def _generate_removed_field(self, app_label, model_name, field_name):
field = get_model_state_field(
self.from_state.models[app_label, model_name], field_name
)
remove_default = field.default
if remove_default is NOT_PROVIDED and field.null:
return super()._generate_removed_field(app_label, model_name, field_name)
if remove_default is NOT_PROVIDED:
if self.has_interactive_questionner:
choice = self.questioner._choice_input(
"You are trying to remove a non-nullable field '%s' from %s without a default; "
"we can't do that (the database needs a default for inserts before the removal).\n"
"Please select a fix:" % (field_name, model_name),
[
(
"Provide a one-off default now (will be set at the "
"database level in pre-deployment stage)"
),
(
"Make the field temporarily nullable (attempts at reverting the "
"field removal might fail)"
),
],
)
if choice == 1:
remove_default = self.questioner._ask_default()
elif choice == 2:
pass
else:
sys.exit(3)
else:
remove_default = self.questioner.defaults.get("ask_remove_default")
if remove_default is not NOT_PROVIDED:
field = field.clone()
field.default = remove_default
pre_remove_field = PreRemoveField(
model_name=model_name, name=field_name, field=field
)
self.add_operation(app_label, pre_remove_field)
stage = OperationStage()
self.add_operation(
self.STAGE_SPLIT,
stage,
dependencies=[
(app_label, self.STAGE_SPLIT, self.generated_operations[app_label][-1])
],
)
self.add_operation(
app_label,
operations.RemoveField(model_name=model_name, name=field_name),
dependencies=[
(app_label, model_name, field_name, "order_wrt_unset"),
(app_label, model_name, field_name, "foo_together_change"),
(self.STAGE_SPLIT, stage),
],
)
def test_operation_is_safe(self):
assert migration_utils.operation_is_safe(
operations.AddField(
model_name="unsafemodel",
name="safe_field",
field=models.IntegerField(null=True),
)
)
assert (
migration_utils.operation_is_safe(
operations.AddField(
model_name="unsafemodel",
name="field_added",
field=models.IntegerField(default=1),
preserve_default=False,
)
)
is False
)
assert (
migration_utils.operation_is_safe(
operations.AlterField(
model_name="unsafemodel",
name="field_added",
field=models.PositiveIntegerField(default=10),
preserve_default=False,
)
)
is False
)
assert (
migration_utils.operation_is_safe(
operations.RenameField(
model_name="unsafemodel", old_name="field_added", new_name="field_renamed"
)
)
is False
)
assert (
migration_utils.operation_is_safe(
operations.RemoveField(
model_name="unsafemodel",
name="field_renamed",
)
)
is False
)
assert migration_utils.operation_is_safe(operations.DeleteModel("unsafemodel")) is False
assert migration_utils.operation_is_safe(operations.RunSQL("")) is False
assert migration_utils.operation_is_safe(operations.RunPython(lambda: True)) is False
def __init__(self, model_name, name, **kwargs):
"""
Arguments as per RemoveField (i.e., from the django migration file made for the model moved to its new app)
"""
super().__init__(
state_operations=[
operations.RemoveField(model_name=model_name, name=name, **kwargs),
],
database_operations=[]
)
def generate_removed_fields(self):
"""
Fields that have been removed.
"""
for app_label, model_name, field_name in sorted(self.old_field_keys -
self.new_field_keys):
self.add_operation(
app_label,
operations.RemoveField(
model_name=model_name,
name=field_name,
))
def generate_removed_fields(self):
"""
Fields that have been removed.
"""
for app_label, model_name, field_name in sorted(self.old_field_keys - self.new_field_keys):
self.add_operation(
app_label,
operations.RemoveField(
model_name=model_name,
name=field_name,
),
# We might need to depend on the removal of an order_with_respect_to;
# this is safely ignored if there isn't one
dependencies=[(app_label, model_name, field_name, "order_wrt_unset")],
)
def generate_deleted_models(self):
"""
Find all deleted models and make creation operations for them,
and separate operations to delete any foreign key or M2M relationships
(we'll optimise these back in later if we can)
We also bring forward removal of any model options that refer to
collections of fields - the inverse of generate_created_models.
"""
deleted_models = set(self.old_model_keys) - set(self.new_model_keys)
for app_label, model_name in sorted(deleted_models):
model_state = self.from_state.models[app_label, model_name]
model = self.old_apps.get_model(app_label, model_name)
# Gather related fields
related_fields = {}
for field in model._meta.local_fields:
if field.rel:
if field.rel.to:
related_fields[field.name] = field
if hasattr(field.rel, "through"
) and not field.rel.through._meta.auto_created:
related_fields[field.name] = field
for field in model._meta.local_many_to_many:
if field.rel.to:
related_fields[field.name] = field
if hasattr(field.rel, "through"
) and not field.rel.through._meta.auto_created:
related_fields[field.name] = field
# Generate option removal first
unique_together = model_state.options.pop('unique_together', None)
index_together = model_state.options.pop('index_together', None)
if unique_together:
self.add_operation(
app_label,
operations.AlterUniqueTogether(
name=model_name,
unique_together=None,
))
if index_together:
self.add_operation(
app_label,
operations.AlterIndexTogether(
name=model_name,
index_together=None,
))
# Then remove each related field
for name, field in sorted(related_fields.items()):
self.add_operation(
app_label,
operations.RemoveField(
model_name=model_name,
name=name,
))
# Finally, remove the model.
# This depends on both the removal of all incoming fields
# and the removal of all its own related fields, and if it's
# a through model the field that references it.
dependencies = []
for related_object in model._meta.get_all_related_objects():
dependencies.append((
related_object.model._meta.app_label,
related_object.model._meta.object_name,
related_object.field.name,
False,
))
for related_object in model._meta.get_all_related_many_to_many_objects(
):
dependencies.append((
related_object.model._meta.app_label,
related_object.model._meta.object_name,
related_object.field.name,
False,
))
for name, field in sorted(related_fields.items()):
dependencies.append((app_label, model_name, name, False))
# We're referenced in another field's through=
through_user = self.through_users.get(
(app_label, model_state.name.lower()), None)
if through_user:
dependencies.append(
(through_user[0], through_user[1], through_user[2], False))
# Finally, make the operation, deduping any dependencies
self.add_operation(
app_label,
operations.DeleteModel(name=model_state.name, ),
dependencies=list(set(dependencies)),
)
def _detect_changes(self):
"""
Returns a dict of migration plans which will achieve the
change from from_state to to_state. The dict has app labels
as keys and a list of migrations as values.
The resulting migrations aren't specially named, but the names
do matter for dependencies inside the set.
"""
# We'll store migrations as lists by app names for now
self.migrations = {}
old_app_cache = self.from_state.render()
new_app_cache = self.to_state.render()
# Prepare lists of old/new model keys that we care about
# (i.e. ignoring proxy ones)
old_model_keys = [
(al, mn)
for al, mn in self.from_state.models.keys()
if not old_app_cache.get_model(al, mn)._meta.proxy
]
new_model_keys = [
(al, mn)
for al, mn in self.to_state.models.keys()
if not new_app_cache.get_model(al, mn)._meta.proxy
]
# Adding models. Phase 1 is adding models with no outward relationships.
added_models = set(new_model_keys) - set(old_model_keys)
pending_add = {}
for app_label, model_name in added_models:
model_state = self.to_state.models[app_label, model_name]
# Are there any relationships out from this model? if so, punt it to the next phase.
related_fields = []
for field in new_app_cache.get_model(app_label, model_name)._meta.local_fields:
if field.rel:
if field.rel.to:
related_fields.append((field.name, field.rel.to._meta.app_label.lower(), field.rel.to._meta.object_name.lower()))
if hasattr(field.rel, "through") and not field.rel.though._meta.auto_created:
related_fields.append((field.name, field.rel.through._meta.app_label.lower(), field.rel.through._meta.object_name.lower()))
if related_fields:
pending_add[app_label, model_name] = related_fields
else:
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=model_state.fields,
options=model_state.options,
bases=model_state.bases,
)
)
# Phase 2 is progressively adding pending models, splitting up into two
# migrations if required.
pending_new_fks = []
while pending_add:
# Is there one we can add that has all dependencies satisfied?
satisfied = [(m, rf) for m, rf in pending_add.items() if all((al, mn) not in pending_add for f, al, mn in rf)]
if satisfied:
(app_label, model_name), related_fields = sorted(satisfied)[0]
model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=model_state.fields,
options=model_state.options,
bases=model_state.bases,
)
)
for field_name, other_app_label, other_model_name in related_fields:
if app_label != other_app_label:
self.add_dependency(app_label, other_app_label)
del pending_add[app_label, model_name]
# Ah well, we'll need to split one. Pick deterministically.
else:
(app_label, model_name), related_fields = sorted(pending_add.items())[0]
model_state = self.to_state.models[app_label, model_name]
# Work out the fields that need splitting out
bad_fields = dict((f, (al, mn)) for f, al, mn in related_fields if (al, mn) in pending_add)
# Create the model, without those
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=[(n, f) for n, f in model_state.fields if n not in bad_fields],
options=model_state.options,
bases=model_state.bases,
)
)
# Add the bad fields to be made in a phase 3
for field_name, (other_app_label, other_model_name) in bad_fields.items():
pending_new_fks.append((app_label, model_name, field_name, other_app_label))
del pending_add[app_label, model_name]
# Phase 3 is adding the final set of FKs as separate new migrations
for app_label, model_name, field_name, other_app_label in pending_new_fks:
model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=model_state.get_field_by_name(field_name),
),
new=True,
)
if app_label != other_app_label:
self.add_dependency(app_label, other_app_label)
# Removing models
removed_models = set(old_model_keys) - set(new_model_keys)
for app_label, model_name in removed_models:
model_state = self.from_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.DeleteModel(
model_state.name,
)
)
# Changes within models
kept_models = set(old_model_keys).intersection(new_model_keys)
old_fields = set()
new_fields = set()
for app_label, model_name in kept_models:
old_model_state = self.from_state.models[app_label, model_name]
new_model_state = self.to_state.models[app_label, model_name]
# Collect field changes for later global dealing with (so AddFields
# always come before AlterFields even on separate models)
old_fields.update((app_label, model_name, x) for x, y in old_model_state.fields)
new_fields.update((app_label, model_name, x) for x, y in new_model_state.fields)
# Unique_together changes
if old_model_state.options.get("unique_together", set()) != new_model_state.options.get("unique_together", set()):
self.add_to_migration(
app_label,
operations.AlterUniqueTogether(
name=model_name,
unique_together=new_model_state.options.get("unique_together", set()),
)
)
# New fields
for app_label, model_name, field_name in new_fields - old_fields:
old_model_state = self.from_state.models[app_label, model_name]
new_model_state = self.to_state.models[app_label, model_name]
field = new_model_state.get_field_by_name(field_name)
# Scan to see if this is actually a rename!
field_dec = field.deconstruct()[1:]
found_rename = False
for rem_app_label, rem_model_name, rem_field_name in (old_fields - new_fields):
if rem_app_label == app_label and rem_model_name == model_name:
if old_model_state.get_field_by_name(rem_field_name).deconstruct()[1:] == field_dec:
if self.questioner.ask_rename(model_name, rem_field_name, field_name, field):
self.add_to_migration(
app_label,
operations.RenameField(
model_name=model_name,
old_name=rem_field_name,
new_name=field_name,
)
)
old_fields.remove((rem_app_label, rem_model_name, rem_field_name))
new_fields.remove((app_label, model_name, field_name))
found_rename = True
break
if found_rename:
continue
# You can't just add NOT NULL fields with no default
if not field.null and not field.has_default():
field = field.clone()
field.default = self.questioner.ask_not_null_addition(field_name, model_name)
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=field,
preserve_default=False,
)
)
else:
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=field,
)
)
# Old fields
for app_label, model_name, field_name in old_fields - new_fields:
old_model_state = self.from_state.models[app_label, model_name]
new_model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.RemoveField(
model_name=model_name,
name=field_name,
)
)
# The same fields
for app_label, model_name, field_name in old_fields.intersection(new_fields):
# Did the field change?
old_model_state = self.from_state.models[app_label, model_name]
new_model_state = self.to_state.models[app_label, model_name]
old_field_dec = old_model_state.get_field_by_name(field_name).deconstruct()
new_field_dec = new_model_state.get_field_by_name(field_name).deconstruct()
if old_field_dec != new_field_dec:
self.add_to_migration(
app_label,
operations.AlterField(
model_name=model_name,
name=field_name,
field=new_model_state.get_field_by_name(field_name),
)
)
# Alright, now add internal dependencies
for app_label, migrations in self.migrations.items():
for m1, m2 in zip(migrations, migrations[1:]):
m2.dependencies.append((app_label, m1.name))
# Clean up dependencies
for app_label, migrations in self.migrations.items():
for migration in migrations:
migration.dependencies = list(set(migration.dependencies))
return self.migrations
def _detect_changes(self):
"""
Returns a dict of migration plans which will achieve the
change from from_state to to_state. The dict has app labels
as keys and a list of migrations as values.
The resulting migrations aren't specially named, but the names
do matter for dependencies inside the set.
"""
# We'll store migrations as lists by app names for now
self.migrations = {}
old_apps = self.from_state.render()
new_apps = self.to_state.render()
# Prepare lists of old/new model keys that we care about
# (i.e. ignoring proxy ones)
old_model_keys = [(al, mn) for al, mn in self.from_state.models.keys()
if not old_apps.get_model(al, mn)._meta.proxy]
new_model_keys = [(al, mn) for al, mn in self.to_state.models.keys()
if not new_apps.get_model(al, mn)._meta.proxy]
def _rel_agnostic_fields_def(fields):
"""
Return a definition of the fields that ignores field names and
what related fields actually relate to.
"""
fields_def = []
for name, field in fields:
deconstruction = field.deconstruct()[1:]
if field.rel and field.rel.to:
del deconstruction[2]['to']
fields_def.append(deconstruction)
return fields_def
# Find any renamed models.
renamed_models = {}
renamed_models_rel = {}
added_models = set(new_model_keys) - set(old_model_keys)
for app_label, model_name in added_models:
model_state = self.to_state.models[app_label, model_name]
model_fields_def = _rel_agnostic_fields_def(model_state.fields)
removed_models = set(old_model_keys) - set(new_model_keys)
for rem_app_label, rem_model_name in removed_models:
if rem_app_label == app_label:
rem_model_state = self.from_state.models[rem_app_label,
rem_model_name]
rem_model_fields_def = _rel_agnostic_fields_def(
rem_model_state.fields)
if model_fields_def == rem_model_fields_def:
if self.questioner.ask_rename_model(
rem_model_state, model_state):
self.add_to_migration(
app_label,
operations.RenameModel(
old_name=rem_model_state.name,
new_name=model_state.name,
))
renamed_models[app_label,
model_name] = rem_model_name
renamed_models_rel[
'%s.%s' %
(rem_model_state.app_label,
rem_model_state.name)] = '%s.%s' % (
model_state.app_label, model_state.name)
old_model_keys.remove(
(rem_app_label, rem_model_name))
old_model_keys.append((app_label, model_name))
break
# Adding models. Phase 1 is adding models with no outward relationships.
added_models = set(new_model_keys) - set(old_model_keys)
pending_add = {}
for app_label, model_name in added_models:
model_state = self.to_state.models[app_label, model_name]
# Are there any relationships out from this model? if so, punt it to the next phase.
related_fields = []
for field in new_apps.get_model(app_label,
model_name)._meta.local_fields:
if field.rel:
if field.rel.to:
related_fields.append(
(field.name, field.rel.to._meta.app_label,
field.rel.to._meta.model_name))
if hasattr(field.rel, "through"
) and not field.rel.through._meta.auto_created:
related_fields.append(
(field.name, field.rel.through._meta.app_label,
field.rel.through._meta.model_name))
for field in new_apps.get_model(
app_label, model_name)._meta.local_many_to_many:
if field.rel.to:
related_fields.append(
(field.name, field.rel.to._meta.app_label,
field.rel.to._meta.model_name))
if hasattr(field.rel, "through"
) and not field.rel.through._meta.auto_created:
related_fields.append(
(field.name, field.rel.through._meta.app_label,
field.rel.through._meta.model_name))
if related_fields:
pending_add[app_label, model_name] = related_fields
else:
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=model_state.fields,
options=model_state.options,
bases=model_state.bases,
))
# Phase 2 is progressively adding pending models, splitting up into two
# migrations if required.
pending_new_fks = []
pending_unique_together = []
added_phase_2 = set()
while pending_add:
# Is there one we can add that has all dependencies satisfied?
satisfied = [(m, rf) for m, rf in pending_add.items() if all(
(al, mn) not in pending_add for f, al, mn in rf)]
if satisfied:
(app_label, model_name), related_fields = sorted(satisfied)[0]
model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=model_state.fields,
options=model_state.options,
bases=model_state.bases,
),
# If it's already been added in phase 2 put it in a new
# migration for safety.
new=any((al, mn) in added_phase_2
for f, al, mn in related_fields),
)
for field_name, other_app_label, other_model_name in related_fields:
# If it depends on a swappable something, add a dynamic depend'cy
swappable_setting = new_apps.get_model(
app_label, model_name)._meta.get_field_by_name(
field_name)[0].swappable_setting
if swappable_setting is not None:
self.add_swappable_dependency(app_label,
swappable_setting)
elif app_label != other_app_label:
self.add_dependency(app_label, other_app_label)
del pending_add[app_label, model_name]
added_phase_2.add((app_label, model_name))
# Ah well, we'll need to split one. Pick deterministically.
else:
(app_label,
model_name), related_fields = sorted(pending_add.items())[0]
model_state = self.to_state.models[app_label, model_name]
# Defer unique together constraints creation, see ticket #22275
unique_together_constraints = model_state.options.pop(
'unique_together', None)
if unique_together_constraints:
pending_unique_together.append(
(app_label, model_name, unique_together_constraints))
# Work out the fields that need splitting out
bad_fields = dict((f, (al, mn)) for f, al, mn in related_fields
if (al, mn) in pending_add)
# Create the model, without those
self.add_to_migration(
app_label,
operations.CreateModel(
name=model_state.name,
fields=[(n, f) for n, f in model_state.fields
if n not in bad_fields],
options=model_state.options,
bases=model_state.bases,
))
# Add the bad fields to be made in a phase 3
for field_name, (other_app_label,
other_model_name) in bad_fields.items():
pending_new_fks.append(
(app_label, model_name, field_name, other_app_label))
del pending_add[app_label, model_name]
# Phase 3 is adding the final set of FKs as separate new migrations
for app_label, model_name, field_name, other_app_label in pending_new_fks:
model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=model_state.get_field_by_name(field_name),
),
new=True,
)
# If it depends on a swappable something, add a dynamic depend'cy
swappable_setting = new_apps.get_model(
app_label, model_name)._meta.get_field_by_name(
field_name)[0].swappable_setting
if swappable_setting is not None:
self.add_swappable_dependency(app_label, swappable_setting)
elif app_label != other_app_label:
self.add_dependency(app_label, other_app_label)
# Phase 3.1 - unique together constraints
for app_label, model_name, unique_together in pending_unique_together:
self.add_to_migration(
app_label,
operations.AlterUniqueTogether(
name=model_name, unique_together=unique_together))
# Removing models
removed_models = set(old_model_keys) - set(new_model_keys)
for app_label, model_name in removed_models:
model_state = self.from_state.models[app_label, model_name]
self.add_to_migration(app_label,
operations.DeleteModel(model_state.name, ))
# Changes within models
kept_models = set(old_model_keys).intersection(new_model_keys)
old_fields = set()
new_fields = set()
unique_together_operations = []
for app_label, model_name in kept_models:
old_model_name = renamed_models.get((app_label, model_name),
model_name)
old_model_state = self.from_state.models[app_label, old_model_name]
new_model_state = self.to_state.models[app_label, model_name]
# Collect field changes for later global dealing with (so AddFields
# always come before AlterFields even on separate models)
old_fields.update(
(app_label, model_name, x) for x, y in old_model_state.fields)
new_fields.update(
(app_label, model_name, x) for x, y in new_model_state.fields)
# Unique_together changes. Operations will be added to migration a
# bit later, after fields creation. See ticket #22035.
if old_model_state.options.get(
"unique_together", set()) != new_model_state.options.get(
"unique_together", set()):
unique_together_operations.append(
(app_label,
operations.AlterUniqueTogether(
name=model_name,
unique_together=new_model_state.options.get(
"unique_together", set()),
)))
# New fields
renamed_fields = {}
for app_label, model_name, field_name in new_fields - old_fields:
old_model_name = renamed_models.get((app_label, model_name),
model_name)
old_model_state = self.from_state.models[app_label, old_model_name]
new_model_state = self.to_state.models[app_label, model_name]
field = new_model_state.get_field_by_name(field_name)
# Scan to see if this is actually a rename!
field_dec = field.deconstruct()[1:]
found_rename = False
for rem_app_label, rem_model_name, rem_field_name in (old_fields -
new_fields):
if rem_app_label == app_label and rem_model_name == model_name:
old_field_dec = old_model_state.get_field_by_name(
rem_field_name).deconstruct()[1:]
if field.rel and field.rel.to:
old_rel_to = old_field_dec[2]['to']
if old_rel_to in renamed_models_rel:
old_field_dec[2]['to'] = renamed_models_rel[
old_rel_to]
if old_field_dec == field_dec:
if self.questioner.ask_rename(model_name,
rem_field_name,
field_name, field):
self.add_to_migration(
app_label,
operations.RenameField(
model_name=model_name,
old_name=rem_field_name,
new_name=field_name,
))
old_fields.remove((rem_app_label, rem_model_name,
rem_field_name))
old_fields.add((app_label, model_name, field_name))
renamed_fields[app_label, model_name,
field_name] = rem_field_name
found_rename = True
break
if found_rename:
continue
# You can't just add NOT NULL fields with no default
if not field.null and not field.has_default():
field = field.clone()
field.default = self.questioner.ask_not_null_addition(
field_name, model_name)
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=field,
preserve_default=False,
))
else:
self.add_to_migration(
app_label,
operations.AddField(
model_name=model_name,
name=field_name,
field=field,
))
new_field = new_apps.get_model(
app_label,
model_name)._meta.get_field_by_name(field_name)[0]
swappable_setting = getattr(new_field, 'swappable_setting',
None)
if swappable_setting is not None:
self.add_swappable_dependency(app_label, swappable_setting)
# Old fields
for app_label, model_name, field_name in old_fields - new_fields:
old_model_name = renamed_models.get((app_label, model_name),
model_name)
old_model_state = self.from_state.models[app_label, old_model_name]
new_model_state = self.to_state.models[app_label, model_name]
self.add_to_migration(
app_label,
operations.RemoveField(
model_name=model_name,
name=field_name,
))
# The same fields
for app_label, model_name, field_name in old_fields.intersection(
new_fields):
# Did the field change?
old_model_name = renamed_models.get((app_label, model_name),
model_name)
old_model_state = self.from_state.models[app_label, old_model_name]
new_model_state = self.to_state.models[app_label, model_name]
old_field_name = renamed_fields.get(
(app_label, model_name, field_name), field_name)
old_field_dec = old_model_state.get_field_by_name(
old_field_name).deconstruct()[1:]
new_field_dec = new_model_state.get_field_by_name(
field_name).deconstruct()[1:]
if old_field_dec != new_field_dec:
self.add_to_migration(
app_label,
operations.AlterField(
model_name=model_name,
name=field_name,
field=new_model_state.get_field_by_name(field_name),
))
for app_label, operation in unique_together_operations:
self.add_to_migration(app_label, operation)
# Alright, now add internal dependencies
for app_label, migrations in self.migrations.items():
for m1, m2 in zip(migrations, migrations[1:]):
m2.dependencies.append((app_label, m1.name))
# Clean up dependencies
for app_label, migrations in self.migrations.items():
for migration in migrations:
migration.dependencies = list(set(migration.dependencies))
return self.migrations
