Python: Add 'limited_api' kwarg to extension_module

This commit adds a new keyword arg to extension_module() that enables
a user to target the Python Limited API, declaring the version of the
limited API that they wish to target.

Two new unittests have been added to test this functionality.

6 files changed, 129 insertions, 0 deletions

diff --git a/test cases/python/10 extmodule limited api disabled/meson.build b/test cases/python/10 extmodule limited api disabled/meson.build
new file mode 100644
index 0000000..42cd618
--- /dev/null
+++ b/test cases/python/10 extmodule limited api disabled/meson.build
@@ -0,0 +1,10 @@
+project('Python limited api disabled', 'c',
+  default_options : ['buildtype=release', 'werror=true', 'python.allow_limited_api=false'])
+
+py_mod = import('python')
+py = py_mod.find_installation()
+
+module = py.extension_module('my_module',
+  'module.c',
+  limited_api: '3.7',
+)
diff --git a/test cases/python/10 extmodule limited api disabled/module.c b/test cases/python/10 extmodule limited api disabled/module.c
new file mode 100644
index 0000000..a5d3a87
--- /dev/null
+++ b/test cases/python/10 extmodule limited api disabled/module.c
@@ -0,0 +1,17 @@
+#include <Python.h>
+
+#if defined(Py_LIMITED_API)
+#error "Py_LIMITED_API's definition by Meson should have been disabled."
+#endif
+
+static struct PyModuleDef my_module = {
+   PyModuleDef_HEAD_INIT,
+   "my_module",
+   NULL,
+   -1,
+   NULL
+};
+
+PyMODINIT_FUNC PyInit_my_module(void) {
+    return PyModule_Create(&my_module);
+}
diff --git a/test cases/python/9 extmodule limited api/limited.c b/test cases/python/9 extmodule limited api/limited.c
new file mode 100644
index 0000000..0d1c718
--- /dev/null
+++ b/test cases/python/9 extmodule limited api/limited.c
@@ -0,0 +1,19 @@
+#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
+
+static struct PyModuleDef limited_module = {
+   PyModuleDef_HEAD_INIT,
+   "limited_api_test",
+   NULL,
+   -1,
+   NULL
+};
+
+PyMODINIT_FUNC PyInit_limited(void) {
+    return PyModule_Create(&limited_module);
+}
diff --git a/test cases/python/9 extmodule limited api/meson.build b/test cases/python/9 extmodule limited api/meson.build
new file mode 100644
index 0000000..68afc96
--- /dev/null
+++ b/test cases/python/9 extmodule limited api/meson.build
@@ -0,0 +1,16 @@
+project('Python limited api', 'c',
+  default_options : ['buildtype=release', 'werror=true'])
+
+py_mod = import('python')
+py = py_mod.find_installation()
+
+ext_mod_limited = py.extension_module('limited',
+  'limited.c',
+  limited_api: '3.7',
+  install: true,
+)
+
+ext_mod = py.extension_module('not_limited',
+  'not_limited.c',
+  install: true,
+)
diff --git a/test cases/python/9 extmodule limited api/not_limited.c b/test cases/python/9 extmodule limited api/not_limited.c
new file mode 100644
index 0000000..105dbb8
--- /dev/null
+++ b/test cases/python/9 extmodule limited api/not_limited.c
@@ -0,0 +1,59 @@
+#include <Python.h>
+#include <stdio.h>
+
+#ifdef Py_LIMITED_API
+#error Py_LIMITED_API must not be defined.
+#endif
+
+/* This function explicitly calls functions whose declaration is elided when
+ * Py_LIMITED_API is defined. This is to test that the linker is actually
+ * linking to the right version of the library on Windows. */
+static PyObject *meth_not_limited(PyObject *self, PyObject *args)
+{
+    PyObject *list;
+    Py_ssize_t size;
+
+    if (!PyArg_ParseTuple(args, "o", &  list))
+        return NULL;
+
+    if (!PyList_Check(list)) {
+        PyErr_Format(PyExc_TypeError, "expected 'list'");
+        return NULL;
+    }
+
+    /* PyList_GET_SIZE and PyList_GET_ITEM are only available if Py_LIMITED_API
+     * is not defined. It seems likely that they will remain excluded from the
+     * limited API as their checked counterparts (PyList_GetSize and
+     * PyList_GetItem) are made available in that mode instead. */
+    size = PyList_GET_SIZE(list);
+    for(Py_ssize_t i = 0; i < size; ++i) {
+        PyObject *element = PyList_GET_ITEM(list, i);
+        if (element == NULL) {
+            return NULL;
+        }
+
+        if(PyObject_Print(element, stdout, Py_PRINT_RAW) == -1) {
+            return NULL;
+        }
+    }
+
+    Py_RETURN_NONE;
+}
+
+static struct PyMethodDef not_limited_methods[] = {
+    { "not_limited", meth_not_limited, METH_VARARGS,
+     "Calls functions whose declaration is elided by Py_LIMITED_API" },
+    { NULL, NULL, 0, NULL }
+};
+
+static struct PyModuleDef not_limited_module = {
+   PyModuleDef_HEAD_INIT,
+   "not_limited_api_test",
+   NULL,
+   -1,
+   not_limited_methods
+};
+
+PyMODINIT_FUNC PyInit_not_limited(void) {
+    return PyModule_Create(&not_limited_module);
+}
diff --git a/test cases/python/9 extmodule limited api/test.json b/test cases/python/9 extmodule limited api/test.json
new file mode 100644
index 0000000..06a1706
--- /dev/null
+++ b/test cases/python/9 extmodule limited api/test.json
@@ -0,0 +1,8 @@
+{
+  "installed": [
+    {"type": "python_limited_lib", "file": "usr/@PYTHON_PLATLIB@/limited"},
+    {"type": "py_limited_implib", "file": "usr/@PYTHON_PLATLIB@/limited"},
+    {"type": "python_lib", "file": "usr/@PYTHON_PLATLIB@/not_limited"},
+    {"type": "py_implib", "file": "usr/@PYTHON_PLATLIB@/not_limited"}
+  ]
+}