fix(bridge-withdrawer, cli)!: use decimals from erc20 contract (#1762)

## Summary Updates CLI and bridge withdrawer to read the decimals off the contract when it is an erc20, to get the accurate decimals to utilize during withdrawal. ## Background Previously it was assumed that all erc20 contracts would have 18 decimals this is not guaranteed. #1760 is a similar fix but relies on configuring the withdrawer correctly. This version automatically reads off of the contract instead if it is an erc20. ## Changes - Read decimals off contract if or fallback to native prevision. ## Testing Ran against Flame to ensure it gets decimals correct on 6 decimal contract + CI tests. ## Changelogs Changelogs updated. --------- Co-authored-by: Richard Janis Goldschmidt <[email protected]>
astriaorg · Oct 30, 2024 · ca72c64 · ca72c64
1 parent d9913bb
commit ca72c64
Show file tree

Hide file tree

Showing 6 changed files with 48 additions and 3 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/astria-bridge-contracts/CHANGELOG.md b/crates/astria-bridge-contracts/CHANGELOG.md
@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Read the provided contract's `decimals` function, falling back to a hardcoded
+  value of 18 if the call fails.
+  [#1762](https://github.com/astriaorg/astria/pull/1762)
+
 ### Added
 
 - Initial release.
diff --git a/crates/astria-bridge-contracts/Cargo.toml b/crates/astria-bridge-contracts/Cargo.toml
@@ -17,3 +17,4 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 tendermint = { workspace = true }
 thiserror = { workspace = true }
+tracing = { workspace = true, optional = true }
diff --git a/crates/astria-bridge-contracts/src/lib.rs b/crates/astria-bridge-contracts/src/lib.rs
@@ -37,6 +37,23 @@ use ethers::{
 };
 pub use generated::*;
 
+const NON_ERC20_CONTRACT_DECIMALS: u32 = 18u32;
+
+macro_rules! warn {
+    ($($tt:tt)*) => {
+        #[cfg(feature = "tracing")]
+        {
+            #![cfg_attr(
+                feature = "tracing",
+                expect(
+                    clippy::used_underscore_binding,
+                    reason = "underscore is needed to quiet `unused-variables` warning if `tracing` feature is not set",
+            ))]
+            ::tracing::warn!($($tt)*);
+        }
+    }
+}
+
 #[derive(Debug, thiserror::Error)]
 #[error(transparent)]
 pub struct BuildError(BuildErrorKind);
@@ -295,7 +312,25 @@ where
             .await
             .map_err(BuildError::call_base_chain_asset_precision)?;
 
-        let exponent = 18u32
+        let contract_decimals = {
+            let erc_20_contract = astria_bridgeable_erc20::AstriaBridgeableERC20::new(
+                contract_address,
+                provider.clone(),
+            );
+            match erc_20_contract.decimals().call().await {
+                Ok(decimals) => decimals.into(),
+                Err(_error) => {
+                    warn!(
+                        error = &_error as &dyn std::error::Error,
+                        "failed reading decimals from contract; assuming it is not an ERC20 \
+                         contract and falling back to `{NON_ERC20_CONTRACT_DECIMALS}`"
+                    );
+                    NON_ERC20_CONTRACT_DECIMALS
+                }
+            }
+        };
+
+        let exponent = contract_decimals
             .checked_sub(base_chain_asset_precision)
             .ok_or_else(|| BuildError::bad_divisor(base_chain_asset_precision))?;
 

diff --git a/crates/astria-bridge-withdrawer/Cargo.toml b/crates/astria-bridge-withdrawer/Cargo.toml
@@ -30,7 +30,9 @@ tokio = { workspace = true, features = ["macros", "rt-multi-thread", "signal"] }
 tokio-util = { workspace = true }
 tonic = { workspace = true }
 
-astria-bridge-contracts = { path = "../astria-bridge-contracts" }
+astria-bridge-contracts = { path = "../astria-bridge-contracts", features = [
+  "tracing",
+] }
 astria-build-info = { path = "../astria-build-info", features = ["runtime"] }
 astria-core = { path = "../astria-core", features = [
   "serde",

diff --git a/crates/astria-cli/Cargo.toml b/crates/astria-cli/Cargo.toml
@@ -20,7 +20,9 @@ serde_yaml = "0.9.25"
 termion = "4.0.3"
 tracing-subscriber = "0.3.18"
 
-astria-bridge-contracts = { path = "../astria-bridge-contracts" }
+astria-bridge-contracts = { path = "../astria-bridge-contracts", features = [
+  "tracing",
+] }
 astria-core = { path = "../astria-core", features = ["serde"] }
 
 clap = { workspace = true, features = ["derive", "env"] }