More refcounting fixes

src/runtime/capi.cpp

@@ -1470,6 +1470,11 @@ extern "C" PyObject* PyThreadState_GetDict(void) noexcept {
     return dict;
 }
 
+extern "C" void PyThreadState_Clear(PyThreadState* tstate) noexcept {
+    assert(tstate == NULL);
+    Py_CLEAR(cur_thread_state.dict);
+}
+
 extern "C" int _PyOS_URandom(void* buffer, Py_ssize_t size) noexcept {
     if (size < 0) {
         PyErr_Format(PyExc_ValueError, "negative argument not allowed");

src/runtime/list.cpp

@@ -87,6 +87,7 @@ extern "C" Box* listRepr(BoxedList* self) {
             assert(r->cls == str_cls);
             BoxedString* s = static_cast<BoxedString*>(r);
             chars.insert(chars.end(), s->s().begin(), s->s().end());
+            Py_DECREF(s);
         }
         chars.push_back(']');
     } catch (ExcInfo e) {
@@ -542,13 +543,21 @@ static inline void listSetitemSliceInt64(BoxedList* self, i64 start, i64 stop, i
     int remaining_elts = self->size - stop;
     self->ensure(delts);
 
+    // XXX should make a copy here in case a destructor gets run
+    for (int i = start; i < step; i++) {
+        Py_CLEAR(self->elts->elts[i]);
+    }
+
     memmove(self->elts->elts + start + v_size, self->elts->elts + stop, remaining_elts * sizeof(Box*));
     for (int i = 0; i < v_size; i++) {
         Box* r = v_elts[i];
+        Py_INCREF(r);
         self->elts->elts[start + i] = r;
     }
 
     self->size += delts;
+
+    Py_XDECREF(v_as_seq);
 }
 
 extern "C" Box* listSetitemSlice(BoxedList* self, BoxedSlice* slice, Box* v) {
@@ -1246,12 +1255,15 @@ extern "C" int PyList_SetSlice(PyObject* a, Py_ssize_t ilow, Py_ssize_t ihigh, P
     BoxedList* l = (BoxedList*)a;
     ASSERT(PyList_Check(l), "%s", l->cls->tp_name);
 
+    // TODO should just call list_ass_slice
     try {
-        BoxedSlice* slice = (BoxedSlice*)createSlice(boxInt(ilow), boxInt(ihigh), None);
+        BoxedSlice* slice = (BoxedSlice*)createSlice(autoDecref(boxInt(ilow)), autoDecref(boxInt(ihigh)), None);
         if (v)
-            listSetitemSlice(l, slice, v);
+            autoDecref(listSetitemSlice(l, slice, v));
         else
-            listDelitemSlice(l, slice);
+            autoDecref(listDelitemSlice(l, slice));
+
+        Py_DECREF(slice);
         return 0;
     } catch (ExcInfo e) {
         setCAPIException(e);

src/runtime/types.cpp

@@ -262,7 +262,7 @@ BoxedString* Box::reprICAsString() {
     Box* r = this->reprIC();
 
     if (isSubclass(r->cls, unicode_cls)) {
-        r = PyUnicode_AsASCIIString(r);
+        r = PyUnicode_AsASCIIString(autoDecref(r));
         checkAndThrowCAPIException();
     }
     if (r->cls != str_cls) {
@@ -4334,6 +4334,7 @@ extern "C" void Py_Finalize() noexcept {
     PyOS_FiniInterrupts();
     PyType_ClearCache();
     _PyUnicode_Fini();
+    PyThreadState_Clear(NULL);
     for (auto b : constants) {
         Py_DECREF(b);
     }

src/runtime/types.h

@@ -983,6 +983,9 @@ class BoxedSlice : public Box {
 public:
     Box* start, *stop, *step;
     BoxedSlice(Box* lower, Box* upper, Box* step) : start(lower), stop(upper), step(step) {
+        Py_INCREF(lower);
+        Py_INCREF(upper);
+        Py_INCREF(step);
         ASSERT(lower->cls == none_cls || lower->cls == int_cls, "slice objects are not gc-aware (like in CPython)");
         ASSERT(upper->cls == none_cls || upper->cls == int_cls, "slice objects are not gc-aware (like in CPython)");
         ASSERT(step->cls == none_cls || step->cls == int_cls, "slice objects are not gc-aware (like in CPython)");