feat(sys): add sys.is_finalizing() (RustPython#3776)

Author: isac322

Lib/test/test_sys.py

@@ -892,7 +892,7 @@ def test_getallocatedblocks(self):
         c = sys.getallocatedblocks()
         self.assertIn(c, range(b - 50, b + 50))
 
-    # TODO: RUSTPYTHON, AttributeError: module 'sys' has no attribute 'is_finalizing'
+    # TODO: RUSTPYTHON, AtExit.__del__ is not invoked because module destruction is missing.
     @unittest.expectedFailure
     def test_is_finalizing(self):
         self.assertIs(sys.is_finalizing(), False)

vm/src/stdlib/sys.rs

@@ -19,6 +19,7 @@ mod sys {
         AsObject, PyObjectRef, PyRef, PyRefExact, PyResult,
     };
     use num_traits::ToPrimitive;
+    use std::sync::atomic::Ordering;
     use std::{env, mem, path};
 
     // not the same as CPython (e.g. rust's x86_x64-unknown-linux-gnu is just x86_64-linux-gnu)
@@ -521,6 +522,11 @@ mod sys {
         PyIntInfo::INFO.into_struct_sequence(vm)
     }
 
+    #[pyfunction]
+    fn is_finalizing(vm: &VirtualMachine) -> bool {
+        vm.state.finalizing.load(Ordering::Acquire)
+    }
+
     #[pyfunction]
     fn setprofile(profilefunc: PyObjectRef, vm: &VirtualMachine) {
         vm.profile_func.replace(profilefunc);

vm/src/vm/interpreter.rs

@@ -3,6 +3,7 @@ use crate::{
     stdlib::{atexit, sys},
     PyResult,
 };
+use std::sync::atomic::Ordering;
 
 /// The general interface for the VM
 ///
@@ -74,6 +75,8 @@ impl Interpreter {
 
             atexit::_run_exitfuncs(vm);
 
+            vm.state.finalizing.store(true, Ordering::Release);
+
             flush_std(vm);
 
             exit_code

vm/src/vm/mod.rs

@@ -34,6 +34,7 @@ use crate::{
     signal, stdlib, AsObject, PyObject, PyObjectRef, PyPayload, PyRef, PyResult,
 };
 use crossbeam_utils::atomic::AtomicCell;
+use std::sync::atomic::AtomicBool;
 use std::{
     borrow::Cow,
     cell::{Cell, Ref, RefCell},
@@ -86,6 +87,7 @@ pub struct PyGlobalState {
     pub hash_secret: HashSecret,
     pub atexit_funcs: PyMutex<Vec<(PyObjectRef, FuncArgs)>>,
     pub codec_registry: CodecsRegistry,
+    pub finalizing: AtomicBool,
 }
 
 pub fn process_hash_secret_seed() -> u32 {
@@ -158,6 +160,7 @@ impl VirtualMachine {
                 hash_secret,
                 atexit_funcs: PyMutex::default(),
                 codec_registry,
+                finalizing: AtomicBool::new(false),
             }),
             initialized: false,
             recursion_depth: Cell::new(0),