Walkthrough

Replaced a mutex-based field with an atomic pointer: PyCode.source_path now uses AtomicPtr<PyStrInterned>. Constructors and accessors were updated to store/load raw pointers with Ordering::Relaxed, relying on interned strings never being deallocated.

Changes

Sequence Diagram(s)

(omitted — changes are localized and do not introduce multi-component control flow requiring a sequence diagram)

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• Replace unsafe pointer cast with PyMutex in PyCode #7055 — Introduced a PyMutex-wrapped source_path for PyCode; this PR directly replaces that mutex-based approach with an AtomicPtr.

Poem

🐰 I swapped the lock for atomic cheer,
A pointer hops, no crowding near.
Relaxed it dances, light and spry,
Interned strings watch from on high. ✨

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

• 📝 Generate docstrings

crates/vm/src/builtins/code.rs (1)

349-359: Ordering::Relaxed is sufficient here, and the unsafe is sound.

Since the pointed-to PyStrInterned is immutable and 'static (interned strings are never deallocated), there's no dependent data requiring acquire/release synchronization. The only invariant is atomicity of the pointer swap, which Relaxed provides.

One minor observation: there's no doc-comment on set_source_path explaining why this is safe to call concurrently (i.e., the 'static + immutable invariant). Consider adding a brief // SAFETY: comment matching the one on source_path().

Suggested safety comment

     pub fn set_source_path(&self, new: &'static PyStrInterned) {
+        // SAFETY: interned strings are never deallocated, so the pointer remains valid
         self.source_path.store(
             new as *const PyStrInterned as *mut PyStrInterned,
             Ordering::Relaxed,
         );
     }

• X
• Mastodon
• Reddit
• LinkedIn