Commit b9c619ab authored by Aymeric Augustin's avatar Aymeric Augustin
Browse files

Prevented makemigrations from writing in sys.path[0]. 

There's no reason to assume that sys.path[0] is an appropriate location
for generating code. Specifically that doesn't work with extend_sys_path
which puts the additional directories at the end of sys.path.

In order to create a new migrations module, instead of using an
arbitrary entry from sys.path, import as much as possible from the path
to the module, then create missing submodules from there.

Without this change, the tests introduced in the following commit fail,
which seems sufficient to prevent regressions for such a refactoring.
parent 952ce778

django/db/migrations/writer.py

+54 −31
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ import inspect 
import math

import os

import re

import sys

import types

from importlib import import_module
@@ -18,6 +17,7 @@ from django.utils import datetime_safe, six 
from django.utils._os import upath

from django.utils.encoding import force_text

from django.utils.functional import Promise

from django.utils.module_loading import module_dir

from django.utils.timezone import utc

from django.utils.version import get_docs_version
@@ -201,43 +201,66 @@ class MigrationWriter(object): 
        return value_repr



    @property

    def filename(self):

        return "%s.py" % self.migration.name



    @property

    def path(self):

    def basedir(self):

        migrations_package_name = MigrationLoader.migrations_module(self.migration.app_label)



        # See if we can import the migrations module directly

        try:

            migrations_module = import_module(migrations_package_name)



            # Python 3 fails when the migrations directory does not have a

            # __init__.py file

            if not hasattr(migrations_module, '__file__'):

                raise ImportError



            basedir = os.path.dirname(upath(migrations_module.__file__))

        except ImportError:

            app_config = apps.get_app_config(self.migration.app_label)

            migrations_package_basename = migrations_package_name.split(".")[-1]

            pass

        else:

            try:

                return upath(module_dir(migrations_module))

            except ValueError:

                pass



        # Alright, see if it's a direct submodule of the app

            if '%s.%s' % (app_config.name, migrations_package_basename) == migrations_package_name:

                basedir = os.path.join(app_config.path, migrations_package_basename)

        app_config = apps.get_app_config(self.migration.app_label)

        maybe_app_name, _, migrations_package_basename = migrations_package_name.rpartition(".")

        if app_config.name == maybe_app_name:

            return os.path.join(app_config.path, migrations_package_basename)



        # In case of using MIGRATION_MODULES setting and the custom package

        # doesn't exist, create one, starting from an existing package

        existing_dirs, missing_dirs = migrations_package_name.split("."), []

        while existing_dirs:

            missing_dirs.insert(0, existing_dirs.pop(-1))

            try:

                base_module = import_module(".".join(existing_dirs))

            except ImportError:

                continue

            else:

                # In case of using MIGRATION_MODULES setting and the custom

                # package doesn't exist, create one.

                package_dirs = migrations_package_name.split(".")

                create_path = os.path.join(upath(sys.path[0]), *package_dirs)

                if not os.path.isdir(create_path):

                    os.makedirs(create_path)

                for i in range(1, len(package_dirs) + 1):

                    init_dir = os.path.join(upath(sys.path[0]), *package_dirs[:i])

                    init_path = os.path.join(init_dir, "__init__.py")

                    if not os.path.isfile(init_path):

                        open(init_path, "w").close()

                return os.path.join(create_path, self.filename)

        return os.path.join(basedir, self.filename)

                try:

                    base_dir = upath(module_dir(base_module))

                except ValueError:

                    continue

                else:

                    break

        else:

            raise ValueError(

                "Could not locate an appropriate location to create "

                "migrations package %s. Make sure the toplevel "

                "package exists and can be imported." %

                migrations_package_name)



        final_dir = os.path.join(base_dir, *missing_dirs)

        if not os.path.isdir(final_dir):

            os.makedirs(final_dir)

        for missing_dir in missing_dirs:

            base_dir = os.path.join(base_dir, missing_dir)

            with open(os.path.join(base_dir, "__init__.py"), "w"):

                pass



        return final_dir



    @property

    def filename(self):

        return "%s.py" % self.migration.name



    @property

    def path(self):

        return os.path.join(self.basedir, self.filename)



    @classmethod

    def serialize_deconstructed(cls, path, args, kwargs):

django/utils/module_loading.py

+18 −0
Original line number Diff line number Diff line
@@ -148,3 +148,21 @@ else: 
        else:

            # Exhausted the search, so the module cannot be found.

            return False





def module_dir(module):

    """

    Find the name of the directory that contains a module, if possible.



    Raise ValueError otherwise, e.g. for namespace packages that are split

    over several directories.

    """

    # Convert to list because _NamespacePath does not support indexing on 3.3.

    paths = list(getattr(module, '__path__', []))

    if len(paths) == 1:

        return paths[0]

    else:

        filename = getattr(module, '__file__', None)

        if filename is not None:

            return os.path.dirname(filename)

    raise ValueError("Cannot determine directory containing %s" % module)