250 lines
12 KiB
Python
250 lines
12 KiB
Python
import warnings
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from collections import OrderedDict
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from django.apps import apps
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from django.core.management.base import BaseCommand, CommandError
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from django.core import serializers
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from django.db import router, DEFAULT_DB_ALIAS
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from django.utils.deprecation import RemovedInDjango19Warning
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class Command(BaseCommand):
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help = ("Output the contents of the database as a fixture of the given "
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"format (using each model's default manager unless --all is "
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"specified).")
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def add_arguments(self, parser):
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parser.add_argument('args', metavar='app_label[.ModelName]', nargs='*',
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help='Restricts dumped data to the specified app_label or app_label.ModelName.')
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parser.add_argument('--format', default='json', dest='format',
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help='Specifies the output serialization format for fixtures.')
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parser.add_argument('--indent', default=None, dest='indent', type=int,
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help='Specifies the indent level to use when pretty-printing output.')
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parser.add_argument('--database', action='store', dest='database',
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default=DEFAULT_DB_ALIAS,
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help='Nominates a specific database to dump fixtures from. '
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'Defaults to the "default" database.')
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parser.add_argument('-e', '--exclude', dest='exclude', action='append', default=[],
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help='An app_label or app_label.ModelName to exclude '
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'(use multiple --exclude to exclude multiple apps/models).')
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parser.add_argument('-n', '--natural', action='store_true', dest='use_natural_keys', default=False,
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help='Use natural keys if they are available (deprecated: use --natural-foreign instead).')
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parser.add_argument('--natural-foreign', action='store_true', dest='use_natural_foreign_keys', default=False,
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help='Use natural foreign keys if they are available.')
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parser.add_argument('--natural-primary', action='store_true', dest='use_natural_primary_keys', default=False,
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help='Use natural primary keys if they are available.')
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parser.add_argument('-a', '--all', action='store_true', dest='use_base_manager', default=False,
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help="Use Django's base manager to dump all models stored in the database, "
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"including those that would otherwise be filtered or modified by a custom manager.")
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parser.add_argument('--pks', dest='primary_keys',
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help="Only dump objects with given primary keys. "
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"Accepts a comma separated list of keys. "
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"This option will only work when you specify one model.")
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parser.add_argument('-o', '--output', default=None, dest='output',
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help='Specifies file to which the output is written.')
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def handle(self, *app_labels, **options):
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format = options.get('format')
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indent = options.get('indent')
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using = options.get('database')
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excludes = options.get('exclude')
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output = options.get('output')
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show_traceback = options.get('traceback')
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use_natural_keys = options.get('use_natural_keys')
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if use_natural_keys:
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warnings.warn("``--natural`` is deprecated; use ``--natural-foreign`` instead.",
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RemovedInDjango19Warning)
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use_natural_foreign_keys = options.get('use_natural_foreign_keys') or use_natural_keys
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use_natural_primary_keys = options.get('use_natural_primary_keys')
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use_base_manager = options.get('use_base_manager')
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pks = options.get('primary_keys')
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if pks:
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primary_keys = pks.split(',')
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else:
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primary_keys = []
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excluded_apps = set()
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excluded_models = set()
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for exclude in excludes:
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if '.' in exclude:
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try:
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model = apps.get_model(exclude)
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except LookupError:
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raise CommandError('Unknown model in excludes: %s' % exclude)
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excluded_models.add(model)
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else:
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try:
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app_config = apps.get_app_config(exclude)
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except LookupError:
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raise CommandError('Unknown app in excludes: %s' % exclude)
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excluded_apps.add(app_config)
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if len(app_labels) == 0:
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if primary_keys:
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raise CommandError("You can only use --pks option with one model")
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app_list = OrderedDict((app_config, None)
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for app_config in apps.get_app_configs()
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if app_config.models_module is not None and app_config not in excluded_apps)
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else:
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if len(app_labels) > 1 and primary_keys:
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raise CommandError("You can only use --pks option with one model")
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app_list = OrderedDict()
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for label in app_labels:
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try:
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app_label, model_label = label.split('.')
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try:
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app_config = apps.get_app_config(app_label)
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except LookupError:
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raise CommandError("Unknown application: %s" % app_label)
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if app_config.models_module is None or app_config in excluded_apps:
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continue
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try:
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model = app_config.get_model(model_label)
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except LookupError:
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raise CommandError("Unknown model: %s.%s" % (app_label, model_label))
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app_list_value = app_list.setdefault(app_config, [])
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# We may have previously seen a "all-models" request for
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# this app (no model qualifier was given). In this case
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# there is no need adding specific models to the list.
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if app_list_value is not None:
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if model not in app_list_value:
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app_list_value.append(model)
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except ValueError:
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if primary_keys:
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raise CommandError("You can only use --pks option with one model")
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# This is just an app - no model qualifier
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app_label = label
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try:
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app_config = apps.get_app_config(app_label)
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except LookupError:
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raise CommandError("Unknown application: %s" % app_label)
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if app_config.models_module is None or app_config in excluded_apps:
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continue
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app_list[app_config] = None
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# Check that the serialization format exists; this is a shortcut to
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# avoid collating all the objects and _then_ failing.
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if format not in serializers.get_public_serializer_formats():
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try:
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serializers.get_serializer(format)
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except serializers.SerializerDoesNotExist:
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pass
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raise CommandError("Unknown serialization format: %s" % format)
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def get_objects():
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# Collate the objects to be serialized.
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for model in sort_dependencies(app_list.items()):
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if model in excluded_models:
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continue
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if not model._meta.proxy and router.allow_migrate(using, model):
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if use_base_manager:
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objects = model._base_manager
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else:
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objects = model._default_manager
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queryset = objects.using(using).order_by(model._meta.pk.name)
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if primary_keys:
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queryset = queryset.filter(pk__in=primary_keys)
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for obj in queryset.iterator():
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yield obj
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try:
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self.stdout.ending = None
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stream = open(output, 'w') if output else None
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try:
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serializers.serialize(format, get_objects(), indent=indent,
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use_natural_foreign_keys=use_natural_foreign_keys,
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use_natural_primary_keys=use_natural_primary_keys,
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stream=stream or self.stdout)
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finally:
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if stream:
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stream.close()
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except Exception as e:
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if show_traceback:
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raise
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raise CommandError("Unable to serialize database: %s" % e)
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def sort_dependencies(app_list):
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"""Sort a list of (app_config, models) pairs into a single list of models.
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The single list of models is sorted so that any model with a natural key
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is serialized before a normal model, and any model with a natural key
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dependency has it's dependencies serialized first.
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"""
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# Process the list of models, and get the list of dependencies
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model_dependencies = []
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models = set()
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for app_config, model_list in app_list:
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if model_list is None:
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model_list = app_config.get_models()
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for model in model_list:
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models.add(model)
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# Add any explicitly defined dependencies
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if hasattr(model, 'natural_key'):
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deps = getattr(model.natural_key, 'dependencies', [])
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if deps:
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deps = [apps.get_model(dep) for dep in deps]
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else:
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deps = []
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# Now add a dependency for any FK relation with a model that
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# defines a natural key
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for field in model._meta.fields:
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if hasattr(field.rel, 'to'):
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rel_model = field.rel.to
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if hasattr(rel_model, 'natural_key') and rel_model != model:
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deps.append(rel_model)
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# Also add a dependency for any simple M2M relation with a model
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# that defines a natural key. M2M relations with explicit through
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# models don't count as dependencies.
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for field in model._meta.many_to_many:
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if field.rel.through._meta.auto_created:
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rel_model = field.rel.to
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if hasattr(rel_model, 'natural_key') and rel_model != model:
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deps.append(rel_model)
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model_dependencies.append((model, deps))
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model_dependencies.reverse()
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# Now sort the models to ensure that dependencies are met. This
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# is done by repeatedly iterating over the input list of models.
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# If all the dependencies of a given model are in the final list,
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# that model is promoted to the end of the final list. This process
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# continues until the input list is empty, or we do a full iteration
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# over the input models without promoting a model to the final list.
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# If we do a full iteration without a promotion, that means there are
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# circular dependencies in the list.
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model_list = []
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while model_dependencies:
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skipped = []
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changed = False
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while model_dependencies:
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model, deps = model_dependencies.pop()
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# If all of the models in the dependency list are either already
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# on the final model list, or not on the original serialization list,
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# then we've found another model with all it's dependencies satisfied.
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found = True
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for candidate in ((d not in models or d in model_list) for d in deps):
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if not candidate:
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found = False
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if found:
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model_list.append(model)
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changed = True
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else:
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skipped.append((model, deps))
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if not changed:
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raise CommandError("Can't resolve dependencies for %s in serialized app list." %
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', '.join('%s.%s' % (model._meta.app_label, model._meta.object_name)
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for model, deps in sorted(skipped, key=lambda obj: obj[0].__name__))
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)
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model_dependencies = skipped
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return model_list
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