Preserve __future__ imports throughout the conversion process.

PiperOrigin-RevId: 239095963

tensorflow/python/autograph/converters/directives_test.py

@@ -84,7 +84,7 @@ class DirectivesTest(converter_testing.TestCase):
     def call_invalid_directive():
       invalid_directive(1)
 
-    node, _, _ = parser.parse_entity(call_invalid_directive)
+    node, _, _ = parser.parse_entity(call_invalid_directive, future_imports=())
     # Find the call to the invalid directive
     node = node.body[0].value
     with self.assertRaisesRegexp(ValueError, 'Unexpected keyword.*'):

tensorflow/python/autograph/core/converter_testing.py

@@ -122,7 +122,7 @@ class TestCase(test.TestCase):
   def prepare(self, test_fn, namespace, arg_types=None, recursive=True):
     namespace['ConversionOptions'] = converter.ConversionOptions
 
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     namer = naming.Namer(namespace)
     program_ctx = converter.ProgramContext(
         options=converter.ConversionOptions(recursive=recursive),

tensorflow/python/autograph/impl/conversion.py

@@ -235,6 +235,21 @@ def class_to_graph(c, program_ctx):
   if not members:
     raise ValueError('Cannot convert %s: it has no member methods.' % c)
 
+  # TODO(mdan): Don't clobber namespaces for each method in one class namespace.
+  # The assumption that one namespace suffices for all methods only holds if
+  # all methods were defined in the same module.
+  # If, instead, functions are imported from multiple modules and then spliced
+  # into the class, then each function has its own globals and __future__
+  # imports that need to stay separate.
+
+  # For example, C's methods could both have `global x` statements referring to
+  # mod1.x and mod2.x, but using one namespace for C would cause a conflict.
+  # from mod1 import f1
+  # from mod2 import f2
+  # class C(object):
+  #   method1 = f1
+  #   method2 = f2
+
   class_namespace = {}
   for _, m in members:
     # Only convert the members that are directly defined by the class.
@@ -250,7 +265,13 @@ def class_to_graph(c, program_ctx):
       class_namespace = namespace
     else:
       class_namespace.update(namespace)
-    converted_members[m] = nodes[0]
+    # TODO(brianklee): function_to_graph returns future import nodes and the
+    # converted function nodes. We discard all the future import nodes here
+    # which is buggy behavior, but really, the whole approach of gathering all
+    # of the converted function nodes in one place is intrinsically buggy.
+    # So this is a reminder to properly handle the future import nodes when we
+    # redo our approach to class conversion.
+    converted_members[m] = nodes[-1]
   namer = naming.Namer(class_namespace)
   class_name = namer.class_name(c.__name__)
 
@@ -335,8 +356,11 @@ def _add_self_references(namespace, autograph_module):
 def function_to_graph(f, program_ctx, arg_values, arg_types, do_rename=True):
   """Specialization of `entity_to_graph` for callable functions."""
 
-  node, source, _ = parser.parse_entity(f)
+  future_imports = inspect_utils.getfutureimports(f)
+  node, future_import_nodes, source = parser.parse_entity(
+      f, future_imports=future_imports)
   logging.log(3, 'Source code of %s:\n\n%s\n', f, source)
+  # Parsed AST should contain future imports and one function def node.
 
   # In general, the output of inspect.getsource is inexact for lambdas because
   # it uses regex matching to adjust the exact location around the line number
@@ -386,7 +410,7 @@ def function_to_graph(f, program_ctx, arg_values, arg_types, do_rename=True):
     new_name = f.__name__
     assert node.name == new_name
 
-  return [node], new_name, namespace
+  return future_import_nodes + [node], new_name, namespace
 
 
 def node_to_graph(node, context):

tensorflow/python/autograph/impl/conversion_test.py

@@ -58,7 +58,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, ns = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.FunctionDef)
     self.assertEqual('tf__f', name)
     self.assertIs(ns['b'], b)
@@ -71,7 +71,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, _ = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.FunctionDef)
     self.assertEqual('tf__f', name)
     self.assertEqual(
@@ -87,7 +87,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, _, _ = conversion.entity_to_graph(f, program_ctx, None, None)
-    f_node = nodes[0]
+    f_node = nodes[-2]
     self.assertEqual('tf__f', f_node.name)
 
   def test_entity_to_graph_class_hierarchy(self):
@@ -144,7 +144,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, ns = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.Assign)
     self.assertIsInstance(fn_node.value, gast.Lambda)
     self.assertEqual('tf__lambda', name)
@@ -156,7 +156,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, ns = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.Assign)
     self.assertIsInstance(fn_node.value, gast.Lambda)
     self.assertEqual('tf__lambda', name)
@@ -179,7 +179,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, _ = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.Assign)
     self.assertIsInstance(fn_node.value, gast.Lambda)
     self.assertEqual('tf__lambda', name)
@@ -194,7 +194,7 @@ class ConversionTest(test.TestCase):
 
     program_ctx = self._simple_program_ctx()
     nodes, name, ns = conversion.entity_to_graph(f, program_ctx, None, None)
-    fn_node, _ = nodes
+    fn_node = nodes[-2]
     self.assertIsInstance(fn_node, gast.FunctionDef)
     self.assertEqual(fn_node.name, 'tf__f')
     self.assertEqual('tf__f', name)

tensorflow/python/autograph/pyct/cfg_test.py

@@ -40,7 +40,7 @@ class CountingVisitor(cfg.GraphVisitor):
 class GraphVisitorTest(test.TestCase):
 
   def _build_cfg(self, fn):
-    node, _, _ = parser.parse_entity(fn)
+    node, _, _ = parser.parse_entity(fn, future_imports=())
     cfgs = cfg.build(node)
     return cfgs, node
 
@@ -91,7 +91,7 @@ class GraphVisitorTest(test.TestCase):
 class AstToCfgTest(test.TestCase):
 
   def _build_cfg(self, fn):
-    node, _, _ = parser.parse_entity(fn)
+    node, _, _ = parser.parse_entity(fn, future_imports=())
     cfgs = cfg.build(node)
     return cfgs
 

tensorflow/python/autograph/pyct/common_transformers/anf_test.py

@@ -81,7 +81,7 @@ class AnfTransformerTest(test.TestCase):
     def test_function():
       a = 0
       return a
-    node, _, _ = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     node = anf.transform(node, self._simple_context())
     result, _ = compiler.ast_to_object(node)
     self.assertEqual(test_function(), result.test_function())
@@ -97,8 +97,8 @@ class AnfTransformerTest(test.TestCase):
     # Testing the code bodies only.  Wrapping them in functions so the
     # syntax highlights nicely, but Python doesn't try to execute the
     # statements.
-    exp_node, _, _ = parser.parse_entity(expected_fn)
-    node, _, _ = parser.parse_entity(test_fn)
+    exp_node, _, _ = parser.parse_entity(expected_fn, future_imports=())
+    node, _, _ = parser.parse_entity(test_fn, future_imports=())
     node = anf.transform(
         node, self._simple_context(), gensym_source=DummyGensym)
     exp_name = exp_node.name

tensorflow/python/autograph/pyct/compiler_test.py

@@ -39,12 +39,12 @@ class CompilerTest(test.TestCase):
         b = x + 1
       return b
 
-    _, _, all_nodes = parser.parse_entity(test_fn)
+    node, _, _ = parser.parse_entity(test_fn, future_imports=())
 
     self.assertEqual(
         textwrap.dedent(tf_inspect.getsource(test_fn)),
         tf_inspect.getsource(
-            compiler.ast_to_object(all_nodes)[0].test_fn))
+            compiler.ast_to_object([node])[0].test_fn))
 
   def test_ast_to_source(self):
     node = gast.If(

tensorflow/python/autograph/pyct/origin_info_test.py

@@ -32,7 +32,7 @@ class OriginInfoTest(test.TestCase):
     def test_fn(x):
       return x + 1
 
-    node, _, _ = parser.parse_entity(test_fn)
+    node, _, _ = parser.parse_entity(test_fn, future_imports=())
     fake_origin = origin_info.OriginInfo(
         loc=origin_info.Location('fake_filename', 3, 7),
         function_name='fake_function_name',
@@ -53,7 +53,7 @@ class OriginInfoTest(test.TestCase):
     def test_fn(x):
       return x + 1
 
-    node, _, _ = parser.parse_entity(test_fn)
+    node, _, _ = parser.parse_entity(test_fn, future_imports=())
     converted_code = compiler.ast_to_source(node)
 
     source_map = origin_info.create_source_map(
@@ -67,7 +67,7 @@ class OriginInfoTest(test.TestCase):
       """Docstring."""
       return x  # comment
 
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
 
     origin_info.resolve(node, source)
 
@@ -89,14 +89,15 @@ class OriginInfoTest(test.TestCase):
     self.assertEqual(origin.source_code_line, '  return x  # comment')
     self.assertEqual(origin.comment, 'comment')
 
-  def disabled_test_resolve_with_future_imports(self):
+  def test_resolve_with_future_imports(self):
 
     def test_fn(x):
       """Docstring."""
       print(x)
       return x  # comment
 
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(
+        test_fn, future_imports=['print_function'])
 
     origin_info.resolve(node, source)
 

tensorflow/python/autograph/pyct/parser.py

@@ -21,12 +21,11 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
-import re
+import itertools
 import textwrap
 import threading
 
 import gast
-import six
 
 from tensorflow.python.util import tf_inspect
 
@@ -34,17 +33,18 @@ from tensorflow.python.util import tf_inspect
 _parse_lock = threading.Lock()  # Prevents linecache concurrency errors.
 
 
-def parse_entity(entity):
+def parse_entity(entity, future_imports):
   """Returns the AST and source code of given entity.
 
   Args:
     entity: A python function/method/class
+    future_imports: An iterable of future imports to use when parsing AST. (e.g.
+        ('print_statement', 'division', 'unicode_literals'))
 
   Returns:
-    gast.AST, str, gast.ModuleNode: a tuple of the AST node corresponding
-    exactly to the entity; the string that was parsed to generate the AST; and
-    the containing module AST node, which might contain extras like future
-    import nodes.
+    gast.AST, List[gast.AST], str: a tuple of the AST node corresponding
+    exactly to the entity; a list of future import AST nodes, and the string
+    that was parsed to generate the AST.
   """
   try:
     with _parse_lock:
@@ -67,11 +67,13 @@ def parse_entity(entity):
   # causing textwrap.dedent to not correctly dedent source code.
   # TODO(b/115884650): Automatic handling of comments/multiline strings.
   source = textwrap.dedent(source)
+  future_import_strings = ('from __future__ import {}'.format(name)
+                           for name in future_imports)
+  source = '\n'.join(itertools.chain(future_import_strings, [source]))
 
   try:
     module_node = parse_str(source)
-    assert len(module_node.body) == 1
-    return module_node.body[0], source, module_node
+    return _select_entity_node(module_node, source, future_imports)
 
   except IndentationError:
     # The text below lists the causes of this error known to us. There may
@@ -112,7 +114,7 @@ def parse_entity(entity):
 
     try:
       module_node = parse_str(new_source)
-      return module_node.body[0], new_source, module_node
+      return _select_entity_node(module_node, new_source, future_imports)
     except SyntaxError as e:
       raise_parse_failure(
           'If this is a lambda function, the error may be avoided by creating'
@@ -122,18 +124,7 @@ def parse_entity(entity):
 
 def parse_str(src):
   """Returns the AST of given piece of code."""
-  # TODO(mdan): This should exclude the module things are autowrapped in.
-
-  if six.PY2 and re.search('\\Wprint\\s*\\(', src):
-    # This special treatment is required because gast.parse is not aware of
-    # whether print_function was present in the original context.
-    src = 'from __future__ import print_function\n' + src
-    parsed_module = gast.parse(src)
-    parsed_module.body = parsed_module.body[1:]
-  else:
-    parsed_module = gast.parse(src)
-
-  return parsed_module
+  return gast.parse(src)
 
 
 def parse_expression(src):
@@ -152,3 +143,9 @@ def parse_expression(src):
     raise ValueError(
         'Expected a single expression, found instead %s' % node.body)
   return node.body[0].value
+
+
+def _select_entity_node(module_node, source, future_imports):
+  assert len(module_node.body) == 1 + len(future_imports)
+  return module_node.body[-1], module_node.body[:-1], source
+

tensorflow/python/autograph/pyct/parser_test.py

@@ -18,8 +18,6 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
-import textwrap
-
 from tensorflow.python.autograph.pyct import parser
 from tensorflow.python.platform import test
 
@@ -31,41 +29,22 @@ class ParserTest(test.TestCase):
     def f(x):
       return x + 1
 
-    node, _, _ = parser.parse_entity(f)
+    node, _, _ = parser.parse_entity(f, future_imports=())
     self.assertEqual('f', node.name)
 
-  def test_parse_str(self):
-    mod = parser.parse_str(
-        textwrap.dedent("""
-            def f(x):
-              return x + 1
-    """))
-    self.assertEqual('f', mod.body[0].name)
-
-  def test_parse_str_print(self):
-    mod = parser.parse_str(
-        textwrap.dedent("""
-            def f(x):
-              print(x)
-              return x + 1
-    """))
-    self.assertEqual('f', mod.body[0].name)
-
-  def test_parse_str_weird_print(self):
-    mod = parser.parse_str(
-        textwrap.dedent("""
-            def f(x):
-              print (x)
-              return x + 1
-    """))
-    self.assertEqual('f', mod.body[0].name)
+  def test_parse_entity_print_function(self):
+    def f(x):
+      print(x)
+    node, _, _ = parser.parse_entity(
+        f, future_imports=['print_function'])
+    self.assertEqual('f', node.name)
 
   def test_parse_comments(self):
     def f():
 # unindented comment
       pass
     with self.assertRaises(ValueError):
-      parser.parse_entity(f)
+      parser.parse_entity(f, future_imports=())
 
   def test_parse_multiline_strings(self):
     def f():
@@ -74,7 +53,7 @@ some
 multiline
 string""")
     with self.assertRaises(ValueError):
-      parser.parse_entity(f)
+      parser.parse_entity(f, future_imports=())
 
   def test_parse_expression(self):
     node = parser.parse_expression('a.b')

tensorflow/python/autograph/pyct/static_analysis/activity_test.py

@@ -112,7 +112,7 @@ class ScopeTest(test.TestCase):
 class ActivityAnalyzerTest(test.TestCase):
 
   def _parse_and_analyze(self, test_fn):
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     entity_info = transformer.EntityInfo(
         source_code=source,
         source_file=None,

tensorflow/python/autograph/pyct/static_analysis/live_values_test.py

@@ -41,7 +41,7 @@ class LiveValuesResolverTest(test.TestCase):
                          literals=None,
                          arg_types=None):
     literals = literals or {}
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     entity_info = transformer.EntityInfo(
         source_code=source,
         source_file=None,

tensorflow/python/autograph/pyct/static_analysis/liveness_test.py

@@ -33,7 +33,7 @@ from tensorflow.python.platform import test
 class LivenessTest(test.TestCase):
 
   def _parse_and_analyze(self, test_fn):
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     entity_info = transformer.EntityInfo(
         source_code=source,
         source_file=None,

tensorflow/python/autograph/pyct/static_analysis/reaching_definitions_test.py

@@ -33,7 +33,7 @@ from tensorflow.python.platform import test
 class DefinitionInfoTest(test.TestCase):
 
   def _parse_and_analyze(self, test_fn):
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     entity_info = transformer.EntityInfo(
         source_code=source,
         source_file=None,

tensorflow/python/autograph/pyct/static_analysis/type_info_test.py

@@ -62,7 +62,7 @@ class TypeInfoResolverTest(test.TestCase):
                          test_fn,
                          namespace,
                          arg_types=None):
-    node, source, _ = parser.parse_entity(test_fn)
+    node, _, source = parser.parse_entity(test_fn, future_imports=())
     entity_info = transformer.EntityInfo(
         source_code=source,
         source_file=None,

tensorflow/python/autograph/pyct/transformer_test.py

@@ -68,7 +68,7 @@ class TransformerTest(test.TestCase):
           return b, inner_function
       return a, TestClass
 
-    node, _, _ = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     node = tr.visit(node)
 
     test_function_node = node
@@ -141,7 +141,7 @@ class TransformerTest(test.TestCase):
           while True:
             raise '1'
 
-    node, _, _ = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     node = tr.visit(node)
 
     fn_body = node.body
@@ -207,7 +207,7 @@ class TransformerTest(test.TestCase):
             raise '1'
       return 'nor this'
 
-    node, _, _ = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     node = tr.visit(node)
 
     for_node = node.body[2]
@@ -238,7 +238,7 @@ class TransformerTest(test.TestCase):
         print(a)
       return None
 
-    node, _, _ = parser.parse_entity(no_exit)
+    node, _, _ = parser.parse_entity(no_exit, future_imports=())
     with self.assertRaises(AssertionError):
       tr.visit(node)
 
@@ -246,7 +246,7 @@ class TransformerTest(test.TestCase):
       for _ in a:
         print(a)
 
-    node, _, _ = parser.parse_entity(no_entry)
+    node, _, _ = parser.parse_entity(no_entry, future_imports=())
     with self.assertRaises(AssertionError):
       tr.visit(node)
 
@@ -272,7 +272,7 @@ class TransformerTest(test.TestCase):
 
     tr = TestTransformer(self._simple_context())
 
-    node, _, _ = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     node = tr.visit(node)
 
     self.assertEqual(len(node.body), 2)
@@ -302,9 +302,9 @@ class TransformerTest(test.TestCase):
 
     tr = BrokenTransformer(self._simple_context())
 
-    _, _, all_nodes = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     with self.assertRaises(ValueError) as cm:
-      all_nodes = tr.visit(all_nodes)
+      node = tr.visit(node)
     obtained_message = str(cm.exception)
     expected_message = r'expected "ast.AST", got "\<(type|class) \'list\'\>"'
     self.assertRegexpMatches(obtained_message, expected_message)
@@ -333,9 +333,9 @@ class TransformerTest(test.TestCase):
 
     tr = BrokenTransformer(self._simple_context())
 
-    _, _, all_nodes = parser.parse_entity(test_function)
+    node, _, _ = parser.parse_entity(test_function, future_imports=())
     with self.assertRaises(ValueError) as cm:
-      all_nodes = tr.visit(all_nodes)
+      node = tr.visit(node)
     obtained_message = str(cm.exception)
     # The message should reference the exception actually raised, not anything
     # from the exception handler.