Upgrade to Rust 1.68.0 (#4471)

* Update Rust to 1.68

* node: replace crossbeam-channel with std

* config.toml: add useful comment

Author: neysofu

.cargo/config.toml

@@ -1,3 +1,9 @@
 [alias]
 # Warnings create a lot of noise, we only print errors.
 check-clippy = "clippy --no-deps -- --allow warnings"
+
+# Can be safely removed once Cargo's sparse protocol (see
+# https://blog.rust-lang.org/2023/03/09/Rust-1.68.0.html#cargos-sparse-protocol)
+# becomes the default.
+[registries.crates-io]
+protocol = "sparse"

Cargo.lock

@@ -20,7 +20,6 @@ graphql-parser = "0.4.0"
 futures = { version = "0.3.1", features = ["compat"] }
 lazy_static = "1.2.0"
 url = "2.3.1"
-crossbeam-channel = "0.5.7"
 graph = { path = "../graph" }
 graph-core = { path = "../core" }
 graph-chain-arweave = { path = "../chain/arweave" }

node/Cargo.toml

@@ -561,7 +561,7 @@ async fn main() {
     // Periodically check for contention in the tokio threadpool. First spawn a
     // task that simply responds to "ping" requests. Then spawn a separate
     // thread to periodically ping it and check responsiveness.
-    let (ping_send, mut ping_receive) = mpsc::channel::<crossbeam_channel::Sender<()>>(1);
+    let (ping_send, mut ping_receive) = mpsc::channel::<std::sync::mpsc::SyncSender<()>>(1);
     graph::spawn(async move {
         while let Some(pong_send) = ping_receive.recv().await {
             let _ = pong_send.clone().send(());
@@ -570,14 +570,13 @@ async fn main() {
     });
     std::thread::spawn(move || loop {
         std::thread::sleep(Duration::from_secs(1));
-        let (pong_send, pong_receive) = crossbeam_channel::bounded(1);
+        let (pong_send, pong_receive) = std::sync::mpsc::sync_channel(1);
         if futures::executor::block_on(ping_send.clone().send(pong_send)).is_err() {
             debug!(contention_logger, "Shutting down contention checker thread");
             break;
         }
         let mut timeout = Duration::from_millis(10);
-        while pong_receive.recv_timeout(timeout)
-            == Err(crossbeam_channel::RecvTimeoutError::Timeout)
+        while pong_receive.recv_timeout(timeout) == Err(std::sync::mpsc::RecvTimeoutError::Timeout)
         {
             debug!(contention_logger, "Possible contention in tokio threadpool";
                                      "timeout_ms" => timeout.as_millis(),

node/src/main.rs

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.66.0"
+channel = "1.68.0"
 profile = "default"