message: Add a warning and guidance about the use of pdb.set_trace in AutoGraph code.
diff: @@ -29,6 +29,7 @@ from tensorflow.python.autograph.pyct import anno
  from tensorflow.python.autograph.pyct import ast_util
  from tensorflow.python.autograph.pyct import parser
  from tensorflow.python.autograph.pyct import templates
  +from tensorflow.python.autograph.utils import ag_logging
  # TODO(mdan): Rename to FunctionCallsTransformer.
  @@ -39,6 +40,9 @@ class _Function(object):
  no_root = True
  +set_trace_warned = False
  +
  +
  class CallTreeTransformer(converter.Base):
  """Transforms the call tree by renaming transformed symbols."""
  @@ -85,7 +89,17 @@ class CallTreeTransformer(converter.Base):
  # the normal mechanisms to bypass these literals because they are sensitive
  # to the frame they are being called from.
  # TODO(mdan): Generalize this to a "static whitelist" config.
  - if full_name in ('pdb.set_trace', 'ipdb.set_trace'):
  + if full_name in ('pdb.set_trace', 'ipdb.set_trace', 'breakpoint'):
  + global set_trace_warned
  + if not set_trace_warned:
  + # TODO(mdan): Update and shorten once available on tensorflow.org.
  + ag_logging.warn(
  + 'Detected `pdb.set_trace()` in converted code. The code'
  + ' generated by AutoGraph is not optimized for step-by-step'
  + ' debugging. See https://github.com/tensorflow/tensorflow/'
  + 'blob/master/tensorflow/python/autograph/g3doc/reference/'
  + 'debugging.md.')
  + set_trace_warned = True
  return node
  if (full_name == 'print' and
  