BUG: fix memory leaks found by valgrind

Author: ngoldbaum

numpy/_core/src/multiarray/arraytypes.c.src

@@ -4222,6 +4222,7 @@ NPY_NO_EXPORT PyArray_Descr *
 PyArray_DescrFromType(int type)
 {
     PyArray_Descr *ret = NULL;
+    npy_bool is_stringdtype = (type == NPY_VSTRING || type == NPY_VSTRINGLTR);
 
     if (type < 0) {
         /*
@@ -4233,7 +4234,7 @@ PyArray_DescrFromType(int type)
          */
         ret = NULL;
     }
-    else if (type == NPY_VSTRING || type == NPY_VSTRINGLTR) {
+    else if  (is_stringdtype) {
         ret = (PyArray_Descr *)new_stringdtype_instance(NULL, 1);
     }
     // builtin legacy dtypes
@@ -4280,7 +4281,7 @@ PyArray_DescrFromType(int type)
         PyErr_SetString(PyExc_ValueError,
                 "Invalid data-type for array");
     }
-    else {
+    else if (!is_stringdtype) {
         Py_INCREF(ret);
     }
 

numpy/_core/src/multiarray/descriptor.c

@@ -2025,6 +2025,7 @@ arraydescr_dealloc(PyArray_Descr *self)
 {
     Py_XDECREF(self->typeobj);
     if (!PyDataType_ISLEGACY(self)) {
+        Py_TYPE(self)->tp_free((PyObject *)self);
         return;
     }
     _PyArray_LegacyDescr *lself = (_PyArray_LegacyDescr *)self;