Account for the possibility of closing over an undefined variable when getting a function's namespace.

PiperOrigin-RevId: 293210304
Change-Id: Ia16c9032c63a38106a38ba2039c274c4752a0b64

tensorflow/python/autograph/pyct/inspect_utils.py

@@ -166,7 +166,11 @@ def getnamespace(f):
   freevars = six.get_function_code(f).co_freevars
   if freevars and closure:
     for name, cell in zip(freevars, closure):
-      namespace[name] = cell.cell_contents
+      try:
+        namespace[name] = cell.cell_contents
+      except ValueError:
+        # Cell contains undefined variable, omit it from the namespace.
+        pass
   return namespace
 
 

tensorflow/python/autograph/pyct/inspect_utils_test.py

@@ -253,6 +253,21 @@ class InspectUtilsTest(test.TestCase):
     ns = inspect_utils.getnamespace(factory)
     self.assertEqual(ns['free_function'], free_function)
 
+  def test_getnamespace_closure_with_undefined_var(self):
+    if False:  # pylint:disable=using-constant-test
+      a = 1
+
+    def test_fn():
+      return a
+
+    ns = inspect_utils.getnamespace(test_fn)
+    self.assertNotIn('a', ns)
+
+    a = 2
+    ns = inspect_utils.getnamespace(test_fn)
+
+    self.assertEqual(ns['a'], 2)
+
   def test_getnamespace_hermetic(self):
 
     # Intentionally hiding the global function to make sure we don't overwrite