Add a native _zoneinfo module (#8915)

* Add a native _zoneinfo module

ZoneInfo reads TZif tuples from zoneinfo._common.load_data. The stdlib
module implements utcoffset, dst, tzname, fromutc, and the zone cache.
whats_left compares that class. Cache tests no longer expect failure.

Assisted-by: Grok:grok-4.7

* Fix ZoneInfo layout and keep its cache on the module

utcoffset, dst, and tzname take the object. Zone data is boxed so the
payload lines up with tzinfo on 32-bit. The strong, weak, and timedelta
caches live on each interpreter's _zoneinfo module.

Assisted-by: Grok:grok-4.7

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -1609,7 +1609,6 @@ class ZoneInfoCacheTest(TzPathUserMixin, ZoneInfoTestBase):
 class CZoneInfoCacheTest(ZoneInfoCacheTest):
     module = c_zoneinfo
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: RuntimeError not raised
     def test_inconsistent_weak_cache_get(self):
         class Cache:
             def get(self, key, default=None):
@@ -1628,7 +1627,6 @@ class CZoneInfoCacheTest(ZoneInfoCacheTest):
             "Unexpected instance of int in ZI weak cache for key 'America/Los_Angeles'"
         )
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: AttributeError not raised
     def test_deleted_weak_cache(self):
         class ZI(self.klass):
             pass
@@ -1641,7 +1639,6 @@ class CZoneInfoCacheTest(ZoneInfoCacheTest):
         with self.assertRaises(AttributeError):
             ZI.clear_cache()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AttributeError: 'int' object has no attribute '_from_cache'
     def test_inconsistent_weak_cache_setdefault(self):
         class Cache:
             def get(self, key, default=None):
@@ -2092,7 +2089,6 @@ class ExtensionBuiltTest(unittest.TestCase):
     rely on these tests as an indication of stable properties of these classes.
     """
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; AssertionError: type object 'ZoneInfo' has unexpected attribute '_weak_cache'
     def test_cache_location(self):
         # The pure Python version stores caches on attributes, but the C
         # extension stores them in C globals (at least for now)

crates/stdlib/src/_datetime.rs

@@ -5,7 +5,7 @@
 // cspell:ignore ymd ordinal isocalendar ISO fromisoformat
 // cspell:ignore dnum zreplacement colonzreplacement zname freplacement somezreplacement
 // cspell:ignore tzoffset tzmicrosecond tzsign dtstr nogo dtobj tzusec timet
-pub(crate) use _datetime::module_def;
+pub(crate) use _datetime::{PyTzInfo, datetime_type, module_def, timedelta_from_seconds};
 
 #[pymodule]
 mod _datetime {
@@ -940,10 +940,18 @@ mod _datetime {
         PyDate::static_type()
     }
 
-    fn datetime_type() -> &'static Py<PyType> {
+    pub(crate) fn datetime_type() -> &'static Py<PyType> {
         PyDateTime::static_type()
     }
 
+    pub(crate) fn timedelta_from_seconds(
+        seconds: i64,
+        vm: &VirtualMachine,
+    ) -> PyResult<PyObjectRef> {
+        let delta = PyDelta::new_ex(0, seconds, 0, true, vm)?;
+        Ok(delta.into_ref(&vm.ctx).into())
+    }
+
     fn time_type() -> &'static Py<PyType> {
         PyTime::static_type()
     }
@@ -2331,7 +2339,7 @@ mod _datetime {
     #[pyattr]
     #[pyclass(module = "datetime", name = "tzinfo")]
     #[derive(Debug, Default, PyPayload)]
-    pub(super) struct PyTzInfo {}
+    pub(crate) struct PyTzInfo {}
 
     impl Constructor for PyTzInfo {
         type Args = FuncArgs;

crates/stdlib/src/lib.rs

@@ -57,6 +57,7 @@ mod mmap;
 mod _datetime;
 mod _heapq;
 mod _queue;
+mod _zoneinfo;
 mod pickle;
 mod pyexpat;
 mod pystruct;
@@ -259,6 +260,7 @@ pub fn stdlib_module_defs(ctx: &Context) -> Vec<&'static builtins::PyModuleDef>
         pyexpat::module_def(ctx),
         pystruct::module_def(ctx),
         _datetime::module_def(ctx),
+        _zoneinfo::module_def(ctx),
         _heapq::module_def(ctx),
         _queue::module_def(ctx),
         random::module_def(ctx),

extra_tests/snippets/stdlib_zoneinfo_cache.py

@@ -0,0 +1,37 @@
+import tempfile
+from pathlib import Path
+from zoneinfo import ZoneInfo, reset_tzpath
+
+import _interpreters
+
+# Fixed-offset UTC TZif, so the cache check does not need system zone data.
+UTC = b"TZif2\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00UTC\x00TZif2\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00UTC\x00\nUTC0\n"
+
+with tempfile.TemporaryDirectory() as directory:
+    Path(directory, "UTC").write_bytes(UTC)
+    reset_tzpath([directory])
+    main = ZoneInfo("UTC")
+    assert main is ZoneInfo("UTC")
+
+    interp = _interpreters.create()
+    try:
+        result = _interpreters.run_string(
+            interp,
+            """
+from zoneinfo import ZoneInfo, reset_tzpath
+reset_tzpath([tzpath])
+first = ZoneInfo("UTC")
+second = ZoneInfo("UTC")
+assert first is second
+assert id(first) != main_id
+ZoneInfo.clear_cache()
+""",
+            {"tzpath": directory, "main_id": id(main)},
+        )
+    finally:
+        _interpreters.destroy(interp)
+
+    if result is not None:
+        detail = getattr(result, "formatted", None) or repr(result)
+        raise AssertionError(detail)
+    assert main is ZoneInfo("UTC")

scripts/whats_left.py

@@ -414,20 +414,6 @@ def _pure_decimal_baseline(wrapper):
     return result
 
 
-def _use_pure_zoneinfo(dir_result):
-    """Replace the accelerated ZoneInfo with the pure-Python class."""
-    import zoneinfo._zoneinfo as pure_zoneinfo
-
-    cls = pure_zoneinfo.ZoneInfo
-    name = cls.__name__
-    for key in list(dir_result):
-        if key == name or key.startswith(f"{name}."):
-            del dir_result[key]
-    dir_result[name] = extra_info(cls)
-    for attr, info in own_attrs(cls):
-        dir_result[f"{name}.{attr}"] = info
-
-
 def gen_modules():
     # check name because modules listed have side effects on import,
     # e.g. printing something or opening a webpage
@@ -465,8 +451,6 @@ def gen_modules():
             ):
                 for attr, info in own_attrs(item):
                     dir_result[f"{item_name}.{attr}"] = info
-        if mod_name == "zoneinfo":
-            _use_pure_zoneinfo(dir_result)
         modules[mod_name] = dir_result
     return modules