fix(solc): empty 'Solc error: ' message

ethers-solc/src/cache.rs

@@ -459,7 +459,7 @@ impl CacheEntry {
             .modified()
             .map_err(|err| SolcError::io(err, file.to_path_buf()))?
             .duration_since(UNIX_EPOCH)
-            .map_err(|err| SolcError::solc(err.to_string()))?
+            .map_err(SolcError::msg)?
             .as_millis() as u64;
         Ok(last_modification_date)
     }

ethers-solc/src/compile/mod.rs

@@ -8,7 +8,6 @@ use semver::{Version, VersionReq};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 use std::{
     fmt,
-    io::BufRead,
     path::{Path, PathBuf},
     process::{Command, Output, Stdio},
     str::FromStr,
@@ -300,7 +299,7 @@ impl Solc {
     pub fn find_svm_installed_version(version: impl AsRef<str>) -> Result<Option<Self>> {
         let version = version.as_ref();
         let solc = Self::svm_home()
-            .ok_or_else(|| SolcError::solc("svm home dir not found"))?
+            .ok_or_else(|| SolcError::msg("svm home dir not found"))?
             .join(version)
             .join(format!("solc-{version}"));
 
@@ -710,23 +709,22 @@ fn compile_output(output: Output) -> Result<Vec<u8>> {
     if output.status.success() {
         Ok(output.stdout)
     } else {
-        Err(SolcError::solc(String::from_utf8_lossy(&output.stderr).to_string()))
+        Err(SolcError::solc_output(&output))
     }
 }
 
 fn version_from_output(output: Output) -> Result<Version> {
     if output.status.success() {
-        let version = output
-            .stdout
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        let version = stdout
             .lines()
-            .map_while(std::result::Result::ok)
             .filter(|l| !l.trim().is_empty())
             .last()
-            .ok_or_else(|| SolcError::solc("version not found in solc output"))?;
+            .ok_or_else(|| SolcError::msg("Version not found in Solc output"))?;
         // NOTE: semver doesn't like `+` in g++ in build metadata which is invalid semver
         Ok(Version::from_str(&version.trim_start_matches("Version: ").replace(".g++", ".gcc"))?)
     } else {
-        Err(SolcError::solc(String::from_utf8_lossy(&output.stderr).to_string()))
+        Err(SolcError::solc_output(&output))
     }
 }
 

ethers-solc/src/error.rs

@@ -10,9 +10,9 @@ pub type Result<T> = std::result::Result<T, SolcError>;
 /// Various error types
 #[derive(Debug, Error)]
 pub enum SolcError {
-    /// Internal solc error
-    #[error("Solc Error: {0}")]
-    SolcError(String),
+    /// Errors related to the Solc executable itself.
+    #[error("Solc exited with {0}: {1}")]
+    SolcError(std::process::ExitStatus, String),
     #[error("Missing pragma from solidity file")]
     PragmaNotFound,
     #[error("Could not find solc version locally or upstream")]
@@ -49,7 +49,7 @@ pub enum SolcError {
     NoContracts(String),
     #[error(transparent)]
     PatternError(#[from] glob::PatternError),
-    /// General purpose message
+    /// General purpose message.
     #[error("{0}")]
     Message(String),
 
@@ -65,11 +65,24 @@ impl SolcError {
     pub(crate) fn io(err: io::Error, path: impl Into<PathBuf>) -> Self {
         SolcIoError::new(err, path).into()
     }
-    pub(crate) fn solc(msg: impl Into<String>) -> Self {
-        SolcError::SolcError(msg.into())
+
+    /// Create an error from the Solc executable's output.
+    pub(crate) fn solc_output(output: &std::process::Output) -> Self {
+        let mut msg = String::from_utf8_lossy(&output.stderr);
+        let mut trimmed = msg.trim();
+        if trimmed.is_empty() {
+            msg = String::from_utf8_lossy(&output.stdout);
+            trimmed = msg.trim();
+            if trimmed.is_empty() {
+                trimmed = "<empty output>";
+            }
+        }
+        SolcError::SolcError(output.status, trimmed.into())
     }
-    pub fn msg(msg: impl Into<String>) -> Self {
-        SolcError::Message(msg.into())
+
+    /// General purpose message.
+    pub fn msg(msg: impl std::fmt::Display) -> Self {
+        SolcError::Message(msg.to_string())
     }
 }