[3.13] gh-116946: fully implement GC protocol for lzma objects (GH-138288) (#138323)

(cherry picked from commit 3ea16f9)

Author: picnixz

Modules/_lzmamodule.c

@@ -126,6 +126,9 @@ typedef struct {
     PyThread_type_lock lock;
 } Decompressor;
 
+#define Compressor_CAST(op)     ((Compressor *)(op))
+#define Decompressor_CAST(op)   ((Decompressor *)(op))
+
 /* Helper functions. */
 
 static int
@@ -857,14 +860,16 @@ Compressor_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 }
 
 static void
-Compressor_dealloc(Compressor *self)
+Compressor_dealloc(PyObject *op)
 {
+    PyTypeObject *tp = Py_TYPE(op);
+    PyObject_GC_UnTrack(op);
+    Compressor *self = Compressor_CAST(op);
     lzma_end(&self->lzs);
     if (self->lock != NULL) {
         PyThread_free_lock(self->lock);
     }
-    PyTypeObject *tp = Py_TYPE(self);
-    tp->tp_free((PyObject *)self);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
@@ -875,7 +880,7 @@ static PyMethodDef Compressor_methods[] = {
 };
 
 static int
-Compressor_traverse(Compressor *self, visitproc visit, void *arg)
+Compressor_traverse(PyObject *self, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(self));
     return 0;
@@ -925,7 +930,7 @@ static PyType_Spec lzma_compressor_type_spec = {
     // lzma_compressor_type_spec does not have Py_TPFLAGS_BASETYPE flag
     // which prevents to create a subclass.
     // So calling PyType_GetModuleState() in this file is always safe.
-    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE),
+    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_HAVE_GC),
     .slots = lzma_compressor_type_slots,
 };
 
@@ -1304,8 +1309,11 @@ _lzma_LZMADecompressor_impl(PyTypeObject *type, int format,
 }
 
 static void
-Decompressor_dealloc(Decompressor *self)
+Decompressor_dealloc(PyObject *op)
 {
+    PyTypeObject *tp = Py_TYPE(op);
+    PyObject_GC_UnTrack(op);
+    Decompressor *self = Decompressor_CAST(op);
     if(self->input_buffer != NULL)
         PyMem_Free(self->input_buffer);
 
@@ -1314,13 +1322,12 @@ Decompressor_dealloc(Decompressor *self)
     if (self->lock != NULL) {
         PyThread_free_lock(self->lock);
     }
-    PyTypeObject *tp = Py_TYPE(self);
-    tp->tp_free((PyObject *)self);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
 static int
-Decompressor_traverse(Decompressor *self, visitproc visit, void *arg)
+Decompressor_traverse(PyObject *self, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(self));
     return 0;
@@ -1372,7 +1379,7 @@ static PyType_Spec lzma_decompressor_type_spec = {
     // lzma_decompressor_type_spec does not have Py_TPFLAGS_BASETYPE flag
     // which prevents to create a subclass.
     // So calling PyType_GetModuleState() in this file is always safe.
-    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE),
+    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_HAVE_GC),
     .slots = lzma_decompressor_type_slots,
 };