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)
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 test_migration_file_header_comments(self):
"""
Test comments at top of file.
"""
migration = type("Migration", (migrations.Migration, ),
{"operations": []})
dt = datetime.datetime(2015, 7, 31, 4, 40, 0, 0, tzinfo=utc)
with mock.patch('djmodels.db.migrations.writer.now', lambda: dt):
writer = MigrationWriter(migration)
output = writer.as_string()
self.assertTrue(
output.startswith(
"# Generated by Django %(version)s on 2015-07-31 04:40\n" % {
'version': get_version(),
}))
def test_models_import_omitted(self):
"""
djmodels.db.models shouldn't be imported if unused.
"""
migration = type(
"Migration", (migrations.Migration, ), {
"operations": [
migrations.AlterModelOptions(
name='model',
options={
'verbose_name': 'model',
'verbose_name_plural': 'models'
},
),
]
})
writer = MigrationWriter(migration)
output = writer.as_string()
self.assertIn("from djmodels.db import migrations\n", output)
def test_sorted_imports(self):
"""
#24155 - Tests ordering of imports.
"""
migration = type(
"Migration", (migrations.Migration, ), {
"operations": [
migrations.AddField(
"mymodel", "myfield",
models.DateTimeField(default=datetime.datetime(
2012, 1, 1, 1, 1, tzinfo=utc), )),
]
})
writer = MigrationWriter(migration)
output = writer.as_string()
self.assertIn(
"import datetime\n"
"from djmodels.db import migrations, models\n"
"from djmodels.utils.timezone import utc\n", output)
def test_custom_operation(self):
migration = type(
"Migration", (migrations.Migration, ), {
"operations": [
custom_migration_operations.operations.TestOperation(),
custom_migration_operations.operations.CreateModel(),
migrations.CreateModel("MyModel", (), {},
(models.Model, )),
custom_migration_operations.more_operations.TestOperation(
)
],
"dependencies": []
})
writer = MigrationWriter(migration)
output = writer.as_string()
result = self.safe_exec(output)
self.assertIn("custom_migration_operations", result)
self.assertNotEqual(
result['custom_migration_operations'].operations.TestOperation,
result['custom_migration_operations'].more_operations.TestOperation
)
def test_simple_migration(self):
"""
Tests serializing a simple migration.
"""
fields = {
'charfield':
models.DateTimeField(default=datetime.datetime.utcnow),
'datetimefield':
models.DateTimeField(default=datetime.datetime.utcnow),
}
options = {
'verbose_name': 'My model',
'verbose_name_plural': 'My models',
}
migration = type(
"Migration", (migrations.Migration, ), {
"operations": [
migrations.CreateModel("MyModel", tuple(fields.items()),
options, (models.Model, )),
migrations.CreateModel("MyModel2",
tuple(fields.items()),
bases=(models.Model, )),
migrations.CreateModel(name="MyModel3",
fields=tuple(fields.items()),
options=options,
bases=(models.Model, )),
migrations.DeleteModel("MyModel"),
migrations.AddField("OtherModel", "datetimefield",
fields["datetimefield"]),
],
"dependencies": [("testapp", "some_other_one")],
})
writer = MigrationWriter(migration)
output = writer.as_string()
# We don't test the output formatting - that's too fragile.
# Just make sure it runs for now, and that things look alright.
result = self.safe_exec(output)
self.assertIn("Migration", result)
def handle(self, **options):
self.verbosity = options['verbosity']
self.interactive = options['interactive']
app_label = options['app_label']
start_migration_name = options['start_migration_name']
migration_name = options['migration_name']
no_optimize = options['no_optimize']
squashed_name = options['squashed_name']
# Validate app_label.
try:
apps.get_app_config(app_label)
except LookupError as err:
raise CommandError(str(err))
# Load the current graph state, check the app and migration they asked for exists
loader = MigrationLoader(connections[DEFAULT_DB_ALIAS])
if app_label not in loader.migrated_apps:
raise CommandError(
"App '%s' does not have migrations (so squashmigrations on "
"it makes no sense)" % app_label
)
migration = self.find_migration(loader, app_label, migration_name)
# Work out the list of predecessor migrations
migrations_to_squash = [
loader.get_migration(al, mn)
for al, mn in loader.graph.forwards_plan((migration.app_label, migration.name))
if al == migration.app_label
]
if start_migration_name:
start_migration = self.find_migration(loader, app_label, start_migration_name)
start = loader.get_migration(start_migration.app_label, start_migration.name)
try:
start_index = migrations_to_squash.index(start)
migrations_to_squash = migrations_to_squash[start_index:]
except ValueError:
raise CommandError(
"The migration '%s' cannot be found. Maybe it comes after "
"the migration '%s'?\n"
"Have a look at:\n"
" python manage.py showmigrations %s\n"
"to debug this issue." % (start_migration, migration, app_label)
)
# Tell them what we're doing and optionally ask if we should proceed
if self.verbosity > 0 or self.interactive:
self.stdout.write(self.style.MIGRATE_HEADING("Will squash the following migrations:"))
for migration in migrations_to_squash:
self.stdout.write(" - %s" % migration.name)
if self.interactive:
answer = None
while not answer or answer not in "yn":
answer = input("Do you wish to proceed? [yN] ")
if not answer:
answer = "n"
break
else:
answer = answer[0].lower()
if answer != "y":
return
# Load the operations from all those migrations and concat together,
# along with collecting external dependencies and detecting
# double-squashing
operations = []
dependencies = set()
# We need to take all dependencies from the first migration in the list
# as it may be 0002 depending on 0001
first_migration = True
for smigration in migrations_to_squash:
if smigration.replaces:
raise CommandError(
"You cannot squash squashed migrations! Please transition "
"it to a normal migration first: "
"https://docs.djangoproject.com/en/%s/topics/migrations/#squashing-migrations" % get_docs_version()
)
operations.extend(smigration.operations)
for dependency in smigration.dependencies:
if isinstance(dependency, SwappableTuple):
if settings.AUTH_USER_MODEL == dependency.setting:
dependencies.add(("__setting__", "AUTH_USER_MODEL"))
else:
dependencies.add(dependency)
elif dependency[0] != smigration.app_label or first_migration:
dependencies.add(dependency)
first_migration = False
if no_optimize:
if self.verbosity > 0:
self.stdout.write(self.style.MIGRATE_HEADING("(Skipping optimization.)"))
new_operations = operations
else:
if self.verbosity > 0:
self.stdout.write(self.style.MIGRATE_HEADING("Optimizing..."))
optimizer = MigrationOptimizer()
new_operations = optimizer.optimize(operations, migration.app_label)
if self.verbosity > 0:
if len(new_operations) == len(operations):
self.stdout.write(" No optimizations possible.")
else:
self.stdout.write(
" Optimized from %s operations to %s operations." %
(len(operations), len(new_operations))
)
# Work out the value of replaces (any squashed ones we're re-squashing)
# need to feed their replaces into ours
replaces = []
for migration in migrations_to_squash:
if migration.replaces:
replaces.extend(migration.replaces)
else:
replaces.append((migration.app_label, migration.name))
# Make a new migration with those operations
subclass = type("Migration", (migrations.Migration,), {
"dependencies": dependencies,
"operations": new_operations,
"replaces": replaces,
})
if start_migration_name:
if squashed_name:
# Use the name from --squashed-name.
prefix, _ = start_migration.name.split('_', 1)
name = '%s_%s' % (prefix, squashed_name)
else:
# Generate a name.
name = '%s_squashed_%s' % (start_migration.name, migration.name)
new_migration = subclass(name, app_label)
else:
name = '0001_%s' % (squashed_name or 'squashed_%s' % migration.name)
new_migration = subclass(name, app_label)
new_migration.initial = True
# Write out the new migration file
writer = MigrationWriter(new_migration)
with open(writer.path, "w", encoding='utf-8') as fh:
fh.write(writer.as_string())
if self.verbosity > 0:
self.stdout.write(self.style.MIGRATE_HEADING("Created new squashed migration %s" % writer.path))
self.stdout.write(" You should commit this migration but leave the old ones in place;")
self.stdout.write(" the new migration will be used for new installs. Once you are sure")
self.stdout.write(" all instances of the codebase have applied the migrations you squashed,")
self.stdout.write(" you can delete them.")
if writer.needs_manual_porting:
self.stdout.write(self.style.MIGRATE_HEADING("Manual porting required"))
self.stdout.write(" Your migrations contained functions that must be manually copied over,")
self.stdout.write(" as we could not safely copy their implementation.")
self.stdout.write(" See the comment at the top of the squashed migration for details.")
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)
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())