fix(solc): add timeout and error detection for releases lookup (#759)

* fix(solc): add timeout and error detection for releases lookup

* bump tokio cargo update

* fix: move timeout in async block

Cargo.lock

@@ -3419,11 +3419,10 @@ checksum = "cda74da7e1a664f795bb1f8a87ec406fb89a02522cf6e50620d016add6dbbf5c"
 
 [[package]]
 name = "tokio"
-version = "1.14.0"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70e992e41e0d2fb9f755b37446f20900f64446ef54874f40a60c78f021ac6144"
+checksum = "fbbf1c778ec206785635ce8ad57fe52b3009ae9e0c9f574a728f3049d3e55838"
 dependencies = [
- "autocfg",
  "bytes",
  "libc",
  "memchr",
@@ -3439,9 +3438,9 @@ dependencies = [
 
 [[package]]
 name = "tokio-macros"
-version = "1.6.0"
+version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9efc1aba077437943f7515666aa2b882dfabfbfdf89c819ea75a8d6e9eaba5e"
+checksum = "b557f72f448c511a979e2564e55d74e6c4432fc96ff4f6241bc6bded342643b7"
 dependencies = [
  "proc-macro2",
  "quote",

ethers-solc/Cargo.toml

@@ -19,7 +19,7 @@ serde_json = "1.0.68"
 serde = { version = "1.0.130", features = ["derive"] }
 semver = "1.0.4"
 walkdir = "2.3.2"
-tokio = { version = "1.12.0", default-features = false, features = ["process", "io-util", "fs"],  optional = true }
+tokio = { version = "1.15.0", default-features = false, features = ["process", "io-util", "fs", "time"], optional = true }
 futures-util = { version = "^0.3", optional = true }
 once_cell = "1.8.0"
 regex = "1.5.4"
@@ -50,7 +50,7 @@ getrandom = { version = "0.2", features = ["js"] }
 criterion = { version = "0.3", features = ["async_tokio"] }
 pretty_assertions = "1.0.0"
 tempdir = "0.3.7"
-tokio = { version = "1.12.0", features = ["full"] }
+tokio = { version = "1.15.0", features = ["full"] }
 
 [[bench]]
 name = "compile_many"

ethers-solc/src/compile.rs

@@ -48,20 +48,33 @@ static LOCK: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
 #[cfg(all(feature = "svm", feature = "async"))]
 /// A list of upstream Solc releases, used to check which version
 /// we should download.
-pub static RELEASES: Lazy<(svm::Releases, Vec<Version>)> = Lazy::new(|| {
+/// The boolean value marks whether there was an error.
+pub static RELEASES: Lazy<(svm::Releases, Vec<Version>, bool)> = Lazy::new(|| {
     // Try to download the releases, if it fails default to empty
     match tokio::runtime::Runtime::new()
         .expect("could not create tokio rt to get remote releases")
-        // TODO: Can we make this future timeout at a small time amount so that
         // we do not degrade startup performance if the consumer has a weak network?
-        .block_on(svm::all_releases(svm::platform()))
-    {
-        Ok(releases) => {
+        // use a 3 sec timeout for the request which should still be fine for slower connections
+        .block_on(async {
+            tokio::time::timeout(
+                std::time::Duration::from_millis(3000),
+                svm::all_releases(svm::platform()),
+            )
+            .await
+        }) {
+        Ok(Ok(releases)) => {
             let mut sorted_releases = releases.releases.keys().cloned().collect::<Vec<Version>>();
             sorted_releases.sort();
-            (releases, sorted_releases)
+            (releases, sorted_releases, true)
+        }
+        Ok(Err(err)) => {
+            tracing::error!("{:?}", err);
+            (svm::Releases::default(), Vec::new(), false)
+        }
+        Err(err) => {
+            tracing::error!("Releases request timed out: {:?}", err);
+            (svm::Releases::default(), Vec::new(), false)
         }
-        Err(_) => (svm::Releases::default(), Vec::new()),
     }
 });
 
@@ -281,6 +294,12 @@ impl Solc {
         let content =
             std::fs::read(&version_path).map_err(|err| SolcError::io(err, version_path))?;
 
+        if !RELEASES.2 {
+            // we skip checksum verification because the underlying request to fetch release info
+            // failed so we have nothing to compare against
+            return Ok(())
+        }
+
         use sha2::Digest;
         let mut hasher = sha2::Sha256::new();
         hasher.update(&content);