feat(etherscan): lookup solc build metadata

ethers-etherscan/Cargo.toml

@@ -22,6 +22,7 @@ serde_json = { version = "1.0.64", default-features = false }
 serde-aux = { version = "3.0.1", default-features = false }
 thiserror = "1.0.31"
 tracing = "0.1.34"
+semver = "1.0.9"
 
 [dev-dependencies]
 tempfile = "3.3.0"

ethers-etherscan/src/errors.rs

@@ -33,4 +33,6 @@ pub enum EtherscanError {
     Unknown(String),
     #[error("Missing field: {0}")]
     Builder(String),
+    #[error("Missing solc version: {0}")]
+    MissingSolcVersion(String),
 }

ethers-etherscan/src/lib.rs

@@ -24,6 +24,7 @@ pub mod errors;
 pub mod gas;
 pub mod source_tree;
 pub mod transaction;
+pub mod utils;
 
 pub(crate) type Result<T> = std::result::Result<T, EtherscanError>;
 

ethers-etherscan/src/utils.rs

@@ -0,0 +1,56 @@
+use semver::Version;
+
+use crate::{EtherscanError, Result};
+
+static SOLC_BIN_LIST_URL: &str =
+    "https://raw.githubusercontent.com/ethereum/solc-bin/gh-pages/bin/list.txt";
+
+/// Given the compiler version  lookup the build metadata
+/// and return full semver
+/// i.e. `0.8.13` -> `0.8.13+commit.abaa5c0e`
+pub async fn lookup_compiler_version(version: &Version) -> Result<Version> {
+    let response = reqwest::get(SOLC_BIN_LIST_URL).await?.text().await?;
+    let version = format!("{}", version);
+    let v = response
+        .lines()
+        .find(|l| !l.contains("nightly") && l.contains(&version))
+        .map(|l| l.trim_start_matches("soljson-v").trim_end_matches(".js").to_owned())
+        .ok_or(EtherscanError::MissingSolcVersion(version))?;
+
+    Ok(v.parse().expect("failed to parse semver"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::run_at_least_duration;
+    use semver::{BuildMetadata, Prerelease};
+    use serial_test::serial;
+    use std::time::Duration;
+
+    #[tokio::test]
+    #[serial]
+    async fn can_lookup_compiler_version_build_metadata() {
+        run_at_least_duration(Duration::from_millis(250), async {
+            let v = Version::new(0, 8, 13);
+            let version = lookup_compiler_version(&v).await.unwrap();
+            assert_eq!(v.major, version.major);
+            assert_eq!(v.minor, version.minor);
+            assert_eq!(v.patch, version.patch);
+            assert_ne!(version.build, BuildMetadata::EMPTY);
+            assert_eq!(version.pre, Prerelease::EMPTY);
+        })
+        .await
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn errors_on_invalid_solc() {
+        run_at_least_duration(Duration::from_millis(250), async {
+            let v = Version::new(100, 0, 0);
+            let err = lookup_compiler_version(&v).await.unwrap_err();
+            assert!(matches!(err, EtherscanError::MissingSolcVersion(_)));
+        })
+        .await
+    }
+}