Fix #2725: Add temporary shims for old cuda_bindings._test_helpers

.github/RELEASE-core.md

@@ -87,6 +87,13 @@ This must happen *before* the release tag is cut. Removals are breaking
 changes, so they are only permitted at a major-version boundary per the
 [support policy](https://nvidia.github.io/cuda-python/cuda-core/latest/support.html).
 
+There may also be deprecations in `cuda-bindings` tied to a particular `cuda-core` release.
+Find those this way:
+
+```console
+$ grep -rn 'deprecated:: cuda-core' cuda_bindings/cuda
+```
+
 ---
 
 ## Finalize the doc update, including release notes

cuda_bindings/cuda/bindings/_test_helpers/__init__.py

@@ -0,0 +1,84 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Deprecated shim package.
+
+These helpers moved to ``cuda_python_test_helpers`` in #2384 (2026-08-04).
+This package is kept for one cuda-core release cycle so that already-released
+cuda-core test trees (<=1.1.x), which still import from here, keep working
+against newer cuda-bindings wheels. See #2725.
+
+The idea here is to import the current cuda_python_test_helpers that cuda_bindings
+expects, even if the real cuda_python_test_helpers name is already claimed by an older,
+incompatible copy.
+
+.. deprecated:: cuda-core-1.2
+    Remove this entire subpackage once cuda-core >= 1.2 is the oldest supported
+    release.
+"""
+
+import importlib
+import importlib.util
+import pathlib
+import sys
+
+# Private alias under which a modern (post-#2384) cuda_python_test_helpers
+# source checkout is loaded, when the real `cuda_python_test_helpers` name is
+# already claimed by an older, incompatible copy. See _import_current below.
+_CURRENT_ALIAS = "_cuda_bindings_test_helpers_current"
+
+
+def _find_current_test_helpers_package():
+    """Locate and load cuda_python_test_helpers source checkout under a private
+    alias name, bypassing sys.modules entirely.
+    """
+    if _CURRENT_ALIAS in sys.modules:
+        return sys.modules[_CURRENT_ALIAS]
+
+    candidates = [*pathlib.Path(__file__).parents, pathlib.Path.cwd(), *pathlib.Path.cwd().parents]
+    seen: set[pathlib.Path] = set()
+    for candidate in candidates:
+        if candidate in seen:
+            continue
+        seen.add(candidate)
+        pkg_dir = candidate / "cuda_python_test_helpers" / "cuda_python_test_helpers"
+        init_file = pkg_dir / "__init__.py"
+        if init_file.is_file() and (pkg_dir / "arch_check.py").is_file():
+            spec = importlib.util.spec_from_file_location(
+                _CURRENT_ALIAS, init_file, submodule_search_locations=[str(pkg_dir)]
+            )
+            if spec is None or spec.loader is None:
+                continue
+            module = importlib.util.module_from_spec(spec)
+            sys.modules[_CURRENT_ALIAS] = module
+            spec.loader.exec_module(module)
+            return module
+
+    return None
+
+
+def _import_current(submodule_name: str):
+    """Import cuda_python_test_helpers.<submodule_name>.
+
+    Prefers whatever is already importable under the real
+    ``cuda_python_test_helpers`` name. Falls back to a modern copy loaded under
+    a private alias if the real name resolves to an older, incompatible copy --
+    e.g. released cuda-core <= 1.1.1 (tagged 2026-07-29, six days before #2384
+    landed) ships its own ``tests/conftest.py`` that puts a pre-#2384
+    ``cuda_python_test_helpers`` (predating arch_check.py / mempool.py /
+    pep723.py living there at all) on sys.path and caches it in sys.modules
+    under the real name before this shim ever runs.
+    """
+    try:
+        return importlib.import_module(f"cuda_python_test_helpers.{submodule_name}")
+    except ImportError:
+        pass
+
+    module = _find_current_test_helpers_package()
+    if module is None:
+        raise ModuleNotFoundError(
+            f"cuda_python_test_helpers.{submodule_name} is required by cuda.bindings._test_helpers "
+            "but is not installed, and no source checkout containing it was found near this file "
+            "or the current working directory."
+        )
+    return importlib.import_module(f"{module.__name__}.{submodule_name}")

cuda_bindings/cuda/bindings/_test_helpers/arch_check.py

@@ -0,0 +1,15 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Deprecated shim. Moved to cuda_python_test_helpers.arch_check in #2384 (2026-08-04).
+Kept for one release cycle so released cuda-core test trees keep importing.
+Remove after cuda-core >= 1.2 is the oldest supported release.
+"""
+
+from cuda.bindings._test_helpers import _import_current
+
+_arch_check = _import_current("arch_check")
+hardware_supports_nvml = _arch_check.hardware_supports_nvml
+unsupported_before = _arch_check.unsupported_before
+
+__all__ = ["hardware_supports_nvml", "unsupported_before"]

cuda_bindings/cuda/bindings/_test_helpers/mempool.py

@@ -0,0 +1,15 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Deprecated shim. Moved to cuda_python_test_helpers.mempool in #2384 (2026-08-04).
+Kept for one release cycle so released cuda-core test trees keep importing.
+Remove after cuda-core >= 1.2 is the oldest supported release.
+"""
+
+from cuda.bindings._test_helpers import _import_current
+
+_mempool = _import_current("mempool")
+is_windows_mcdm_device = _mempool.is_windows_mcdm_device
+xfail_if_mempool_oom = _mempool.xfail_if_mempool_oom
+
+__all__ = ["is_windows_mcdm_device", "xfail_if_mempool_oom"]

cuda_bindings/cuda/bindings/_test_helpers/pep723.py

@@ -0,0 +1,14 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Deprecated shim. Moved to cuda_python_test_helpers.pep723 in #2384 (2026-08-04).
+Kept for one release cycle so released cuda-core test trees keep importing.
+Remove after cuda-core >= 1.2 is the oldest supported release.
+"""
+
+from cuda.bindings._test_helpers import _import_current
+
+_pep723 = _import_current("pep723")
+has_package_requirements_or_skip = _pep723.has_package_requirements_or_skip
+
+__all__ = ["has_package_requirements_or_skip"]

cuda_core/tests/conftest.py

@@ -29,6 +29,30 @@
 
 pytest_plugins = ["cuda_python_test_helpers._pytest_plugin"]
 
+
+class _BanBindingsTestHelpersShimFinder:
+    """Hard-fails any import of the deprecated ``cuda.bindings._test_helpers``
+    shim (added by #2731).
+
+    That shim exists solely so already-released cuda-core <=1.1.1 test trees
+    keep working against newer cuda-bindings wheels (see #2725); it is
+    scheduled for removal once cuda-core >= 1.2 is the oldest supported
+    release. This (current, in-repo) cuda-core test suite must always use
+    cuda_python_test_helpers directly and should never exercise that shim.
+    """
+
+    def find_spec(self, fullname, path, target=None):
+        if fullname == "cuda.bindings._test_helpers" or fullname.startswith("cuda.bindings._test_helpers."):
+            raise ImportError(
+                f"Refusing to import {fullname!r}: this is a deprecated compatibility shim "
+                "(see #2731/#2725) meant only for already-released cuda-core <=1.1.1 test "
+                "trees. This test suite must import from cuda_python_test_helpers directly."
+            )
+        return None
+
+
+sys.meta_path.insert(0, _BanBindingsTestHelpersShimFinder())
+
 from helpers.constants import POOL_SIZE
 from helpers.memory import skip_if_pinned_memory_unsupported
 
@@ -184,6 +208,21 @@ def session_setup():
     multiprocessing.set_start_method("spawn", force=True)
 
 
+@pytest.fixture(scope="session", autouse=True)
+def _forbid_bindings_test_helpers_shim():
+    # Belt-and-suspenders alongside _BanBindingsTestHelpersShimFinder above:
+    # independently re-check at session end that nothing slipped the
+    # deprecated cuda.bindings._test_helpers shim into sys.modules, in case
+    # the meta path finder is ever bypassed, disabled, or removed by mistake.
+    yield
+    banned = [
+        name
+        for name in sys.modules
+        if name == "cuda.bindings._test_helpers" or name.startswith("cuda.bindings._test_helpers.")
+    ]
+    assert not banned, f"deprecated cuda.bindings._test_helpers shim was imported (see #2731): {banned}"
+
+
 @pytest.fixture
 def init_cuda():
     with _init_cuda_context() as device: