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gh-135443: Sometimes Fall Back to __main__.__dict__ For Globals #135491

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Merged
merged 11 commits into from
Jun 16, 2025
Merged

gh-135443: Sometimes Fall Back to __main__.__dict__ For Globals #135491

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54ea52b
Add tests.
ericsnowcurrently Jun 6, 2025
39afdac
Refactor before adding _PyEval_GetGlobalsFromRunningMain().
ericsnowcurrently Jun 13, 2025
3cfddbc
Fall back to __main__.__dict__ if running main.
ericsnowcurrently Jun 13, 2025
1d5b7bd
Fix the fallback.
ericsnowcurrently Jun 16, 2025
2f8caf0
Fix a typo.
ericsnowcurrently Jun 16, 2025
77fbd1f
Use a clearer variable name in a test.
ericsnowcurrently Jun 16, 2025
2bf3a4b
Fix type handling in _PyEval_EnsureBuiltins().
ericsnowcurrently Jun 16, 2025
69109c6
Add _PyEval_EnsureBuiltinsWithModule().
ericsnowcurrently Jun 16, 2025
44a39a5
more tests
ericsnowcurrently Jun 16, 2025
cbc4d3f
Set __globals__ to __main__.__dict__ for stateless funcs.
ericsnowcurrently Jun 16, 2025
c93f890
Move tests down.
ericsnowcurrently Jun 16, 2025
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7 changes: 7 additions & 0 deletions Include/internal/pycore_ceval.h
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Original file line number Diff line number Diff line change
Expand Up @@ -239,6 +239,13 @@ static inline void _Py_LeaveRecursiveCall(void) {

extern _PyInterpreterFrame* _PyEval_GetFrame(void);

extern PyObject * _PyEval_GetGlobalsFromRunningMain(PyThreadState *);
extern int _PyEval_EnsureBuiltins(
PyThreadState *,
PyObject *,
int usemod,
PyObject **p_builtins);

PyAPI_FUNC(PyObject *)_Py_MakeCoro(PyFunctionObject *func);

/* Handle signals, pending calls, GIL drop request
Expand Down
35 changes: 35 additions & 0 deletions Lib/test/test_interpreters/test_api.py
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Expand Up @@ -1414,6 +1414,41 @@ def test_call_invalid(self):
with self.assertRaises(interpreters.NotShareableError):
interp.call(func, op, 'eggs!')

def test_callable_requires_frame(self):
# There are various functions tha require a current frame.
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a typo in the comment.

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fixed

interp = interpreters.create()
for call, expected in [
((eval, '[1, 2, 3]'),
[1, 2, 3]),
((eval, 'sum([1, 2, 3])'),
6),
((exec, '...'),
None),
]:
with self.subTest(str(call)):
res = interp.call(*call)
self.assertEqual(res, expected)

notshareable = [
globals,
locals,
vars,
]
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@neonene neonene Jun 15, 2025 •
edited
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If "notshareable" here means that the result of the functions cannot be pickled, could NotShareableError differentiate the round-trip in the future? Also, interpreters.is_shareable() returns False for both globals and dir, which might be confusing at first.

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fixed

for func, expectedtype in {
globals: dict,
locals: dict,
vars: dict,
dir: list,
}.items():
with self.subTest(str(func)):
if func in notshareable:
with self.assertRaises(interpreters.NotShareableError):
interp.call(func)
else:
res = interp.call(func)
self.assertIsInstance(res, expectedtype)
self.assertIn('__builtins__', res)

def test_call_in_thread(self):
interp = interpreters.create()

Expand Down
18 changes: 16 additions & 2 deletions Objects/object.c
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Expand Up @@ -2083,9 +2083,23 @@ _dir_locals(void)
PyObject *names;
PyObject *locals;

locals = _PyEval_GetFrameLocals();
if (locals == NULL)
if (_PyEval_GetFrame() != NULL) {
locals = _PyEval_GetFrameLocals();
}
PyThreadState *tstate = _PyThreadState_GET();
locals = _PyEval_GetGlobalsFromRunningMain(tstate);
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@neonene neonene Jun 15, 2025 •
edited
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_PyEval_GetFrameLocals() returns a new reference (leak), which is overwritten by _PyEval_GetGlobalsFromRunningMain(). Thus the fallback mechanism looks to be missing.

The same goes for builtin_vars().

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fixed

if (locals == NULL) {
if (!_PyErr_Occurred(tstate)) {
locals = _PyEval_GetFrameLocals();
assert(_PyErr_Occurred(tstate));
}
}
else {
Py_INCREF(locals);
}
if (locals == NULL) {
return NULL;
}

names = PyMapping_Keys(locals);
Py_DECREF(locals);
Expand Down
161 changes: 113 additions & 48 deletions Python/bltinmodule.c
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Expand Up @@ -957,6 +957,7 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
PyObject *locals)
/*[clinic end generated code: output=0a0824aa70093116 input=7c7bce5299a89062]*/
{
PyThreadState *tstate = _PyThreadState_GET();
PyObject *result = NULL, *source_copy;
const char *str;

Expand All @@ -970,35 +971,46 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
: "globals must be a dict");
return NULL;
}
if (globals == Py_None) {

int fromframe = 0;
if (globals != Py_None) {
Py_INCREF(globals);
}
else if (_PyEval_GetFrame() != NULL) {
fromframe = 1;
globals = PyEval_GetGlobals();
if (locals == Py_None) {
locals = _PyEval_GetFrameLocals();
if (locals == NULL)
return NULL;
}
else {
Py_INCREF(locals);
}
assert(globals != NULL);
Py_INCREF(globals);
}
else if (locals == Py_None)
locals = Py_NewRef(globals);
else {
Py_INCREF(locals);
globals = _PyEval_GetGlobalsFromRunningMain(tstate);
if (globals == NULL) {
if (!_PyErr_Occurred(tstate)) {
PyErr_SetString(PyExc_TypeError,
"eval must be given globals and locals "
"when called without a frame");
}
return NULL;
}
Py_INCREF(globals);
}

if (globals == NULL || locals == NULL) {
PyErr_SetString(PyExc_TypeError,
"eval must be given globals and locals "
"when called without a frame");
goto error;
if (locals != Py_None) {
Py_INCREF(locals);
}

int r = PyDict_Contains(globals, &_Py_ID(__builtins__));
if (r == 0) {
r = PyDict_SetItem(globals, &_Py_ID(__builtins__), PyEval_GetBuiltins());
else if (fromframe) {
locals = _PyEval_GetFrameLocals();
if (locals == NULL) {
assert(PyErr_Occurred());
Py_DECREF(globals);
return NULL;
}
}
else {
locals = Py_NewRef(globals);
}
if (r < 0) {

if (_PyEval_EnsureBuiltins(tstate, globals, 0, NULL) < 0) {
goto error;
}

Expand Down Expand Up @@ -1039,6 +1051,7 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
}

error:
Py_XDECREF(globals);
Py_XDECREF(locals);
return result;
}
Expand Down Expand Up @@ -1069,29 +1082,44 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
PyObject *locals, PyObject *closure)
/*[clinic end generated code: output=7579eb4e7646743d input=25e989b6d87a3a21]*/
{
PyThreadState *tstate = _PyThreadState_GET();
PyObject *v;

if (globals == Py_None) {
int fromframe = 0;
if (globals != Py_None) {
Py_INCREF(globals);
}
else if (_PyEval_GetFrame() != NULL) {
fromframe = 1;
globals = PyEval_GetGlobals();
if (locals == Py_None) {
locals = _PyEval_GetFrameLocals();
if (locals == NULL)
return NULL;
}
else {
Py_INCREF(locals);
assert(globals != NULL);
Py_INCREF(globals);
}
else {
globals = _PyEval_GetGlobalsFromRunningMain(tstate);
if (globals == NULL) {
if (!_PyErr_Occurred(tstate)) {
PyErr_SetString(PyExc_SystemError,
"globals and locals cannot be NULL");
}
goto error;
}
if (!globals || !locals) {
PyErr_SetString(PyExc_SystemError,
"globals and locals cannot be NULL");
Py_INCREF(globals);
}

if (locals != Py_None) {
Py_INCREF(locals);
}
else if (fromframe) {
locals = _PyEval_GetFrameLocals();
if (locals == NULL) {
assert(PyErr_Occurred());
Py_DECREF(globals);
return NULL;
}
}
else if (locals == Py_None) {
locals = Py_NewRef(globals);
}
else {
Py_INCREF(locals);
locals = Py_NewRef(globals);
}

if (!PyDict_Check(globals)) {
Expand All @@ -1105,11 +1133,8 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
Py_TYPE(locals)->tp_name);
goto error;
}
int r = PyDict_Contains(globals, &_Py_ID(__builtins__));
if (r == 0) {
r = PyDict_SetItem(globals, &_Py_ID(__builtins__), PyEval_GetBuiltins());
}
if (r < 0) {

if (_PyEval_EnsureBuiltins(tstate, globals, 0, NULL) < 0) {
goto error;
}

Expand Down Expand Up @@ -1186,11 +1211,13 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
}
if (v == NULL)
goto error;
Py_DECREF(globals);
Py_DECREF(locals);
Py_DECREF(v);
Py_RETURN_NONE;

error:
Py_XDECREF(globals);
Py_XDECREF(locals);
return NULL;
}
Expand Down Expand Up @@ -1240,10 +1267,21 @@ static PyObject *
builtin_globals_impl(PyObject *module)
/*[clinic end generated code: output=e5dd1527067b94d2 input=9327576f92bb48ba]*/
{
PyObject *d;

d = PyEval_GetGlobals();
return Py_XNewRef(d);
PyObject *globals;
if (_PyEval_GetFrame() != NULL) {
globals = PyEval_GetGlobals();
assert(globals != NULL);
return Py_NewRef(globals);
}
PyThreadState *tstate = _PyThreadState_GET();
globals = _PyEval_GetGlobalsFromRunningMain(tstate);
if (globals == NULL) {
if (_PyErr_Occurred(tstate)) {
return NULL;
}
Py_RETURN_NONE;
}
return Py_NewRef(globals);
}


Expand Down Expand Up @@ -1887,7 +1925,21 @@ static PyObject *
builtin_locals_impl(PyObject *module)
/*[clinic end generated code: output=b46c94015ce11448 input=7874018d478d5c4b]*/
{
return _PyEval_GetFrameLocals();
PyObject *locals;
if (_PyEval_GetFrame() != NULL) {
locals = _PyEval_GetFrameLocals();
assert(locals != NULL || PyErr_Occurred());
return locals;
}
PyThreadState *tstate = _PyThreadState_GET();
locals = _PyEval_GetGlobalsFromRunningMain(tstate);
if (locals == NULL) {
if (_PyErr_Occurred(tstate)) {
return NULL;
}
Py_RETURN_NONE;
}
return Py_NewRef(locals);
}


Expand Down Expand Up @@ -2623,7 +2675,20 @@ builtin_vars(PyObject *self, PyObject *args)
if (!PyArg_UnpackTuple(args, "vars", 0, 1, &v))
return NULL;
if (v == NULL) {
d = _PyEval_GetFrameLocals();
if (_PyEval_GetFrame() != NULL) {
d = _PyEval_GetFrameLocals();
}
PyThreadState *tstate = _PyThreadState_GET();
d = _PyEval_GetGlobalsFromRunningMain(tstate);
if (d == NULL) {
if (!_PyErr_Occurred(tstate)) {
d = _PyEval_GetFrameLocals();
assert(_PyErr_Occurred(tstate));
}
}
else {
Py_INCREF(d);
}
}
else {
if (PyObject_GetOptionalAttr(v, &_Py_ID(__dict__), &d) == 0) {
Expand Down
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