bpo-26868: Fix example usage of PyModule_AddObject. (#15725)

* Add a note to the PyModule_AddObject docs.

* Correct example usages of PyModule_AddObject.

* Whitespace.

* Clean up wording.

* 📜🤖 Added by blurb_it.

* First code review.

* Add < 0 in the tests with PyModule_AddObject
This commit is contained in:
Brandt Bucher 2019-09-12 05:11:20 -07:00 committed by Stéphane Wirtel
parent 967b84c913
commit 224b8aaa7e
9 changed files with 74 additions and 13 deletions

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@ -417,7 +417,22 @@ state:
Add an object to *module* as *name*. This is a convenience function which can
be used from the module's initialization function. This steals a reference to
*value*. Return ``-1`` on error, ``0`` on success.
*value* on success. Return ``-1`` on error, ``0`` on success.
.. note::
Unlike other functions that steal references, ``PyModule_AddObject()`` only
decrements the reference count of *value* **on success**.
This means that its return value must be checked, and calling code must
:c:func:`Py_DECREF` *value* manually on error. Example usage::
Py_INCREF(spam);
if (PyModule_AddObject(module, "spam", spam) < 0) {
Py_DECREF(module);
Py_DECREF(spam);
return NULL;
}
.. c:function:: int PyModule_AddIntConstant(PyObject *module, const char *name, long value)

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@ -209,7 +209,7 @@ usually declare a static object variable at the beginning of your file::
static PyObject *SpamError;
and initialize it in your module's initialization function (:c:func:`PyInit_spam`)
with an exception object (leaving out the error checking for now)::
with an exception object::
PyMODINIT_FUNC
PyInit_spam(void)
@ -221,8 +221,14 @@ with an exception object (leaving out the error checking for now)::
return NULL;
SpamError = PyErr_NewException("spam.error", NULL, NULL);
Py_INCREF(SpamError);
PyModule_AddObject(m, "error", SpamError);
Py_XINCREF(SpamError);
if (PyModule_AddObject(m, "error", SpamError) < 0) {
Py_XDECREF(SpamError);
Py_CLEAR(SpamError);
Py_DECREF(m);
return NULL;
}
return m;
}
@ -1261,8 +1267,12 @@ function must take care of initializing the C API pointer array::
/* Create a Capsule containing the API pointer array's address */
c_api_object = PyCapsule_New((void *)PySpam_API, "spam._C_API", NULL);
if (c_api_object != NULL)
PyModule_AddObject(m, "_C_API", c_api_object);
if (PyModule_AddObject(m, "_C_API", c_api_object) < 0) {
Py_XDECREF(c_api_object);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -179,7 +179,12 @@ This initializes the :class:`Custom` type, filling in a number of members
to the appropriate default values, including :attr:`ob_type` that we initially
set to *NULL*. ::
PyModule_AddObject(m, "Custom", (PyObject *) &CustomType);
Py_INCREF(&CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
Py_DECREF(&CustomType);
PY_DECREF(m);
return NULL;
}
This adds the type to the module dictionary. This allows us to create
:class:`Custom` instances by calling the :class:`Custom` class:
@ -864,7 +869,12 @@ function::
return NULL;
Py_INCREF(&SubListType);
PyModule_AddObject(m, "SubList", (PyObject *) &SubListType);
if (PyModule_AddObject(m, "SubList", (PyObject *) &SubListType) < 0) {
Py_DECREF(&SubListType);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -35,6 +35,11 @@ PyInit_custom(void)
return NULL;
Py_INCREF(&CustomType);
PyModule_AddObject(m, "Custom", (PyObject *) &CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
Py_DECREF(&CustomType);
PY_DECREF(m);
return NULL;
}
return m;
}

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@ -128,6 +128,11 @@ PyInit_custom2(void)
return NULL;
Py_INCREF(&CustomType);
PyModule_AddObject(m, "Custom", (PyObject *) &CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
Py_DECREF(&CustomType);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -179,6 +179,11 @@ PyInit_custom3(void)
return NULL;
Py_INCREF(&CustomType);
PyModule_AddObject(m, "Custom", (PyObject *) &CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
Py_DECREF(&CustomType);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -193,6 +193,11 @@ PyInit_custom4(void)
return NULL;
Py_INCREF(&CustomType);
PyModule_AddObject(m, "Custom", (PyObject *) &CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
Py_DECREF(&CustomType);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -59,6 +59,11 @@ PyInit_sublist(void)
return NULL;
Py_INCREF(&SubListType);
PyModule_AddObject(m, "SubList", (PyObject *) &SubListType);
if (PyModule_AddObject(m, "SubList", (PyObject *) &SubListType) < 0) {
Py_DECREF(&SubListType);
Py_DECREF(m);
return NULL;
}
return m;
}

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@ -0,0 +1 @@
Fix example usage of :c:func:`PyModule_AddObject` to properly handle errors.