crates/vm/src/stdlib/io.rs (1)

23-44: Confirm libc::strerror semantics on Windows targets; consider centralizing helper

• libc::strerror’s thread-safety and returned “Unknown error” text can differ by CRT/toolchain/locale; please confirm this behaves as intended on the Windows targets RustPython supports (e.g., MSVC/UCRT vs MinGW) and that the "Unknown error" guard is robust enough.
• There’s already a strerror(e: i32) -> String helper in crates/vm/src/stdlib/os.rs:1542-1546 (per provided snippet); consider reusing/relocating a shared helper to avoid duplicating FFI + string handling logic.

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Review profile: CHILL

Plan: Pro

Learnt from: youknowone
Repo: RustPython/RustPython PR: 6358
File: crates/vm/src/exception_group.rs:173-185
Timestamp: 2025-12-09T08:46:58.660Z
Learning: In crates/vm/src/exception_group.rs, the derive() method intentionally always creates a BaseExceptionGroup instance rather than preserving the original exception class type. This is a deliberate design decision that differs from CPython's behavior.

crates/vm/src/stdlib/io.rs (2)

23-41: Consider extracting strerror logic to a shared helper.

The Windows block correctly handles POSIX errno translation with appropriate bounds checking and fallback logic. However, libc::strerror is not thread-safe—it returns a pointer to a static buffer that can be overwritten by concurrent calls. This matches the existing pattern in os.rs (lines 1542-1546), so it's consistent with the codebase.

Consider consolidating the strerror logic with the existing strerror helper in crates/vm/src/stdlib/os.rs to reduce duplication and centralize any future thread-safety improvements.

---

42-52: Unix strerror logic duplicates existing helper in os.rs.

This block is nearly identical to the strerror function at crates/vm/src/stdlib/os.rs:1542-1546. Consider reusing that function to avoid duplication:

 #[cfg(unix)]
 let msg = {
-    let ptr = unsafe { libc::strerror(errno) };
-    if !ptr.is_null() {
-        unsafe { std::ffi::CStr::from_ptr(ptr) }
-            .to_string_lossy()
-            .into_owned()
-    } else {
-        self.to_string()
-    }
+    // Reuse existing strerror helper from os module
+    crate::stdlib::os::strerror(errno)
 };

Note: This requires making the strerror function in os.rs public or moving it to a shared location.

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

Learnt from: youknowone
Repo: RustPython/RustPython PR: 6358
File: crates/vm/src/exception_group.rs:173-185
Timestamp: 2025-12-09T08:46:58.660Z
Learning: In crates/vm/src/exception_group.rs, the derive() method intentionally always creates a BaseExceptionGroup instance rather than preserving the original exception class type. This is a deliberate design decision that differs from CPython's behavior.