BUG: fix data race setting up within dtype cats for legacy user dtypes

ngoldbaum · ngoldbaum · commit 81200701d12d · 2025-02-06T14:40:02.000-07:00
diff --git a/numpy/_core/src/multiarray/convert_datatype.c b/numpy/_core/src/multiarray/convert_datatype.c
@@ -188,9 +188,12 @@ ensure_castingimpl_exists(PyArray_DTypeMeta *from, PyArray_DTypeMeta *to)
 NPY_NO_EXPORT PyObject *
 PyArray_GetCastingImpl(PyArray_DTypeMeta *from, PyArray_DTypeMeta *to)
 {
-    PyObject *res;
+    PyObject *res = NULL;
     if (from == to) {
-        res = Py_XNewRef((PyObject *)NPY_DT_SLOTS(from)->within_dtype_castingimpl);
+        if ((NPY_DT_SLOTS(from)->within_dtype_castingimpl) != NULL) {
+            res = Py_XNewRef(
+                    (PyObject *)NPY_DT_SLOTS(from)->within_dtype_castingimpl);
+        }
     }
     else if (PyDict_GetItemRef(NPY_DT_SLOTS(from)->castingimpls,
                                (PyObject *)to, &res) < 0) {
diff --git a/numpy/_core/src/multiarray/dtypemeta.c b/numpy/_core/src/multiarray/dtypemeta.c
@@ -1252,6 +1252,12 @@ dtypemeta_wrap_legacy_descriptor(
             return -1;
         }
     }
+    else {
+        // ensure the within dtype cast is populated for legacy user dtypes
+        if (PyArray_GetCastingImpl(dtype_class, dtype_class) == NULL) {
+            return -1;
+        }
+    }
 
     return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -1252,6 +1252,12 @@ dtypemeta_wrap_legacy_descriptor(`
`1252`	`1252`	`return -1;`
`1253`	`1253`	`}`
`1254`	`1254`	`}`
	`1255`	`+ else {`
	`1256`	`+ // ensure the within dtype cast is populated for legacy user dtypes`
	`1257`	`+ if (PyArray_GetCastingImpl(dtype_class, dtype_class) == NULL) {`
	`1258`	`+ return -1;`
	`1259`	`+ }`
	`1260`	`+ }`
`1255`	`1261`
`1256`	`1262`	`return 0;`
`1257`	`1263`	`}`