Add a warning message which happens when contrib is imported.

PiperOrigin-RevId: 225933307

tensorflow/api_template_v1.__init__.py

@@ -40,7 +40,15 @@ if not hasattr(_current_module, 'estimator'):
           'tensorflow_estimator.python.estimator.api.estimator'))
 
 from tensorflow.python.util.lazy_loader import LazyLoader  # pylint: disable=g-import-not-at-top
-contrib = LazyLoader('contrib', globals(), 'tensorflow.contrib')
+_CONTRIB_WARNING = """
+WARNING: The TensorFlow contrib module will not be included in TensorFlow 2.0.
+For more information, please see:
+  * https://github.com/tensorflow/community/blob/master/rfcs/20180907-contrib-sunset.md
+  * https://github.com/tensorflow/addons
+If you depend on functionality not listed there, please file an issue.
+"""
+contrib = LazyLoader('contrib', globals(), 'tensorflow.contrib',
+                     _CONTRIB_WARNING)
 del LazyLoader
 # The templated code that replaces the placeholder above sometimes
 # sets the __all__ variable. If it does, we have to be sure to add

tensorflow/python/util/lazy_loader.py

@@ -31,17 +31,25 @@ class LazyLoader(types.ModuleType):
   """
 
   # The lint error here is incorrect.
-  def __init__(self, local_name, parent_module_globals, name):  # pylint: disable=super-on-old-class
+  def __init__(self, local_name, parent_module_globals, name, warning=None):  # pylint: disable=super-on-old-class
     self._local_name = local_name
     self._parent_module_globals = parent_module_globals
+    self._warning = warning
 
     super(LazyLoader, self).__init__(name)
 
   def _load(self):
+    """Load the module and insert it into the parent's globals."""
     # Import the target module and insert it into the parent's namespace
     module = importlib.import_module(self.__name__)
     self._parent_module_globals[self._local_name] = module
 
+    # Emit a warning if one was specified
+    if self._warning:
+      print(self._warning)
+      # Make sure to only warn once.
+      self._warning = None
+
     # Update this object's dict so that if someone keeps a reference to the
     #   LazyLoader, lookups are efficient (__getattr__ is only called on lookups
     #   that fail).