tests: add python limited_api tests for find_installation and `de…

…pendency`

Check that extension_modules and dependencies inherit the installation's
limited_api value by default but can override it.

Also test the end-to-end case of compiling a library and linking it with
an extension, both compiled against the Limited API. This is similar to
how nanobind is used.

test cases/python/11 extmodule limited api lib/meson.build

@@ -0,0 +1,28 @@
+# Test that we can build a library that uses the limited API
+# and link it to an extension module.
+
+project('Python limited api lib', 'c',
+  default_options : ['buildtype=release', 'werror=true'])
+
+py_mod = import('python')
+py = py_mod.find_installation(limited_api: '3.7')
+py_dep = py.dependency(required: true)
+
+nanolib = static_library(
+    'nanolib',
+    'nanolib.c',
+    dependencies: [py_dep],
+)
+
+ext_mod = py.extension_module('mymodule',
+  'module.c',
+  install: true,
+  link_with: [nanolib],
+)
+
+test('load-test',
+  py,
+  args: [files('test_module.py')],
+  env: { 'PYTHONPATH': meson.current_build_dir() },
+  workdir: meson.current_source_dir()
+)

test cases/python/11 extmodule limited api lib/module.c

@@ -0,0 +1,27 @@
+#include <Python.h>
+
+#ifndef Py_LIMITED_API
+#error Py_LIMITED_API must be defined.
+#elif Py_LIMITED_API != 0x03070000
+#error Wrong value for Py_LIMITED_API
+#endif
+
+PyObject *
+hello(PyObject * Py_UNUSED(self), PyObject * Py_UNUSED(args));
+
+static struct PyMethodDef methods[] = {
+    { "hello", hello, METH_NOARGS, NULL },
+    { NULL, NULL, 0, NULL },
+};
+
+static struct PyModuleDef mymodule = {
+   PyModuleDef_HEAD_INIT,
+   "mymodule",
+   NULL,
+   -1,
+   methods
+};
+
+PyMODINIT_FUNC PyInit_mymodule(void) {
+    return PyModule_Create(&mymodule);
+}

test cases/python/11 extmodule limited api lib/nanolib.c

@@ -0,0 +1,12 @@
+#include <Python.h>
+
+#ifndef Py_LIMITED_API
+#error Py_LIMITED_API must be defined.
+#elif Py_LIMITED_API != 0x03070000
+#error Wrong value for Py_LIMITED_API
+#endif
+
+PyObject *
+hello(PyObject * Py_UNUSED(self), PyObject * Py_UNUSED(args)) {
+    return PyUnicode_FromString("hello world");
+}

test cases/python/11 extmodule limited api lib/test.json

@@ -0,0 +1,6 @@
+{
+  "installed": [
+    {"type": "python_limited_lib", "file": "usr/@PYTHON_PLATLIB@/mymodule"},
+    {"type": "py_limited_implib", "file": "usr/@PYTHON_PLATLIB@/mymodule"}
+  ]
+}

test cases/python/11 extmodule limited api lib/test_module.py

@@ -0,0 +1,6 @@
+from mymodule import hello
+
+def test_hello():
+    assert hello() == "hello world"
+
+test_hello()

test cases/python/9 extmodule limited api/meson.build

@@ -21,3 +21,32 @@ test('load-test',
   env: { 'PYTHONPATH': meson.current_build_dir() },
   workdir: meson.current_source_dir()
 )
+
+# Test inheritance and override of limited_api
+
+py_limited = py_mod.find_installation(limited_api: '3.7')
+
+py_limited.extension_module('limited_inherit',
+  'limited.c',
+)
+
+py_limited.extension_module('not_limited_override',
+  'not_limited.c',
+  limited_api: '',
+)
+
+py_dep_limited = py.dependency(required: true, limited_api: '3.7')
+
+static_library(
+    'limited_dependency',
+    'limited.c',
+    dependencies: [py_dep_limited],
+)
+
+py_dep_inherit = py_limited.dependency(required: true)
+
+static_library(
+    'limited_dependency_inherit',
+    'limited.c',
+    dependencies: [py_dep_inherit],
+)