def _get_dependency_objects(self, attrname):
"""
Given the name of an attribute (depends_on or needed_by), either yields
a list of migration objects representing it, or errors out.
"""
for app, name in getattr(self.migration_class(), attrname, []):
try:
migrations = Migrations(app)
except ImproperlyConfigured:
raise exceptions.DependsOnUnmigratedApplication(self, app)
migration = migrations.migration(name)
try:
migration.migration()
except exceptions.UnknownMigration:
raise exceptions.DependsOnUnknownMigration(self, migration)
if migration.is_before(self) == False:
raise exceptions.DependsOnHigherMigration(self, migration)
yield migration
def dependencies(self):
"Returns the list of migrations this migration depends on."
result = [self.previous()]
if result[0] is None:
result = []
# Get forwards dependencies
for app, name in getattr(self.migration_class(), 'depends_on', []):
try:
migrations = Migrations(app)
except ImproperlyConfigured:
raise exceptions.DependsOnUnmigratedApplication(self, app)
migration = migrations.migration(name)
try:
migration.migration()
except exceptions.UnknownMigration:
raise exceptions.DependsOnUnknownMigration(self, migration)
if migration.is_before(self) == False:
raise exceptions.DependsOnHigherMigration(self, migration)
result.append(migration)
return result
