bpo-39322: Add gc.is_finalized to check if an object has been finalised by the gc (GH-17989)

2 files changed, 30 insertions, 1 deletions

diff --git a/Modules/clinic/gcmodule.c.h b/Modules/clinic/gcmodule.c.h
index 22d2aa4..72795c6 100644
--- a/Modules/clinic/gcmodule.c.h
+++ b/Modules/clinic/gcmodule.c.h
@@ -304,6 +304,15 @@ PyDoc_STRVAR(gc_is_tracked__doc__,
 #define GC_IS_TRACKED_METHODDEF    \
     {"is_tracked", (PyCFunction)gc_is_tracked, METH_O, gc_is_tracked__doc__},
 
+PyDoc_STRVAR(gc_is_finalized__doc__,
+"is_finalized($module, obj, /)\n"
+"--\n"
+"\n"
+"Returns true if the object has been already finalized by the GC.");
+
+#define GC_IS_FINALIZED_METHODDEF    \
+    {"is_finalized", (PyCFunction)gc_is_finalized, METH_O, gc_is_finalized__doc__},
+
 PyDoc_STRVAR(gc_freeze__doc__,
 "freeze($module, /)\n"
 "--\n"
@@ -373,4 +382,4 @@ gc_get_freeze_count(PyObject *module, PyObject *Py_UNUSED(ignored))
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=e40d384b1f0d513c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=bd6a8056989e2e69 input=a9049054013a1b77]*/
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 5fef114..4ad9d22 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -1870,6 +1870,25 @@ gc_is_tracked(PyObject *module, PyObject *obj)
 }
 
 /*[clinic input]
+gc.is_finalized
+
+    obj: object
+    /
+
+Returns true if the object has been already finalized by the GC.
+[clinic start generated code]*/
+
+static PyObject *
+gc_is_finalized(PyObject *module, PyObject *obj)
+/*[clinic end generated code: output=e1516ac119a918ed input=201d0c58f69ae390]*/
+{
+    if (PyObject_IS_GC(obj) && _PyGCHead_FINALIZED(AS_GC(obj))) {
+         Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
+
+/*[clinic input]
 gc.freeze
 
 Freeze all current tracked objects and ignore them for future collections.
@@ -1961,6 +1980,7 @@ static PyMethodDef GcMethods[] = {
     GC_GET_OBJECTS_METHODDEF
     GC_GET_STATS_METHODDEF
     GC_IS_TRACKED_METHODDEF
+    GC_IS_FINALIZED_METHODDEF
     {"get_referrers",  gc_get_referrers, METH_VARARGS,
         gc_get_referrers__doc__},
     {"get_referents",  gc_get_referents, METH_VARARGS,