TST: fix test and reorganize

Rework the dependencies between the Python extension module and the
package libraries so that they can be loaded with a single additional
RPATH entry for each. The previous dependencies required two RPATH
entries to be added to the extension module to find the two libraries
installed in two different paths, however setting two RPATH entries is
not possible via install_rpath.  Meson version 1.6.0 or later is
required for insrall_rpath to be present in meson introspection data.

Reorganizes the test package to a flatter layout that helps
visualizing all the parts involved in the test.

Author: dnicolodi

tests/packages/link-against-local-lib/meson.build

@@ -9,7 +9,7 @@ if meson.get_compiler('c').get_id() in ['msvc', 'clang-cl', 'intel-cl']
     link_args = ['-DEXAMPLE_DLL_IMPORTS']
 else
     lib_compile_args = []
-    link_args = ['-Wl,-rpath,custom-rpath']
+    link_args = ['-Wl,-rpath,rpath-from-linker-arguments']
 endif
 
 subdir('lib')
@@ -26,6 +26,7 @@ py.extension_module(
     'examplemod.c',
     link_with: example_lib,
     link_args: link_args,
+    install_rpath: 'custom-rpath',
     install: true,
     subdir: 'example',
 )

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

@@ -45,7 +45,7 @@ def _append_to_sharedlib_load_path():
 # end-literalinclude
 
 
-from ._example import example_prod, example_sum  #noqa: E402
+from ._example import prodsum  # noqa: E402
 
 
-__all__ = ['example_prod', 'example_sum']
+__all__ = ['prodsum']

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

@@ -4,36 +4,23 @@
 
 #include <Python.h>
 
-#include "examplelib.h"
-#include "examplelib2.h"
+#include "lib.h"
 
-static PyObject* example_sum(PyObject* self, PyObject *args)
+static PyObject* example_prodsum(PyObject* self, PyObject *args)
 {
-    int a, b;
-    if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
-        return NULL;
-    }
+    int a, b, x;
 
-    long result = sum(a, b);
-
-    return PyLong_FromLong(result);
-}
-
-static PyObject* example_prod(PyObject* self, PyObject *args)
-{
-    int a, b;
-    if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
+    if (!PyArg_ParseTuple(args, "iii", &a, &b, &x)) {
         return NULL;
     }
 
-    long result = prod(a, b);
+    long result = prodsum(a, b, x);
 
     return PyLong_FromLong(result);
 }
 
 static PyMethodDef methods[] = {
-    {"example_prod", (PyCFunction)example_prod, METH_VARARGS, NULL},
-    {"example_sum", (PyCFunction)example_sum, METH_VARARGS, NULL},
+    {"prodsum", (PyCFunction)example_prodsum, METH_VARARGS, NULL},
     {NULL, NULL, 0, NULL},
 };
 

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

@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include "lib.h"
+#include "sublib.h"
+
+int prodsum(int a, int b, int x) {
+    return prod(a,  x) + b;
+}

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

@@ -0,0 +1,13 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#if defined(MYPKG_DLL_EXPORTS)
+    #define EXPORT __declspec(dllexport)
+#elif defined(MYPKG_DLL_IMPORTS)
+    #define EXPORT __declspec(dllimport)
+#else
+    #define EXPORT
+#endif
+
+EXPORT int prodsum(int a, int b, int x);

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

@@ -10,29 +10,42 @@ else
     import_dll_args = []
 endif
 
-example_lib = shared_library(
-    'examplelib',
-    'examplelib.c',
+sublib = shared_library(
+    'sublib',
+    'sublib.c',
     c_args: export_dll_args,
     install: true,
-    install_dir: py.get_install_dir() / 'mypkg',
+    install_dir: py.get_install_dir() / 'mypkg/sub',
 )
 
-example_lib_dep = declare_dependency(
+sublib_dep = declare_dependency(
     compile_args: import_dll_args,
-    link_with: example_lib,
+    link_with: sublib,
+)
+
+lib = shared_library(
+    'lib',
+    'lib.c',
+    dependencies: sublib_dep,
+    c_args: export_dll_args,
+    install_rpath: '$ORIGIN/sub',
+    install: true,
+    install_dir: py.get_install_dir() / 'mypkg',
 )
 
-subdir('sub')
+lib_dep = declare_dependency(
+    compile_args: import_dll_args,
+    link_with: lib,
+)
 
 py.extension_module(
     '_example',
     '_examplemod.c',
-    dependencies: [example_lib_dep, example_lib2_dep],
+    dependencies: lib_dep,
     include_directories: 'sub',
     install: true,
     subdir: 'mypkg',
-    install_rpath: '$ORIGIN',
+    install_rpath: build_machine.system() == 'darwin' ? '@loader_path' : '$ORIGIN',
 )
 
 py.install_sources(

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

@@ -2,8 +2,8 @@
 //
 // SPDX-License-Identifier: MIT
 
-#include "mypkg_dll.h"
+#include "sublib.h"
 
-MYPKG_DLL int prod(int a, int b) {
+int prod(int a, int b) {
     return a * b;
 }

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

@@ -0,0 +1,13 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#if defined(MYPKG_DLL_EXPORTS)
+    #define EXPORT __declspec(dllexport)
+#elif defined(MYPKG_DLL_IMPORTS)
+    #define EXPORT __declspec(dllimport)
+#else
+    #define EXPORT
+#endif
+
+EXPORT int prod(int a, int b);

tests/packages/sharedlib-in-package/mypkg/sub/examplelib2.h

@@ -178,15 +178,14 @@ def test_local_lib(venv, wheel_link_against_local_lib):
     assert int(output) == 3
 
 
+@pytest.mark.skipif(MESON_VERSION < (1, 6, 0), reason='meson 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
-    output = venv.python('-c', 'import mypkg; print(mypkg.example_prod(6, 7))')
-    assert int(output) == 42
+    output = venv.python('-c', 'import mypkg; print(mypkg.prodsum(2, 3, 4))')
+    assert int(output) == 11
 
 
-@pytest.mark.skipif(MESON_VERSION < (1, 3, 0), reason='Meson version too old')
+@pytest.mark.skipif(MESON_VERSION < (1, 3, 0), reason='meson too old')
 def test_link_library_in_subproject(venv, wheel_link_library_in_subproject):
     venv.pip('install', wheel_link_library_in_subproject)
     output = venv.python('-c', 'import foo; print(foo.example_sum(3, 6))')
@@ -199,7 +198,11 @@ def test_rpath(wheel_link_against_local_lib, tmp_path):
     artifact.extractall(tmp_path)
 
     origin = '@loader_path' if sys.platform == 'darwin' else '$ORIGIN'
-    expected = {f'{origin}/../.link_against_local_lib.mesonpy.libs', 'custom-rpath',}
+    expected = {f'{origin}/../.link_against_local_lib.mesonpy.libs', 'rpath-from-linker-arguments',}
+
+    # ``install_rpath`` is supported starting with meson 1.6.0
+    if MESON_VERSION >= (1, 6, 0):
+        expected.add('custom-rpath')
 
     rpath = set(mesonpy._rpath._get_rpath(tmp_path / 'example' / f'_example{EXT_SUFFIX}'))
     # Verify that rpath is a superset of the expected one: linking to