"""Fixer for import statements. If spam is being imported from the local directory, this import: from spam import eggs Becomes: from .spam import eggs And this import: import spam Becomes: from . import spam """ # Local imports from .. import fixer_base from os.path import dirname, join, exists, sep from ..fixer_util import FromImport, syms, token def traverse_imports(names): """ Walks over all the names imported in a dotted_as_names node. """ pending = [names] while pending: node = pending.pop() if node.type == token.NAME: yield node.value elif node.type == syms.dotted_name: yield "".join([ch.value for ch in node.children]) elif node.type == syms.dotted_as_name: pending.append(node.children[0]) elif node.type == syms.dotted_as_names: pending.extend(node.children[::-2]) else: raise AssertionError("unkown node type") class FixImport(fixer_base.BaseFix): BM_compatible = True PATTERN = """ import_from< 'from' imp=any 'import' ['('] any [')'] > | import_name< 'import' imp=any > """ def start_tree(self, tree, name): super(FixImport, self).start_tree(tree, name) self.skip = "absolute_import" in tree.future_features def transform(self, node, results): if self.skip: return imp = results['imp'] if node.type == syms.import_from: # Some imps are top-level (eg: 'import ham') # some are first level (eg: 'import ham.eggs') # some are third level (eg: 'import ham.eggs as spam') # Hence, the loop while not hasattr(imp, 'value'): imp = imp.children[0] if self.probably_a_local_import(imp.value): imp.value = u"." + imp.value imp.changed() else: have_local = False have_absolute = False for mod_name in traverse_imports(imp): if self.probably_a_local_import(mod_name): have_local = True else: have_absolute = True if have_absolute: if have_local: # We won't handle both sibling and absolute imports in the # same statement at the moment. self.warning(node, "absolute and local imports together") return new = FromImport(u".", [imp]) new.prefix = node.prefix return new def probably_a_local_import(self, imp_name): if imp_name.startswith(u"."): # Relative imports are certainly not local imports. return False imp_name = imp_name.split(u".", 1)[0] base_path = dirname(self.filename) base_path = join(base_path, imp_name) # If there is no __init__.py next to the file its not in a package # so can't be a relative import. if not exists(join(dirname(base_path), "__init__.py")): return False for ext in [".py", sep, ".pyc", ".so", ".sl", ".pyd"]: if exists(base_path + ext): return True return False