Emit a build warning if the compiler may fail to build (#194)

This should be reverted when the latest nightly can build again

1 files changed, 53 insertions, 0 deletions

diff --git a/azalea-protocol/build.rs b/azalea-protocol/build.rs
new file mode 100644
index 00000000..e3bb9c3c
--- /dev/null
+++ b/azalea-protocol/build.rs
@@ -0,0 +1,53 @@
+use std::env;
+use std::process::Command;
+
+/// The maximum recommended toolchain version, as a triple.
+const TOOLCHAIN_MAX: (u32, u32, u32) = (2024, 11, 11);
+
+fn main() {
+    if let Some(toolchain) = toolchain_version() {
+        // If the toolchain is not nightly, do nothing
+        if !toolchain.contains("nightly") {
+            return;
+        }
+
+        // Warn if the toolchain may cause issues
+        if !recommended_toolchain(&toolchain).unwrap_or_default() {
+            println!("cargo::warning=The current Rust version may cause issues, try using: \"nightly-{}-{}-{}\"", TOOLCHAIN_MAX.0, TOOLCHAIN_MAX.1, TOOLCHAIN_MAX.2);
+        }
+    }
+}
+
+/// Attempt to get the current toolchain version
+fn toolchain_version() -> Option<String> {
+    // Use the `RUSTUP_TOOLCHAIN` environment variable
+    if let Ok(toolchain) = env::var("RUSTUP_TOOLCHAIN") {
+        return Some(toolchain);
+    }
+
+    // Fallback to running `rustc -V`
+    let rustc_path = env::var("RUSTC")
+        .or_else(|_| env::var("CARGO_BUILD_RUSTC"))
+        .unwrap_or(String::from("rustc"));
+
+    let rustc_command = Command::new(&rustc_path).arg("-V").output().unwrap();
+    if rustc_command.status.success() {
+        String::from_utf8(rustc_command.stdout).ok()
+    } else {
+        None
+    }
+}
+
+
+/// Attempt to parse the version of the toolchain,
+/// returning `Some(true)` if the toolchain should be fine.
+fn recommended_toolchain(toolchain: &str) -> Option<bool> {
+    let mut split = toolchain.split('-');
+    while split.next() != Some("nightly") {}
+
+    let year = split.next()?.parse().ok()?;
+    let month = split.next()?.parse().ok()?;
+    let day = split.next()?.parse().ok()?;
+
+    Some((year, month, day) <= TOOLCHAIN_MAX)
+}