TST: add test package with internal shared library, installed in site-packages

Author: rgommers

tests/packages/sharedlib-in-package/meson.build

@@ -0,0 +1,9 @@
+# SPDX-FileCopyrightText: 2022 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+project('sharedlib-in-package', 'c', version: '1.0.0')
+
+py = import('python').find_installation(pure: false)
+
+subdir('mypkg')

tests/packages/sharedlib-in-package/mypkg/__init__.py

@@ -0,0 +1,32 @@
+# SPDX-FileCopyrightText: 2024 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+import os
+
+
+def _enable_sharedlib_loading():
+    """Ensure the `examplelib` shared library on Windows can be loaded
+
+    This shared library is installed alongside this __init__.py file. Due to
+    lack of RPATH support, Windows cannot find shared libraries installed
+    within wheels unless we either amend the DLL search path or pre-load the
+    DLL.
+
+    .. note::
+
+        `os.add_dll_directory` is only available for Python >=3.8, and with
+        the Conda `python` packages only works as advertised for >=3.10.
+        If you require support for older versions, pre-loading the DLL
+        with `ctypes.WinDLL` may be preferred (the SciPy code base has an
+        example of this).
+    """
+    if os.name == "nt":
+        basedir = os.path.dirname(__file__)
+        os.add_dll_directory(basedir)
+
+
+_enable_sharedlib_loading()
+
+
+from ._example import example_sum

tests/packages/sharedlib-in-package/mypkg/_examplemod.c

@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include <Python.h>
+
+#include "examplelib.h"
+
+static PyObject* example_sum(PyObject* self, PyObject *args)
+{
+    int a, b;
+    if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
+        return NULL;
+    }
+
+    long result = sum(a, b);
+
+    return PyLong_FromLong(result);
+}
+
+static PyMethodDef methods[] = {
+    {"example_sum", (PyCFunction)example_sum, METH_VARARGS, NULL},
+    {NULL, NULL, 0, NULL},
+};
+
+static struct PyModuleDef module = {
+    PyModuleDef_HEAD_INIT,
+    "_example",
+    NULL,
+    -1,
+    methods,
+};
+
+PyMODINIT_FUNC PyInit__example(void)
+{
+    return PyModule_Create(&module);
+}

tests/packages/sharedlib-in-package/mypkg/examplelib.c

@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include "mypkg_dll.h"
+
+MYPKG_DLL int sum(int a, int b) {
+	return a + b;
+}

tests/packages/sharedlib-in-package/mypkg/examplelib.h

@@ -0,0 +1,7 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include "mypkg_dll.h"
+
+MYPKG_DLL int sum(int a, int b);

tests/packages/sharedlib-in-package/mypkg/meson.build

@@ -0,0 +1,38 @@
+# SPDX-FileCopyrightText: 2022 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+if meson.get_compiler('c').get_id() in ['msvc', 'clang-cl', 'intel-cl']
+  export_dll_args = ['-DMYPKG_DLL_EXPORTS']
+  import_dll_args = ['-DMYPKG_DLL_IMPORTS']
+else
+  export_dll_args = []
+  import_dll_args = []
+endif
+
+example_lib = shared_library(
+    'examplelib',
+    'examplelib.c',
+    c_args: export_dll_args,
+    install: true,
+    install_dir: py.get_install_dir() / 'mypkg',
+)
+
+example_lib_dep = declare_dependency(
+  compile_args: import_dll_args,
+  link_with: example_lib,
+)
+
+py.extension_module(
+    '_example',
+    '_examplemod.c',
+    dependencies: example_lib_dep,
+    install: true,
+    subdir: 'mypkg',
+    install_rpath: '$ORIGIN',
+)
+
+py.install_sources(
+    ['__init__.py'],
+    subdir: 'mypkg',
+)

tests/packages/sharedlib-in-package/mypkg/mypkg_dll.h

@@ -0,0 +1,19 @@
+#pragma once
+
+// MYPKG_DLL
+// inspired by https://github.com/abseil/abseil-cpp/blob/20240116.2/absl/base/config.h#L736-L753
+// and https://github.com/scipy/scipy/blob/9ded83b51099eee745418ccbb30196db96c81f3f/scipy/_build_utils/src/scipy_dll.h
+//
+// When building the `examplelib` DLL, this macro expands to `__declspec(dllexport)`
+// so we can annotate symbols appropriately as being exported. When used in
+// headers consuming a DLL, this macro expands to `__declspec(dllimport)` so
+// that consumers know the symbol is defined inside the DLL. In all other cases,
+// the macro expands to nothing.
+// Note: MYPKG_DLL_{EX,IM}PORTS are set in mypkg/meson.build
+#if defined(MYPKG_DLL_EXPORTS)
+    #define MYPKG_DLL __declspec(dllexport)
+#elif defined(MYPKG_DLL_IMPORTS)
+    #define MYPKG_DLL __declspec(dllimport)
+#else
+    #define MYPKG_DLL
+#endif

tests/packages/sharedlib-in-package/pyproject.toml

@@ -0,0 +1,7 @@
+# SPDX-FileCopyrightText: 2022 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+[build-system]
+build-backend = 'mesonpy'
+requires = ['meson-python']

tests/test_wheel.py

@@ -161,6 +161,13 @@ def test_local_lib(venv, wheel_link_against_local_lib):
     assert int(output) == 3
 
 
+@pytest.mark.skipif(MESON_VERSION < (0, 64, 0), reason='Meson version too old')
+def test_sharedlib_in_package(venv, wheel_sharedlib_in_package):
+    venv.pip('install', wheel_sharedlib_in_package)
+    output = venv.python('-c', 'import mypkg; print(mypkg.example_sum(2, 5))')
+    assert int(output) == 7
+
+
 @pytest.mark.skipif(sys.platform not in {'linux', 'darwin'}, reason='Not supported on this platform')
 def test_rpath(wheel_link_against_local_lib, tmp_path):
     artifact = wheel.wheelfile.WheelFile(wheel_link_against_local_lib)