Improve the error message if a non-hashable Python object that is not supported by tf.nest (such as a set) is passed to a tf.function.

PiperOrigin-RevId: 307085105
Change-Id: I044debafd1eeb509c189cf2160c2deb2221a2228

Author: edloper

tensorflow/python/eager/function.py

@@ -113,6 +113,16 @@ def _make_input_signature_hashable(elem, variable_map=None):
   except TypeError:
     assert isinstance(elem, weakref.ReferenceType)
     v = elem()
+
+    # Check if v is a Variable.  Note that we can't use isinstance to check if
+    # it's a variable, since not all variable types are subclass of Variable.
+    # TODO(mdan) Update this to use a generic "Variable" superclass once we
+    # create one.
+    if not (hasattr(v, "shape") and hasattr(v, "dtype")):
+      raise ValueError("Arguments to a tf.function must be Tensors, Variables, "
+                       "or hashable Python objects (or nested structures of "
+                       "these types).\nGot type: %s" % type(v).__name__)
+
     idx = variable_map.get(id(v))
     if idx is None:
       idx = len(variable_map)

tensorflow/python/eager/function_test.py

@@ -442,7 +442,7 @@ def testNoHash(self):
     def f(_):
       return 1.0
 
-    with self.assertRaisesRegexp(AttributeError, 'set'):
+    with self.assertRaisesRegexp(ValueError, r'Got type: set'):
       f(set([]))
 
   def testFuncName(self):