check hasattr on the type, not the instance.

hasattr on the instance triggers __getattr__ which carries very undesirable
effects, such as running Ops on a donated buffer.

Long term, we may want to audit all uses of hasattr on TensorFlow instances
that overrides __getattr__ in nontrival (e.g. running tf Ops) ways. They will
almost always cause trouble here and there because TensorFlow is quite far
from being able guarantee if an Op returns or consumes is actually valid in all cases. Things will improve give it time, but if we can avoid such strong assumptions the system tend to get more robust.

PiperOrigin-RevId: 578261984

tensorflow/python/checkpoint/async_checkpoint_helper.py

@@ -263,10 +263,10 @@ def _ensure_initialized(self):
     # custom __getattr__ code, see b/152031870 for context.
     for t in all_trackables:
       # Special case 1: TPU Embedding, populate object_map here
-    # Special case 1: Handle TPU Embedding by addnig a dummy instance to the
-    # object map. Also add TPUEmbedding to separate list for special handling
-    # with values copy.
-      if hasattr(t, _TPU_EMBEDDING_ATTR):
+      # Special case 1: Handle TPU Embedding by addnig a dummy instance to the
+      # object map. Also add TPUEmbedding to separate list for special handling
+      # with values copy.
+      if hasattr(type(t), _TPU_EMBEDDING_ATTR):
         self._handle_tpu_embedding(t)
       # Special case 2: handle slot variables. The object_map is populated later
       # when the variable values are being copied to host CPU for the first
@@ -414,9 +414,9 @@ def _handle_tpu_embedding(self, tpu_embedding):
     Raises:
       AttributeError: if the input trackable is not TPUEmbedding type.
     """
-    if not hasattr(
-        tpu_embedding, _TPU_EMBEDDING_ATTR
-    ) or not callable(tpu_embedding._create_copy_for_async_checkpoint):  # pylint: disable=protected-access
+    if not hasattr(type(tpu_embedding), _TPU_EMBEDDING_ATTR) or not callable(
+        tpu_embedding._create_copy_for_async_checkpoint  # pylint: disable=protected-access
+    ):
       raise AttributeError(
           "Expecting TPUEmbedding type; got %s" % type(tpu_embedding)
       )