123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311 |
- import os
- import sys
- from itertools import takewhile
-
- from django.apps import apps
- from django.conf import settings
- from django.core.management.base import (
- BaseCommand, CommandError, no_translations,
- )
- from django.db import DEFAULT_DB_ALIAS, connections, router
- from django.db.migrations import Migration
- from django.db.migrations.autodetector import MigrationAutodetector
- from django.db.migrations.loader import MigrationLoader
- from django.db.migrations.questioner import (
- InteractiveMigrationQuestioner, MigrationQuestioner,
- NonInteractiveMigrationQuestioner,
- )
- from django.db.migrations.state import ProjectState
- from django.db.migrations.utils import get_migration_name_timestamp
- from django.db.migrations.writer import MigrationWriter
-
-
- class Command(BaseCommand):
- help = "Creates new migration(s) for apps."
-
- def add_arguments(self, parser):
- parser.add_argument(
- 'args', metavar='app_label', nargs='*',
- help='Specify the app label(s) to create migrations for.',
- )
- parser.add_argument(
- '--dry-run', action='store_true',
- help="Just show what migrations would be made; don't actually write them.",
- )
- parser.add_argument(
- '--merge', action='store_true',
- help="Enable fixing of migration conflicts.",
- )
- parser.add_argument(
- '--empty', action='store_true',
- help="Create an empty migration.",
- )
- parser.add_argument(
- '--noinput', '--no-input', action='store_false', dest='interactive',
- help='Tells Django to NOT prompt the user for input of any kind.',
- )
- parser.add_argument(
- '-n', '--name',
- help="Use this name for migration file(s).",
- )
- parser.add_argument(
- '--no-header', action='store_false', dest='include_header',
- help='Do not add header comments to new migration file(s).',
- )
- parser.add_argument(
- '--check', action='store_true', dest='check_changes',
- help='Exit with a non-zero status if model changes are missing migrations.',
- )
-
- @no_translations
- def handle(self, *app_labels, **options):
- self.verbosity = options['verbosity']
- self.interactive = options['interactive']
- self.dry_run = options['dry_run']
- self.merge = options['merge']
- self.empty = options['empty']
- self.migration_name = options['name']
- if self.migration_name and not self.migration_name.isidentifier():
- raise CommandError('The migration name must be a valid Python identifier.')
- self.include_header = options['include_header']
- check_changes = options['check_changes']
-
- # Make sure the app they asked for exists
- app_labels = set(app_labels)
- has_bad_labels = False
- for app_label in app_labels:
- try:
- apps.get_app_config(app_label)
- except LookupError as err:
- self.stderr.write(str(err))
- has_bad_labels = True
- if has_bad_labels:
- sys.exit(2)
-
- # Load the current graph state. Pass in None for the connection so
- # the loader doesn't try to resolve replaced migrations from DB.
- loader = MigrationLoader(None, ignore_no_migrations=True)
-
- # Raise an error if any migrations are applied before their dependencies.
- consistency_check_labels = {config.label for config in apps.get_app_configs()}
- # Non-default databases are only checked if database routers used.
- aliases_to_check = connections if settings.DATABASE_ROUTERS else [DEFAULT_DB_ALIAS]
- for alias in sorted(aliases_to_check):
- connection = connections[alias]
- if (connection.settings_dict['ENGINE'] != 'django.db.backends.dummy' and any(
- # At least one model must be migrated to the database.
- router.allow_migrate(connection.alias, app_label, model_name=model._meta.object_name)
- for app_label in consistency_check_labels
- for model in apps.get_app_config(app_label).get_models()
- )):
- loader.check_consistent_history(connection)
-
- # Before anything else, see if there's conflicting apps and drop out
- # hard if there are any and they don't want to merge
- conflicts = loader.detect_conflicts()
-
- # If app_labels is specified, filter out conflicting migrations for unspecified apps
- if app_labels:
- conflicts = {
- app_label: conflict for app_label, conflict in conflicts.items()
- if app_label in app_labels
- }
-
- if conflicts and not self.merge:
- name_str = "; ".join(
- "%s in %s" % (", ".join(names), app)
- for app, names in conflicts.items()
- )
- raise CommandError(
- "Conflicting migrations detected; multiple leaf nodes in the "
- "migration graph: (%s).\nTo fix them run "
- "'python manage.py makemigrations --merge'" % name_str
- )
-
- # If they want to merge and there's nothing to merge, then politely exit
- if self.merge and not conflicts:
- self.stdout.write("No conflicts detected to merge.")
- return
-
- # If they want to merge and there is something to merge, then
- # divert into the merge code
- if self.merge and conflicts:
- return self.handle_merge(loader, conflicts)
-
- if self.interactive:
- questioner = InteractiveMigrationQuestioner(specified_apps=app_labels, dry_run=self.dry_run)
- else:
- questioner = NonInteractiveMigrationQuestioner(specified_apps=app_labels, dry_run=self.dry_run)
- # Set up autodetector
- autodetector = MigrationAutodetector(
- loader.project_state(),
- ProjectState.from_apps(apps),
- questioner,
- )
-
- # If they want to make an empty migration, make one for each app
- if self.empty:
- if not app_labels:
- raise CommandError("You must supply at least one app label when using --empty.")
- # Make a fake changes() result we can pass to arrange_for_graph
- changes = {
- app: [Migration("custom", app)]
- for app in app_labels
- }
- changes = autodetector.arrange_for_graph(
- changes=changes,
- graph=loader.graph,
- migration_name=self.migration_name,
- )
- self.write_migration_files(changes)
- return
-
- # Detect changes
- changes = autodetector.changes(
- graph=loader.graph,
- trim_to_apps=app_labels or None,
- convert_apps=app_labels or None,
- migration_name=self.migration_name,
- )
-
- if not changes:
- # No changes? Tell them.
- if self.verbosity >= 1:
- if app_labels:
- if len(app_labels) == 1:
- self.stdout.write("No changes detected in app '%s'" % app_labels.pop())
- else:
- self.stdout.write("No changes detected in apps '%s'" % ("', '".join(app_labels)))
- else:
- self.stdout.write("No changes detected")
- else:
- self.write_migration_files(changes)
- if check_changes:
- sys.exit(1)
-
- def write_migration_files(self, changes):
- """
- Take a changes dict and write them out as migration files.
- """
- directory_created = {}
- for app_label, app_migrations in changes.items():
- if self.verbosity >= 1:
- self.stdout.write(self.style.MIGRATE_HEADING("Migrations for '%s':" % app_label) + "\n")
- for migration in app_migrations:
- # Describe the migration
- writer = MigrationWriter(migration, self.include_header)
- if self.verbosity >= 1:
- # Display a relative path if it's below the current working
- # directory, or an absolute path otherwise.
- try:
- migration_string = os.path.relpath(writer.path)
- except ValueError:
- migration_string = writer.path
- if migration_string.startswith('..'):
- migration_string = writer.path
- self.stdout.write(" %s\n" % (self.style.MIGRATE_LABEL(migration_string),))
- for operation in migration.operations:
- self.stdout.write(" - %s\n" % operation.describe())
- if not self.dry_run:
- # Write the migrations file to the disk.
- migrations_directory = os.path.dirname(writer.path)
- if not directory_created.get(app_label):
- if not os.path.isdir(migrations_directory):
- os.mkdir(migrations_directory)
- init_path = os.path.join(migrations_directory, "__init__.py")
- if not os.path.isfile(init_path):
- open(init_path, "w").close()
- # We just do this once per app
- directory_created[app_label] = True
- migration_string = writer.as_string()
- with open(writer.path, "w", encoding='utf-8') as fh:
- fh.write(migration_string)
- elif self.verbosity == 3:
- # Alternatively, makemigrations --dry-run --verbosity 3
- # will output the migrations to stdout rather than saving
- # the file to the disk.
- self.stdout.write(self.style.MIGRATE_HEADING(
- "Full migrations file '%s':" % writer.filename) + "\n"
- )
- self.stdout.write("%s\n" % writer.as_string())
-
- def handle_merge(self, loader, conflicts):
- """
- Handles merging together conflicted migrations interactively,
- if it's safe; otherwise, advises on how to fix it.
- """
- if self.interactive:
- questioner = InteractiveMigrationQuestioner()
- else:
- questioner = MigrationQuestioner(defaults={'ask_merge': True})
-
- for app_label, migration_names in conflicts.items():
- # Grab out the migrations in question, and work out their
- # common ancestor.
- merge_migrations = []
- for migration_name in migration_names:
- migration = loader.get_migration(app_label, migration_name)
- migration.ancestry = [
- mig for mig in loader.graph.forwards_plan((app_label, migration_name))
- if mig[0] == migration.app_label
- ]
- merge_migrations.append(migration)
-
- def all_items_equal(seq):
- return all(item == seq[0] for item in seq[1:])
-
- merge_migrations_generations = zip(*(m.ancestry for m in merge_migrations))
- common_ancestor_count = sum(1 for common_ancestor_generation
- in takewhile(all_items_equal, merge_migrations_generations))
- if not common_ancestor_count:
- raise ValueError("Could not find common ancestor of %s" % migration_names)
- # Now work out the operations along each divergent branch
- for migration in merge_migrations:
- migration.branch = migration.ancestry[common_ancestor_count:]
- migrations_ops = (loader.get_migration(node_app, node_name).operations
- for node_app, node_name in migration.branch)
- migration.merged_operations = sum(migrations_ops, [])
- # In future, this could use some of the Optimizer code
- # (can_optimize_through) to automatically see if they're
- # mergeable. For now, we always just prompt the user.
- if self.verbosity > 0:
- self.stdout.write(self.style.MIGRATE_HEADING("Merging %s" % app_label))
- for migration in merge_migrations:
- self.stdout.write(self.style.MIGRATE_LABEL(" Branch %s" % migration.name))
- for operation in migration.merged_operations:
- self.stdout.write(" - %s\n" % operation.describe())
- if questioner.ask_merge(app_label):
- # If they still want to merge it, then write out an empty
- # file depending on the migrations needing merging.
- numbers = [
- MigrationAutodetector.parse_number(migration.name)
- for migration in merge_migrations
- ]
- try:
- biggest_number = max(x for x in numbers if x is not None)
- except ValueError:
- biggest_number = 1
- subclass = type("Migration", (Migration,), {
- "dependencies": [(app_label, migration.name) for migration in merge_migrations],
- })
- migration_name = "%04i_%s" % (
- biggest_number + 1,
- self.migration_name or ("merge_%s" % get_migration_name_timestamp())
- )
- new_migration = subclass(migration_name, app_label)
- writer = MigrationWriter(new_migration, self.include_header)
-
- if not self.dry_run:
- # Write the merge migrations file to the disk
- with open(writer.path, "w", encoding='utf-8') as fh:
- fh.write(writer.as_string())
- if self.verbosity > 0:
- self.stdout.write("\nCreated new merge migration %s" % writer.path)
- elif self.verbosity == 3:
- # Alternatively, makemigrations --merge --dry-run --verbosity 3
- # will output the merge migrations to stdout rather than saving
- # the file to the disk.
- self.stdout.write(self.style.MIGRATE_HEADING(
- "Full merge migrations file '%s':" % writer.filename) + "\n"
- )
- self.stdout.write("%s\n" % writer.as_string())
|