"""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):
PATTERN = """
import_from< 'from' imp=any 'import' ['('] any [')'] >
|
import_name< 'import' imp=any >
"""
def transform(self, node, results):
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 = "." + 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('.', [imp])
new.prefix = node.prefix
return new
def probably_a_local_import(self, imp_name):
imp_name = imp_name.split('.', 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
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