180 lines
8.5 KiB
Python
180 lines
8.5 KiB
Python
import sys
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import os
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import operator
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from optparse import make_option
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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.db import connections, DEFAULT_DB_ALIAS, migrations
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from django.db.migrations.loader import MigrationLoader
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from django.db.migrations.autodetector import MigrationAutodetector
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from django.db.migrations.questioner import MigrationQuestioner, InteractiveMigrationQuestioner
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from django.db.migrations.state import ProjectState
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from django.db.migrations.writer import MigrationWriter
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from django.utils.six.moves import reduce
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class Command(BaseCommand):
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option_list = BaseCommand.option_list + (
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make_option('--dry-run', action='store_true', dest='dry_run', default=False,
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help="Just show what migrations would be made; don't actually write them."),
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make_option('--merge', action='store_true', dest='merge', default=False,
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help="Enable fixing of migration conflicts."),
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)
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help = "Creates new migration(s) for apps."
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usage_str = "Usage: ./manage.py makemigrations [--dry-run] [app [app ...]]"
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def handle(self, *app_labels, **options):
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self.verbosity = int(options.get('verbosity'))
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self.interactive = options.get('interactive')
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self.dry_run = options.get('dry_run', False)
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self.merge = options.get('merge', False)
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# Make sure the app they asked for exists
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app_labels = set(app_labels)
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bad_app_labels = set()
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for app_label in app_labels:
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try:
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apps.get_app_config(app_label)
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except LookupError:
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bad_app_labels.add(app_label)
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if bad_app_labels:
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for app_label in bad_app_labels:
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self.stderr.write("App '%s' could not be found. Is it in INSTALLED_APPS?" % app_label)
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sys.exit(2)
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# Load the current graph state. Takes a connection, but it's not used
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# (makemigrations doesn't look at the database state).
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loader = MigrationLoader(connections[DEFAULT_DB_ALIAS])
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# Before anything else, see if there's conflicting apps and drop out
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# hard if there are any and they don't want to merge
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conflicts = loader.detect_conflicts()
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if conflicts and not self.merge:
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name_str = "; ".join(
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"%s in %s" % (", ".join(names), app)
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for app, names in conflicts.items()
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)
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raise CommandError("Conflicting migrations detected (%s).\nTo fix them run 'python manage.py makemigrations --merge'" % name_str)
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# If they want to merge and there's nothing to merge, then politely exit
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if self.merge and not conflicts:
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self.stdout.write("No conflicts detected to merge.")
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return
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# If they want to merge and there is something to merge, then
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# divert into the merge code
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if self.merge and conflicts:
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return self.handle_merge(loader, conflicts)
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# Detect changes
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autodetector = MigrationAutodetector(
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loader.graph.project_state(),
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ProjectState.from_apps(apps),
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InteractiveMigrationQuestioner(specified_apps=app_labels),
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)
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changes = autodetector.changes(graph=loader.graph, trim_to_apps=app_labels or None)
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# No changes? Tell them.
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if not changes and self.verbosity >= 1:
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if len(app_labels) == 1:
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self.stdout.write("No changes detected in app '%s'" % app_labels.pop())
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elif len(app_labels) > 1:
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self.stdout.write("No changes detected in apps '%s'" % ("', '".join(app_labels)))
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else:
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self.stdout.write("No changes detected")
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return
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directory_created = {}
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for app_label, app_migrations in changes.items():
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if self.verbosity >= 1:
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self.stdout.write(self.style.MIGRATE_HEADING("Migrations for '%s':" % app_label) + "\n")
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for migration in app_migrations:
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# Describe the migration
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writer = MigrationWriter(migration)
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if self.verbosity >= 1:
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self.stdout.write(" %s:\n" % (self.style.MIGRATE_LABEL(writer.filename),))
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for operation in migration.operations:
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self.stdout.write(" - %s\n" % operation.describe())
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# Write it
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if not self.dry_run:
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migrations_directory = os.path.dirname(writer.path)
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if not directory_created.get(app_label, False):
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if not os.path.isdir(migrations_directory):
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os.mkdir(migrations_directory)
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init_path = os.path.join(migrations_directory, "__init__.py")
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if not os.path.isfile(init_path):
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open(init_path, "w").close()
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# We just do this once per app
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directory_created[app_label] = True
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migration_string = writer.as_string()
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with open(writer.path, "wb") as fh:
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fh.write(migration_string)
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def handle_merge(self, loader, conflicts):
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"""
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Handles merging together conflicted migrations interactively,
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if it's safe; otherwise, advises on how to fix it.
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"""
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if self.interactive:
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questioner = InteractiveMigrationQuestioner()
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else:
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questioner = MigrationQuestioner()
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for app_label, migration_names in conflicts.items():
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# Grab out the migrations in question, and work out their
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# common ancestor.
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merge_migrations = []
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for migration_name in migration_names:
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migration = loader.get_migration(app_label, migration_name)
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migration.ancestry = loader.graph.forwards_plan((app_label, migration_name))
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merge_migrations.append(migration)
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common_ancestor = None
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for level in zip(*[m.ancestry for m in merge_migrations]):
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if reduce(operator.eq, level):
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common_ancestor = level[0]
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else:
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break
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if common_ancestor is None:
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raise ValueError("Could not find common ancestor of %s" % migration_names)
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# Now work out the operations along each divergent branch
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for migration in merge_migrations:
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migration.branch = migration.ancestry[
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(migration.ancestry.index(common_ancestor) + 1):
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]
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migration.merged_operations = []
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for node_app, node_name in migration.branch:
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migration.merged_operations.extend(
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loader.get_migration(node_app, node_name).operations
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)
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# In future, this could use some of the Optimizer code
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# (can_optimize_through) to automatically see if they're
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# mergeable. For now, we always just prompt the user.
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if self.verbosity > 0:
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self.stdout.write(self.style.MIGRATE_HEADING("Merging %s" % app_label))
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for migration in merge_migrations:
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self.stdout.write(self.style.MIGRATE_LABEL(" Branch %s" % migration.name))
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for operation in migration.merged_operations:
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self.stdout.write(" - %s\n" % operation.describe())
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if questioner.ask_merge(app_label):
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# If they still want to merge it, then write out an empty
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# file depending on the migrations needing merging.
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numbers = [
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MigrationAutodetector.parse_number(migration.name)
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for migration in merge_migrations
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]
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try:
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biggest_number = max([x for x in numbers if x is not None])
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except ValueError:
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biggest_number = 1
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subclass = type("Migration", (migrations.Migration, ), {
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"dependencies": [(app_label, migration.name) for migration in merge_migrations],
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})
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new_migration = subclass("%04i_merge" % (biggest_number + 1), app_label)
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writer = MigrationWriter(new_migration)
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with open(writer.path, "wb") as fh:
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fh.write(writer.as_string())
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if self.verbosity > 0:
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self.stdout.write("\nCreated new merge migration %s" % writer.path)
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