PVF: Add worker check during tests and benches (#1771)

polkadot/node/core/pvf/src/testing.rs

@@ -15,13 +15,20 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Various things for testing other crates.
-//!
-//! N.B. This is not guarded with some feature flag. Overexposing items here may affect the final
-//!      artifact even for production builds.
 
-pub use crate::worker_intf::{spawn_with_program_path, SpawnErr};
+pub use crate::{
+	host::{EXECUTE_BINARY_NAME, PREPARE_BINARY_NAME},
+	worker_intf::{spawn_with_program_path, SpawnErr},
+};
 
+use crate::get_worker_version;
+use is_executable::IsExecutable;
+use polkadot_node_primitives::NODE_VERSION;
 use polkadot_primitives::ExecutorParams;
+use std::{
+	path::PathBuf,
+	sync::{Mutex, OnceLock},
+};
 
 /// A function that emulates the stitches together behaviors of the preparation and the execution
 /// worker in a single synchronous function.
@@ -47,3 +54,46 @@ pub fn validate_candidate(
 
 	Ok(result)
 }
+
+/// Retrieves the worker paths, checks that they exist and does a version check.
+///
+/// NOTE: This should only be called in dev code (tests, benchmarks) as it relies on the relative
+/// paths of the built workers.
+pub fn get_and_check_worker_paths() -> (PathBuf, PathBuf) {
+	// Only needs to be called once for the current process.
+	static WORKER_PATHS: OnceLock<Mutex<(PathBuf, PathBuf)>> = OnceLock::new();
+	let mutex = WORKER_PATHS.get_or_init(|| {
+		let mut workers_path = std::env::current_exe().unwrap();
+		workers_path.pop();
+		workers_path.pop();
+		let mut prepare_worker_path = workers_path.clone();
+		prepare_worker_path.push(PREPARE_BINARY_NAME);
+		let mut execute_worker_path = workers_path.clone();
+		execute_worker_path.push(EXECUTE_BINARY_NAME);
+
+		// Check that the workers are valid.
+		if !prepare_worker_path.is_executable() || !execute_worker_path.is_executable() {
+			panic!("ERROR: Workers do not exist or are not executable. Workers directory: {:?}", workers_path);
+		}
+
+		let worker_version =
+			get_worker_version(&prepare_worker_path).expect("checked for worker existence");
+		if worker_version != NODE_VERSION {
+			panic!("ERROR: Prepare worker version {worker_version} does not match node version {NODE_VERSION}; worker path: {prepare_worker_path:?}");
+		}
+		let worker_version =
+			get_worker_version(&execute_worker_path).expect("checked for worker existence");
+		if worker_version != NODE_VERSION {
+			panic!("ERROR: Execute worker version {worker_version} does not match node version {NODE_VERSION}; worker path: {execute_worker_path:?}");
+		}
+
+		// We don't want to check against the commit hash because we'd have to always rebuild
+		// the calling crate on every commit.
+		eprintln!("WARNING: Workers match the node version, but may have changed in recent commits. Please rebuild them if anything funny happens. Workers path: {workers_path:?}");
+
+		Mutex::new((prepare_worker_path, execute_worker_path))
+	});
+
+	let guard = mutex.lock().unwrap();
+	(guard.0.clone(), guard.1.clone())
+}