python · methane · Feb 23, 2019 · Feb 17, 2019 · Feb 17, 2019 · Feb 17, 2019
diff --git a/Doc/library/gc.rst b/Doc/library/gc.rst
@@ -63,11 +63,14 @@ The :mod:`gc` module provides the following functions:
   Return the debugging flags currently set.


-.. function:: get_objects()
+.. function:: get_objects(generation=None)

   Returns a list of all objects tracked by the collector, excluding the list
-   returned.
+   returned. If *generation* is not None, return only the objects tracked by
+   the collector that are in that generation.

+   .. versionchanged:: 3.8
+      New *generation* parameter.

 .. function:: get_stats()


diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
@@ -163,6 +163,15 @@ gettext
 Added :func:`~gettext.pgettext` and its variants.
 (Contributed by Franz Glasner, Éric Araujo, and Cheryl Sabella in :issue:`2504`.)

+
+gc
+--
+
+:func:`~gc.get_objects` can now receive an optional *generation* parameter
+indicating a generation to get objects from. Contributed in
+:issue:`36016` by Pablo Galindo.
+
+
 gzip
 ----


diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
@@ -766,6 +766,38 @@ def test_freeze(self):
        gc.unfreeze()
        self.assertEqual(gc.get_freeze_count(), 0)

+    def test_get_objects(self):
+        gc.collect()
+        l = []
+        l.append(l)
+        self.assertIn(l, gc.get_objects(generation=0))
+        self.assertNotIn(l, gc.get_objects(generation=1))
+        self.assertNotIn(l, gc.get_objects(generation=2))
+        gc.collect(generation=0)
+        self.assertNotIn(l, gc.get_objects(generation=0))
+        self.assertIn(l, gc.get_objects(generation=1))
+        self.assertNotIn(l, gc.get_objects(generation=2))
+        gc.collect(generation=1)
+        self.assertNotIn(l, gc.get_objects(generation=0))
+        self.assertNotIn(l, gc.get_objects(generation=1))
+        self.assertIn(l, gc.get_objects(generation=2))
+        gc.collect(generation=2)
+        self.assertNotIn(l, gc.get_objects(generation=0))
+        self.assertNotIn(l, gc.get_objects(generation=1))
+        self.assertIn(l, gc.get_objects(generation=2))
+        del l
+        gc.collect()
+
+    def test_get_objects_arguments(self):
+        gc.collect()
+        self.assertEqual(len(gc.get_objects()),
+                         len(gc.get_objects(generation=None)))
+
+        self.assertRaises(ValueError, gc.get_objects, 1000)
+        self.assertRaises(ValueError, gc.get_objects, -1000)
+        self.assertRaises(TypeError, gc.get_objects, "1")
+        self.assertRaises(TypeError, gc.get_objects, 1.234)
+

 class GCCallbackTests(unittest.TestCase):
    def setUp(self):

diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-02-17-20-23-54.bpo-36016.5Hns-f.rst b/Misc/NEWS.d/next/Core and Builtins/2019-02-17-20-23-54.bpo-36016.5Hns-f.rst
@@ -0,0 +1,2 @@
+``gc.get_objects`` can now receive an optional parameter indicating a
+generation to get objects from. Patch by Pablo Galindo.
diff --git a/Modules/clinic/gcmodule.c.h b/Modules/clinic/gcmodule.c.h
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
@@ -1502,27 +1502,61 @@ gc_get_referents(PyObject *self, PyObject *args)

 /*[clinic input]
 gc.get_objects
+    generation: Py_ssize_t(accept={int, NoneType}, c_default="-1") = None
+        Generation to extract the objects from.

 Return a list of objects tracked by the collector (excluding the list returned).
+
+If generation is not None, return only the objects tracked by the collector
+that are in that generation.
 [clinic start generated code]*/

 static PyObject *
-gc_get_objects_impl(PyObject *module)
-/*[clinic end generated code: output=fcb95d2e23e1f750 input=9439fe8170bf35d8]*/
+gc_get_objects_impl(PyObject *module, Py_ssize_t generation)
+/*[clinic end generated code: output=48b35fea4ba6cb0e input=ef7da9df9806754c]*/
 {
    int i;
    PyObject* result;

    result = PyList_New(0);
-    if (result == NULL)
+    if (result == NULL) {
        return NULL;
+    }
+
+    /* If generation is passed, we extract only that generation */
+    if (generation != -1) { 
+        if (generation >= NUM_GENERATIONS) {
+            PyErr_Format(PyExc_ValueError,
+                         "generation parameter must be less than the number of "
+                         "available generations (%i)",
+                          NUM_GENERATIONS);
+            goto error;
+        }
+
+        if (generation < 0) {
+            PyErr_SetString(PyExc_ValueError,
+                            "generation parameter cannot be negative");
+            goto error;
+        }
+
+        if (append_objects(result, GEN_HEAD(generation))) {
+            goto error;
+        }
+
+        return result;
+    }
+
+    /* If generation is not passed or None, get all objects from all generations */
    for (i = 0; i < NUM_GENERATIONS; i++) {
        if (append_objects(result, GEN_HEAD(i))) {
-            Py_DECREF(result);
-            return NULL;
+            goto error;
        }
    }
    return result;
+
+error:
+    Py_DECREF(result);
+    return NULL;
 }

 /*[clinic input]
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		``gc.get_objects`` can now receive an optional parameter indicating a
		generation to get objects from. Patch by Pablo Galindo.