lib-python.2.7.lib2to3.fixes.fix_import.py Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jython-standalone Show documentation

Jython is an implementation of the high-level, dynamic, object-oriented language Python written in 100% Pure Java, and seamlessly integrated with the Java platform. It thus allows you to run Python on any Java platform.

The newest version!

"""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