Skip to content

GH-151619: Ensure non-module global/builtin namespaces are watched for lazy imports #151762

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
brandtbucher wants to merge 2 commits into
base: main
Choose a base branch
from
+86 −1
Open

GH-151619: Ensure non-module global/builtin namespaces are watched for lazy imports #151762

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a133975
Watch lazy import dicts during global specialization
brandtbucher Jun 19, 2026
72485bc
blurb add
brandtbucher Jun 19, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
75 changes: 75 additions & 0 deletions Lib/test/test_lazy_import/__init__.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -949,6 +949,81 @@ def f():
self.assertEqual(result.returncode, 0, f"stdout: {result.stdout}, stderr: {result.stderr}")
self.assertIn("OK", result.stdout)

def test_add_lazy_to_exec_globals_after_specialization(self):
code = textwrap.dedent("""
source = '''
import sys
import types

lazy from test.test_lazy_import.data import basic2

assert 'test.test_lazy_import.data.basic2' not in sys.modules

class C: pass
sneaky = C()
sneaky.x = 1

def f():
t = 0
for _ in range(5):
t += sneaky.x
return t

f()
globals()["sneaky"] = globals()["basic2"]
assert f() == 210
print("OK")
'''
ns = {"__name__": "lazy_exec_globals"}
exec(source, ns)
""")
result = subprocess.run(
[sys.executable, "-c", code],
capture_output=True,
text=True
)
self.assertEqual(result.returncode, 0, f"stdout: {result.stdout}, stderr: {result.stderr}")
self.assertIn("OK", result.stdout)

def test_add_lazy_to_exec_builtins_after_specialization(self):
code = textwrap.dedent("""
import builtins
source = '''
import sys
import types

lazy from test.test_lazy_import.data import basic2

assert 'test.test_lazy_import.data.basic2' not in sys.modules

class C: pass
sneaky = C()
sneaky.x = 1
__builtins__["sneaky"] = sneaky
del sneaky

def f():
t = 0
for _ in range(5):
t += sneaky.x
return t

f()
__builtins__["sneaky"] = globals()["basic2"]
assert f() == 210
print("OK")
'''
ns = {"__name__": "lazy_exec_builtins", "__builtins__": builtins.__dict__.copy()}
exec(source, ns)
""")
result = subprocess.run(
[sys.executable, "-c", code],
capture_output=True,
text=True
)
self.assertEqual(result.returncode, 0, f"stdout: {result.stdout}, stderr: {result.stderr}")
self.assertIn("OK", result.stdout)


@support.requires_subprocess()
class MultipleNameFromImportTests(LazyImportTestCase):
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-06-19-16-40-01.gh-issue-151619.35yyJW.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Fix an issue where using non-module global or builtin namespaces (such as
dictionaries passed to :func:`exec`) could cause cached global loads to
produce unresolved :ref:`lazy imports <lazy-imports>`.
9 changes: 8 additions & 1 deletion Python/specialize.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1386,6 +1386,7 @@ specialize_load_global_lock_held(
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
}
PyDict_Watch(MODULE_WATCHER_ID, globals);
#ifdef Py_GIL_DISABLED
maybe_enable_deferred_ref_count(value);
#endif
Expand All @@ -1403,11 +1404,15 @@ specialize_load_global_lock_held(
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_LOAD_GLOBAL_NON_STRING_OR_SPLIT);
goto fail;
}
index = _PyDictKeys_StringLookup(builtin_keys, name);
index = _PyDict_LookupIndexAndValue((PyDictObject *)builtins, name, &value);
if (index == DKIX_ERROR) {
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_EXPECTED_ERROR);
goto fail;
}
if (value != NULL && PyLazyImport_CheckExact(value)) {
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_ATTR_MODULE_LAZY_VALUE);
goto fail;
}
if (index != (uint16_t)index) {
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
Expand All @@ -1422,6 +1427,7 @@ specialize_load_global_lock_held(
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
}
PyDict_Watch(MODULE_WATCHER_ID, globals);
uint32_t builtins_version = _PyDict_GetKeysVersionForCurrentState(
interp, (PyDictObject*) builtins);
if (builtins_version == 0) {
Expand All @@ -1432,6 +1438,7 @@ specialize_load_global_lock_held(
SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
}
PyDict_Watch(MODULE_WATCHER_ID, builtins);
cache->index = (uint16_t)index;
cache->module_keys_version = (uint16_t)globals_version;
cache->builtin_keys_version = (uint16_t)builtins_version;
Expand Down
Loading