refactor(dynamic): introduce build pools for Python, C, C++, Go, Ruby, PHP, and Node.js with shared caching and warming improvements; enhance test coverage with micro-benchmarks

tests/dynamic_cpp_build_pool.rs

@@ -0,0 +1,92 @@
+//! Phase 23 / Track O.1 micro-benchmark for the C++ build pool.
+//!
+//! Asserts the hot-build P50 (a `ccache`-fronted recompile, or a bare trivial
+//! `c++` when ccache is absent) stays ≤ 1s, the compiled-language budget.
+//! Skips when `c++` is not runnable.
+
+#![cfg(feature = "dynamic")]
+
+use std::path::Path;
+use std::sync::{Mutex, MutexGuard};
+use std::time::{Duration, Instant};
+
+use nyx_scanner::dynamic::build_pool::BuildPool;
+use nyx_scanner::dynamic::build_pool::cpp::CppPool;
+
+static ENV_LOCK: Mutex<()> = Mutex::new(());
+
+struct PoolDirGuard {
+    _lock: MutexGuard<'static, ()>,
+    prior: Option<String>,
+    _dir: tempfile::TempDir,
+}
+
+impl PoolDirGuard {
+    fn isolated() -> Self {
+        let lock = ENV_LOCK.lock().unwrap_or_else(|p| p.into_inner());
+        let dir = tempfile::TempDir::new().unwrap();
+        let prior = std::env::var("NYX_BUILD_POOL_DIR").ok();
+        unsafe { std::env::set_var("NYX_BUILD_POOL_DIR", dir.path()) };
+        Self {
+            _lock: lock,
+            prior,
+            _dir: dir,
+        }
+    }
+}
+
+impl Drop for PoolDirGuard {
+    fn drop(&mut self) {
+        match self.prior.take() {
+            Some(v) => unsafe { std::env::set_var("NYX_BUILD_POOL_DIR", v) },
+            None => unsafe { std::env::remove_var("NYX_BUILD_POOL_DIR") },
+        }
+    }
+}
+
+fn median(mut ds: Vec<Duration>) -> Duration {
+    ds.sort();
+    ds[ds.len() / 2]
+}
+
+fn write_source(workdir: &Path) {
+    std::fs::write(workdir.join("main.cpp"), "int main() { return 0; }\n").unwrap();
+}
+
+#[test]
+#[ignore = "real-toolchain perf bench: spawns `c++`. Opt-in so the default suite stays hermetic + fast. Run: cargo nextest run --features dynamic --run-ignored ignored-only -E 'binary(~build_pool) | binary(~compile_pool)'"]
+fn hot_rebuild_p50_under_one_second() {
+    let _guard = PoolDirGuard::isolated();
+    let pool = match CppPool::try_new() {
+        Ok(p) => p,
+        Err(e) => {
+            eprintln!("skipping cpp build-pool bench: {e}");
+            return;
+        }
+    };
+
+    let work = tempfile::TempDir::new().unwrap();
+    write_source(work.path());
+    let dest = work.path().join("nyx_harness_out");
+    let args = [dest.to_string_lossy().into_owned()];
+
+    let cold = pool.compile_batch(work.path(), &args);
+    assert!(cold.success, "cold build must succeed: {}", cold.stderr);
+    assert!(dest.exists(), "cold build must emit the binary");
+
+    let mut hot = Vec::new();
+    for _ in 0..5 {
+        let _ = std::fs::remove_file(&dest);
+        let start = Instant::now();
+        let r = pool.compile_batch(work.path(), &args);
+        hot.push(start.elapsed());
+        assert!(r.success, "hot build must succeed: {}", r.stderr);
+    }
+
+    let p50 = median(hot);
+    eprintln!("cpp build-pool hot P50: {p50:?}");
+    assert!(
+        p50 <= Duration::from_secs(1),
+        "cpp hot-build P50 {p50:?} exceeds the 1s compiled budget",
+    );
+}