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Carl Meyerfacebook-github-bot
Carl Meyer
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backport 3.12 func watchers
Summary: Backport function watchers from upstream 3.12 (cf python/cpython#98175, although I backported from latest 3.12 branch, which has had a few modifications.) This diff doesn't use the new API yet; I'll do that in a separate stacked diff. Reviewed By: DinoV Differential Revision: D46993187 fbshipit-source-id: 35f3a0f86f6f0e2764205d4c865e1fb5efb69314
1 parent 21da38a commit 9fee3f9

6 files changed

Lines changed: 508 additions & 1 deletion

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‎Cinder/module/known-core-python-exported-symbols‎

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@@ -858,7 +858,9 @@ PyFrozenSet_New
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PyFrozenSet_Type
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_Py_fstat
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_Py_fstat_noraise
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PyFunction_AddWatcher
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_PyFunction_CallStatic
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PyFunction_ClearWatcher
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PyFunction_GetAnnotations
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PyFunction_GetClosure
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PyFunction_GetCode

‎Include/funcobject.h‎

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@@ -54,7 +54,7 @@ typedef struct {
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/* Temporarily disabling BOLT on this function as we end up with a
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* comparison to the unoptimized function when referred to from a
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* comparison to the unoptimized function when referred to from a
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* function which isn't being BOLTed */
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#define PyEntry_LazyInit PyEntry_LazyInit_dont_bolt
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@@ -119,6 +119,57 @@ PyAPI_DATA(PyTypeObject) PyStaticMethod_Type;
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PyAPI_FUNC(PyObject *) PyClassMethod_New(PyObject *);
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PyAPI_FUNC(PyObject *) PyStaticMethod_New(PyObject *);
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#define FUNC_MAX_WATCHERS 8
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#define PY_FOREACH_FUNC_EVENT(V) \
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V(CREATE) \
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V(DESTROY) \
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V(MODIFY_CODE) \
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V(MODIFY_DEFAULTS) \
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V(MODIFY_KWDEFAULTS)
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typedef enum {
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#define PY_DEF_EVENT(EVENT) PyFunction_EVENT_##EVENT,
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PY_FOREACH_FUNC_EVENT(PY_DEF_EVENT)
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#undef PY_DEF_EVENT
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} PyFunction_WatchEvent;
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/*
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* A callback that is invoked for different events in a function's lifecycle.
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*
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* The callback is invoked with a borrowed reference to func, after it is
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* created and before it is modified or destroyed. The callback should not
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* modify func.
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*
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* When a function's code object, defaults, or kwdefaults are modified the
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* callback will be invoked with the respective event and new_value will
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* contain a borrowed reference to the new value that is about to be stored in
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* the function. Otherwise the third argument is NULL.
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*
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* If the callback returns with an exception set, it must return -1. Otherwise
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* it should return 0.
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*/
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typedef int (*PyFunction_WatchCallback)(
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PyFunction_WatchEvent event,
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PyFunctionObject *func,
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PyObject *new_value);
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/*
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* Register a per-interpreter callback that will be invoked for function lifecycle
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* events.
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*
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* Returns a handle that may be passed to PyFunction_ClearWatcher on success,
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* or -1 and sets an error if no more handles are available.
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*/
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PyAPI_FUNC(int) PyFunction_AddWatcher(PyFunction_WatchCallback callback);
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/*
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* Clear the watcher associated with the watcher_id handle.
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*
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* Returns 0 on success or -1 if no watcher exists for the supplied id.
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*/
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PyAPI_FUNC(int) PyFunction_ClearWatcher(int watcher_id);
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#ifdef __cplusplus
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}
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#endif

‎Include/internal/pycore_interp.h‎

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@@ -278,6 +278,9 @@ struct _is {
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_PyFrameEvalFunction eval_frame;
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PyDict_WatchCallback dict_watchers[DICT_MAX_WATCHERS];
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PyFunction_WatchCallback func_watchers[FUNC_MAX_WATCHERS];
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// One bit is set for each non-NULL entry in func_watchers
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uint8_t active_func_watchers;
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Py_ssize_t co_extra_user_count;
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freefunc co_extra_freefuncs[MAX_CO_EXTRA_USERS];

‎Lib/test/test_capi.py‎

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Original file line numberDiff line numberDiff line change
@@ -1221,5 +1221,116 @@ def test_clear_unassigned_watcher_id(self):
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self.clear_watcher(1)
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class TestFuncWatchers(unittest.TestCase):
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@contextmanager
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def add_watcher(self, func):
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wid = _testcapi.add_func_watcher(func)
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try:
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yield
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finally:
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_testcapi.clear_func_watcher(wid)
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def test_func_events_dispatched(self):
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events = []
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def watcher(*args):
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events.append(args)
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with self.add_watcher(watcher):
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def myfunc():
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pass
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self.assertIn((_testcapi.PYFUNC_EVENT_CREATE, myfunc, None), events)
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myfunc_id = id(myfunc)
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new_code = self.test_func_events_dispatched.__code__
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myfunc.__code__ = new_code
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self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_CODE, myfunc, new_code), events)
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new_defaults = (123,)
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myfunc.__defaults__ = new_defaults
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self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_DEFAULTS, myfunc, new_defaults), events)
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1252+
new_defaults = (456,)
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_testcapi.set_func_defaults_via_capi(myfunc, new_defaults)
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self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_DEFAULTS, myfunc, new_defaults), events)
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new_kwdefaults = {"self": 123}
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myfunc.__kwdefaults__ = new_kwdefaults
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self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_KWDEFAULTS, myfunc, new_kwdefaults), events)
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new_kwdefaults = {"self": 456}
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_testcapi.set_func_kwdefaults_via_capi(myfunc, new_kwdefaults)
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self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_KWDEFAULTS, myfunc, new_kwdefaults), events)
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# Clear events reference to func
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events = []
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del myfunc
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self.assertIn((_testcapi.PYFUNC_EVENT_DESTROY, myfunc_id, None), events)
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1269+
def test_multiple_watchers(self):
1270+
events0 = []
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def first_watcher(*args):
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events0.append(args)
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events1 = []
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def second_watcher(*args):
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events1.append(args)
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with self.add_watcher(first_watcher):
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with self.add_watcher(second_watcher):
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def myfunc():
1281+
pass
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event = (_testcapi.PYFUNC_EVENT_CREATE, myfunc, None)
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self.assertIn(event, events0)
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self.assertIn(event, events1)
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def test_watcher_raises_error(self):
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class MyError(Exception):
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pass
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def watcher(*args):
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raise MyError("testing 123")
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with self.add_watcher(watcher):
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with catch_unraisable_exception() as cm:
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def myfunc():
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pass
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self.assertEqual(
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cm.unraisable.object,
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f"PyFunction_EVENT_CREATE watcher callback for {myfunc!r}"
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)
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def test_dealloc_watcher_raises_error(self):
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class MyError(Exception):
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pass
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def watcher(*args):
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raise MyError("testing 123")
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def myfunc():
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pass
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1314+
with self.add_watcher(watcher):
1315+
with catch_unraisable_exception() as cm:
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del myfunc
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self.assertIsInstance(cm.unraisable.exc_value, MyError)
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1320+
def test_clear_out_of_range_watcher_id(self):
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with self.assertRaisesRegex(ValueError, r"invalid func watcher ID -1"):
1322+
_testcapi.clear_func_watcher(-1)
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with self.assertRaisesRegex(ValueError, r"invalid func watcher ID 8"):
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_testcapi.clear_func_watcher(8) # FUNC_MAX_WATCHERS = 8
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1326+
def test_clear_unassigned_watcher_id(self):
1327+
with self.assertRaisesRegex(ValueError, r"no func watcher set for ID 1"):
1328+
_testcapi.clear_func_watcher(1)
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1330+
def test_allocate_too_many_watchers(self):
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with self.assertRaisesRegex(RuntimeError, r"no more func watcher IDs"):
1332+
_testcapi.allocate_too_many_func_watchers()
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12241335
if __name__ == "__main__":
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unittest.main()

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