Rust: Force stable toolchain

Author: paldepind

rust/extractor/src/config.rs

@@ -23,6 +23,8 @@ use std::collections::HashSet;
 use std::fmt::Debug;
 use std::ops::Not;
 use std::path::{Path, PathBuf};
+use std::process::Command;
+use tracing::{info, warn};
 
 #[derive(Debug, PartialEq, Eq, Default, Serialize, Deserialize, Clone, Copy, clap::ValueEnum)]
 #[serde(rename_all = "lowercase")]
@@ -140,9 +142,41 @@ impl Config {
             );
         }
         extra_env.extend(self.cargo_extra_env.clone());
+        // Always use the latest stable toolchain, irrespective of any toolchain
+        // file in the project being extracted.
+        extra_env.insert("RUSTUP_TOOLCHAIN".to_owned(), Some("stable".to_owned()));
         extra_env
     }
 
+    pub(crate) fn apply_extra_env(&self, command: &mut Command) {
+        for (key, value) in self.get_extra_env() {
+            match value {
+                Some(value) => command.env(key, value),
+                None => command.env_remove(key),
+            };
+        }
+    }
+
+    pub(crate) fn log_effective_toolchain(&self, dir: &AbsPath) {
+        let mut command = Command::new("rustc");
+        command
+            .current_dir(dir.as_str())
+            .args(["--version", "--verbose"]);
+        self.apply_extra_env(&mut command);
+
+        match command.output() {
+            Ok(output) if output.status.success() => info!(
+                "effective Rust toolchain:\n{}",
+                String::from_utf8_lossy(&output.stdout).trim()
+            ),
+            Ok(output) => warn!(
+                "unable to determine effective Rust toolchain: {}",
+                String::from_utf8_lossy(&output.stderr).trim()
+            ),
+            Err(error) => warn!("unable to determine effective Rust toolchain: {error}"),
+        }
+    }
+
     fn sysroot(&self, dir: &AbsPath) -> Sysroot {
         let sysroot_input = self.sysroot.as_ref().map(|p| join_path_buf(dir, p));
         let sysroot_src_input = self.sysroot_src.as_ref().map(|p| join_path_buf(dir, p));

rust/extractor/src/main.rs

@@ -269,6 +269,7 @@ fn main() -> anyhow::Result<()> {
         );
     }
     let cwd = cwd()?;
+    cfg.log_effective_toolchain(&cwd);
     let (cargo_config, load_cargo_config) = cfg.to_cargo_config(&cwd);
     let library_mode = if cfg.extract_dependencies_as_source {
         SourceKind::Source

rust/extractor/src/qltest.rs

@@ -94,12 +94,7 @@ fn cargo_check(config: &Config) -> anyhow::Result<()> {
     let mut command = Command::new("cargo");
     command.env("CARGO_TARGET_DIR", config.cargo_target_dir());
     // Pass the extra environment variables to the initial `cargo check`.
-    for (key, value) in config.get_extra_env() {
-        match value {
-            Some(value) => command.env(key, value),
-            None => command.env_remove(key),
-        };
-    }
+    config.apply_extra_env(&mut command);
     let status = command
         .arg("check")
         .arg("-q")