blob: 3037abfed780b8c208d1554bc3d51d369345a3ea [file] [log] [blame]
"""Updates all source files to import the same set of __future__ directives.
from lib2to3 import fixer_base
from lib2to3 import pytree
from lib2to3.pgen2 import token
from lib2to3.fixer_util import FromImport, Name, Comma, Newline
# copied from
def is_docstring(stmt):
return isinstance(stmt, pytree.Node) and \
stmt.children[0].type == token.STRING
class FixFutureImports(fixer_base.BaseFix):
BM_compatible = True
PATTERN = """import_from< 'from' module_name="__future__" 'import' any >"""
def start_tree(self, tree, filename):
self.found_future_import = False
def new_future_import(self, old):
new = FromImport("__future__",
[Name("absolute_import", prefix=" "), Comma(),
Name("division", prefix=" "), Comma(),
Name("with_statement", prefix=" ")])
if old is not None:
new.prefix = old.prefix
return new
def transform(self, node, results):
self.found_future_import = True
return self.new_future_import(node)
def finish_tree(self, tree, filename):
if self.found_future_import:
if not isinstance(tree, pytree.Node):
# Empty files (usually show up as a single Leaf
# instead of a Node, so leave them alone
first_stmt = tree.children[0]
if is_docstring(first_stmt):
# Skip a line and add the import after the docstring
tree.insert_child(1, Newline())
pos = 2
elif first_stmt.prefix:
# No docstring, but an initial comment (perhaps a #! line).
# Transfer the initial comment to a new blank line.
newline = Newline()
newline.prefix = first_stmt.prefix
first_stmt.prefix = ""
tree.insert_child(0, newline)
pos = 1
# No comments or docstring, just insert at the start
pos = 0
tree.insert_child(pos, self.new_future_import(None))
tree.insert_child(pos+1, Newline()) # terminates the import stmt