Error when TORCH_STABLE_ONLY is defined in TensorBase.h (#161658)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/161658
Approved by: https://github.com/albanD

aten/src/ATen/core/TensorBase.h

@@ -1,5 +1,18 @@
 #pragma once
 
+// See https://github.com/pytorch/pytorch/issues/161660
+// This compile flag is intended to be passed in to CppExtensions that rely on
+// the stable ABI via the `extra_compile_args` argument. This is a stopgap
+// solution to ensure that non-stable libtorch APIs are not used in the extension.
+// The long term solution is to have a torch_stable target that excludes headers
+// that are not in torch/stable or torch/headeronly.
+// See test/cpp_extensions/torch_stable_test_extension/setup.py for an example
+// of how this is used.
+#ifdef TORCH_STABLE_ONLY
+#error \
+    "TensorBase.h should not be included when TORCH_STABLE_ONLY compile flag is passed"
+#endif
+
 #include <c10/core/Device.h>
 #include <c10/core/Layout.h>
 #include <c10/core/MemoryFormat.h>

test/cpp_extensions/torch_stable_test_extension/setup.py

@@ -0,0 +1,67 @@
+import distutils.command.clean
+import shutil
+from pathlib import Path
+
+from setuptools import find_packages, setup
+
+from torch.utils.cpp_extension import BuildExtension, CppExtension
+
+
+ROOT_DIR = Path(__file__).parent
+CSRC_DIR = ROOT_DIR / "torch_stable_test" / "csrc"
+
+
+class clean(distutils.command.clean.clean):
+    def run(self):
+        # Run default behavior first
+        distutils.command.clean.clean.run(self)
+
+        # Remove extension
+        for path in (ROOT_DIR / "torch_stable_test").glob("**/*.so"):
+            path.unlink()
+        # Remove build and dist and egg-info directories
+        dirs = [
+            ROOT_DIR / "build",
+            ROOT_DIR / "dist",
+            ROOT_DIR / "torch_stable_test.egg-info",
+        ]
+        for path in dirs:
+            if path.exists():
+                shutil.rmtree(str(path), ignore_errors=True)
+
+
+def get_extension():
+    extra_compile_args = {
+        "cxx": ["-fdiagnostics-color=always", "-DTORCH_STABLE_ONLY"],
+    }
+
+    sources = list(CSRC_DIR.glob("**/*.cpp"))
+
+    return [
+        CppExtension(
+            "torch_stable_test._C",
+            sources=sorted(str(s) for s in sources),
+            py_limited_api=True,
+            extra_compile_args=extra_compile_args,
+            extra_link_args=[],
+        )
+    ]
+
+
+setup(
+    name="torch_stable_test",
+    version="0.0",
+    author="PyTorch Core Team",
+    description="Test extension to verify TORCH_STABLE_ONLY flag",
+    packages=find_packages(exclude=("test",)),
+    package_data={"torch_stable_test": ["*.dll", "*.dylib", "*.so"]},
+    install_requires=[
+        "torch",
+    ],
+    ext_modules=get_extension(),
+    cmdclass={
+        "build_ext": BuildExtension.with_options(no_python_abi_suffix=True),
+        "clean": clean,
+    },
+    options={"bdist_wheel": {"py_limited_api": "cp39"}},
+)

test/cpp_extensions/torch_stable_test_extension/torch_stable_test/csrc/test_extension.cpp

@@ -0,0 +1 @@
+#include <ATen/core/TensorBase.h> // This should trigger the TORCH_STABLE_ONLY error

test/cpp_extensions/torch_stable_test_extension/torch_stable_test/test_torch_stable.py

@@ -0,0 +1,22 @@
+# Owner(s): ["module: cpp"]
+
+from pathlib import Path
+
+from torch.testing._internal.common_utils import (
+    install_cpp_extension,
+    IS_WINDOWS,
+    run_tests,
+    TestCase,
+)
+
+
+if not IS_WINDOWS:
+
+    class TestTorchStable(TestCase):
+        def test_setup_fails(self):
+            with self.assertRaisesRegex(RuntimeError, "build failed for cpp extension"):
+                install_cpp_extension(extension_root=Path(__file__).parent.parent)
+
+
+if __name__ == "__main__":
+    run_tests()