wasm",
-    "tx_update_vp.wasm": "tx_update_vp.99a29ce8e54b0252a962dfe84a6e404f1f83a25991ea361baedeb18f9f59a0d8.wasm",
-    "tx_vote_proposal.wasm": "tx_vote_proposal.baa03c2847e53122675d38384634baf811c564b1ec6e049103724a2913245334.wasm",
-    "tx_withdraw.wasm": "tx_withdraw.505c8f7181483e7f76d1c253c23958dfbb32b0c58b8d3676cb476ab794a87eee.wasm",
-    "vp_masp.wasm": "vp_masp.ae5ef6cd9718e23323a264e28b2da74ec52fa56c812b36fa48bb650eacb527a9.wasm",
+    "tx_init_proposal.wasm": "tx_init_proposal.1449056604bac3a63fc65076d6c6fc5305edcfeb3fdc4fc14f9b2b60918f882b.wasm",
+    "tx_init_validator.wasm": "tx_init_validator.f015f967260d78cfe04f6c81b8981be34c941bcaa912aa0e2a92979df1493414.wasm",
+    "tx_transfer.wasm": "tx_transfer.ca4c05c17cbab7cb856d7b56d220dd1189b3b1c24721392ec7a2ebcbfa3b2147.wasm",
+    "tx_unbond.wasm": "tx_unbond.e911e9e4072094fc90edf1edbd86c2a53deeed1c0b870696d7b643fa11829bc4.wasm",
+    "tx_update_vp.wasm": "tx_update_vp.a8593dcb7c3c7a6cfab8dccae3a3de37fe7a394111c1be7ac82afe91a0a04e9c.wasm",
+    "tx_vote_proposal.wasm": "tx_vote_proposal.3e90ca4d15da7ee35ba9a3a99cd856ef2b2696e141dcc2ef9a03eba41c4a45f6.wasm",
+    "tx_withdraw.wasm": "tx_withdraw.358d9d445b8d975b13d1b37ed87dd316045928bdc5013c964a50f606b81ac437.wasm",
+    "vp_masp.wasm": "vp_masp.b4eaaa09b374d098a2953fea201310e79758205f2ded90573dd29ec0a4d7fdda.wasm",
     "vp_testnet_faucet.wasm": "vp_testnet_faucet.bf7474247822663a744f84aa5f248c014ce49ecf93f213c0e4d498a716145399.wasm",
     "vp_token.wasm": "vp_token.eef6be5850d6b2ec91abd0e1a2e06976a4e3f7b7ec8f8bb5cff786f58957cf19.wasm",
     "vp_user.wasm": "vp_user.aa6eb1e0bd92bd4e5dc5ae1bd4b0e48494a64a6b071677c84a5d0fb7a97ee341.wasm"