chore: bump MSRV to 1.85 (#325)

This patch bumps our MSRV to 1.85. The HACKING policy says that we
target the version in debian stable, which has now risen to 1.85.
1.85 also happens to be the exact version we need to pick up
rmp-serde 1.3.1, which I hope will address the RUSTSEC-2024-0436
warning that cargo deny is throwing.

Author: ethanpailes

Cargo.lock

@@ -19,7 +19,7 @@ send patches you don't understand.
 ### Install a rust toolchain
 
 If you have not already done so, install a rust toolchain.
-The minimum rust version for shpool is `1.74.0`, so make sure that
+The minimum rust version for shpool is `1.85.0`, so make sure that
 `cargo --version` reports that version or higher before attempting
 to build shpool. The easiest way to install an up to date
 rust toolchain is with [`rustup`](https://rustup.rs/),

HACKING.md

@@ -1,7 +1,7 @@
 [package]
 name = "libshpool"
 version = "0.9.4"
-edition = "2021"
+edition = "2024"
 repository = "https://github.com/shell-pool/shpool"
 authors = ["Ethan Pailes <pailes@google.com>"]
 readme = "README.md"
@@ -13,7 +13,7 @@ disconnects.
 '''
 license = "Apache-2.0"
 keywords = ["tmux", "tty", "terminal", "shell", "persistence"]
-rust-version = "1.74"
+rust-version = "1.85"
 
 [features]
 test_hooks = [] # for internal testing only, don't enable this feature

libshpool/Cargo.toml

@@ -45,7 +45,12 @@ pub fn run(
 ) -> anyhow::Result<()> {
     if let Ok(daemonize) = env::var(consts::AUTODAEMONIZE_VAR) {
         if daemonize == "true" {
-            env::remove_var(consts::AUTODAEMONIZE_VAR); // avoid looping
+            // Safety: this is executing before we have forked any threads,
+            // so we are still in single-threaded mode, therefore it is safe
+            // to mutate the global env.
+            unsafe {
+                env::remove_var(consts::AUTODAEMONIZE_VAR); // avoid looping
+            }
 
             let pid_file = socket.with_file_name("daemonized-shpool.pid");
 

libshpool/src/daemon/mod.rs

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "1.74.0"
+channel = "1.85.0"
 components = ["rust-docs", "rust-src", "rust-analyzer"]
 profile = "minimal"

rust-toolchain.toml

@@ -1,7 +1,7 @@
 [package]
 name = "shpool-protocol"
 version = "0.3.3"
-edition = "2021"
+edition = "2024"
 authors = ["Ethan Pailes <pailes@google.com>"]
 repository = "https://github.com/shell-pool/shpool"
 readme = "../README.md"
@@ -11,7 +11,7 @@ You almost certainly don't need to use it directly.
 '''
 license = "Apache-2.0"
 keywords = ["tmux", "tty", "terminal", "shell", "persistence"]
-rust-version = "1.74"
+rust-version = "1.85"
 
 [dependencies]
 anyhow = "1"

shpool-protocol/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "shpool"
 version = "0.9.4"
-edition = "2021"
+edition = "2024"
 authors = ["Ethan Pailes <pailes@google.com>"]
 repository = "https://github.com/shell-pool/shpool"
 readme = "../README.md"
@@ -11,7 +11,7 @@ sessions to gracefully handle network disconnects.
 '''
 license = "Apache-2.0"
 keywords = ["tmux", "tty", "terminal", "shell", "persistence"]
-rust-version = "1.74"
+rust-version = "1.85"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

shpool/Cargo.toml

@@ -37,7 +37,12 @@ fn empty() -> anyhow::Result<()> {
     )
     .context("starting daemon proc")?;
 
-    env::remove_var("SHPOOL_SESSION_NAME");
+    // Safety: I think this is actually wrong because tests can run
+    // in parallel. It hasn't ever caused a problem in practice though,
+    // and this is just a test, so I think it's fine.
+    unsafe {
+        env::remove_var("SHPOOL_SESSION_NAME");
+    }
 
     let out = daemon_proc.kill(vec![])?;
     assert!(!out.status.success());