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from __future__ import print_function, unicode_literals
import importlib
import os
import sys
from django.apps import apps
from django.db.models.fields import NOT_PROVIDED
from django.utils import datetime_safe, six, timezone
from django.utils.six.moves import input
from .loader import MigrationLoader
class MigrationQuestioner(object):
"""
Gives the autodetector responses to questions it might have.
This base class has a built-in noninteractive mode, but the
interactive subclass is what the command-line arguments will use.
"""
def __init__(self, defaults=None, specified_apps=None, dry_run=None):
self.defaults = defaults or {}
self.specified_apps = specified_apps or set()
self.dry_run = dry_run
def ask_initial(self, app_label):
"Should we create an initial migration for the app?"
# If it was specified on the command line, definitely true
if app_label in self.specified_apps:
return True
# Otherwise, we look to see if it has a migrations module
# without any Python files in it, apart from __init__.py.
# Apps from the new app template will have these; the python
# file check will ensure we skip South ones.
try:
app_config = apps.get_app_config(app_label)
except LookupError: # It's a fake app.
return self.defaults.get("ask_initial", False)
migrations_import_path = MigrationLoader.migrations_module(app_config.label)
try:
migrations_module = importlib.import_module(migrations_import_path)
except ImportError:
return self.defaults.get("ask_initial", False)
else:
if hasattr(migrations_module, "__file__"):
filenames = os.listdir(os.path.dirname(migrations_module.__file__))
elif hasattr(migrations_module, "__path__"):
if len(migrations_module.__path__) > 1:
return False
filenames = os.listdir(list(migrations_module.__path__)[0])
return not any(x.endswith(".py") for x in filenames if x != "__init__.py")
def ask_not_null_addition(self, field_name, model_name):
"Adding a NOT NULL field to a model"
# None means quit
return None
def ask_not_null_alteration(self, field_name, model_name):
"Changing a NULL field to NOT NULL"
# None means quit
return None
def ask_rename(self, model_name, old_name, new_name, field_instance):
"Was this field really renamed?"
return self.defaults.get("ask_rename", False)
def ask_rename_model(self, old_model_state, new_model_state):
"Was this model really renamed?"
return self.defaults.get("ask_rename_model", False)
def ask_merge(self, app_label):
"Do you really want to merge these migrations?"
return self.defaults.get("ask_merge", False)
class InteractiveMigrationQuestioner(MigrationQuestioner):
def _boolean_input(self, question, default=None):
result = input("%s " % question)
if not result and default is not None:
return default
while len(result) < 1 or result[0].lower() not in "yn":
result = input("Please answer yes or no: ")
return result[0].lower() == "y"
def _choice_input(self, question, choices):
print(question)
for i, choice in enumerate(choices):
print(" %s) %s" % (i + 1, choice))
result = input("Select an option: ")
while True:
try:
value = int(result)
if 0 < value <= len(choices):
return value
except ValueError:
pass
result = input("Please select a valid option: ")
def _ask_default(self):
print("Please enter the default value now, as valid Python")
print("The datetime and django.utils.timezone modules are available, so you can do e.g. timezone.now()")
while True:
if six.PY3:
# Six does not correctly abstract over the fact that
# py3 input returns a unicode string, while py2 raw_input
# returns a bytestring.
code = input(">>> ")
else:
code = input(">>> ").decode(sys.stdin.encoding)
if not code:
print("Please enter some code, or 'exit' (with no quotes) to exit.")
elif code == "exit":
sys.exit(1)
else:
try:
return eval(code, {}, {"datetime": datetime_safe, "timezone": timezone})
except (SyntaxError, NameError) as e:
print("Invalid input: %s" % e)
def ask_not_null_addition(self, field_name, model_name):
"Adding a NOT NULL field to a model"
if not self.dry_run:
choice = self._choice_input(
"You are trying to add a non-nullable field '%s' to %s without a default; "
"we can't do that (the database needs something to populate existing rows).\n"
"Please select a fix:" % (field_name, model_name),
[
"Provide a one-off default now (will be set on all existing rows)",
"Quit, and let me add a default in models.py",
]
)
if choice == 2:
sys.exit(3)
else:
return self._ask_default()
return None
def ask_not_null_alteration(self, field_name, model_name):
"Changing a NULL field to NOT NULL"
if not self.dry_run:
choice = self._choice_input(
"You are trying to change the nullable field '%s' on %s to non-nullable "
"without a default; we can't do that (the database needs something to "
"populate existing rows).\n"
"Please select a fix:" % (field_name, model_name),
[
"Provide a one-off default now (will be set on all existing rows)",
("Ignore for now, and let me handle existing rows with NULL myself "
"(e.g. because you added a RunPython or RunSQL operation to handle "
"NULL values in a previous data migration)"),
"Quit, and let me add a default in models.py",
]
)
if choice == 2:
return NOT_PROVIDED
elif choice == 3:
sys.exit(3)
else:
return self._ask_default()
return None
def ask_rename(self, model_name, old_name, new_name, field_instance):
"Was this field really renamed?"
msg = "Did you rename %s.%s to %s.%s (a %s)? [y/N]"
return self._boolean_input(msg % (model_name, old_name, model_name, new_name,
field_instance.__class__.__name__), False)
def ask_rename_model(self, old_model_state, new_model_state):
"Was this model really renamed?"
msg = "Did you rename the %s.%s model to %s? [y/N]"
return self._boolean_input(msg % (old_model_state.app_label, old_model_state.name,
new_model_state.name), False)
def ask_merge(self, app_label):
return self._boolean_input(
"\nMerging will only work if the operations printed above do not conflict\n" +
"with each other (working on different fields or models)\n" +
"Do you want to merge these migration branches? [y/N]",
False,
)
class NonInteractiveMigrationQuestioner(MigrationQuestioner):
def ask_not_null_addition(self, field_name, model_name):
# We can't ask the user, so act like the user aborted.
sys.exit(3)
def ask_not_null_alteration(self, field_name, model_name):
# We can't ask the user, so set as not provided.
return NOT_PROVIDED
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