380 lines
14 KiB
Python
380 lines
14 KiB
Python
from django.core.exceptions import FieldDoesNotExist
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from django.db.models import NOT_PROVIDED
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from django.utils.functional import cached_property
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from .base import Operation
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from .utils import field_is_referenced, field_references, get_references
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class FieldOperation(Operation):
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def __init__(self, model_name, name, field=None):
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self.model_name = model_name
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self.name = name
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self.field = field
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@cached_property
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def model_name_lower(self):
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return self.model_name.lower()
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@cached_property
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def name_lower(self):
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return self.name.lower()
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def is_same_model_operation(self, operation):
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return self.model_name_lower == operation.model_name_lower
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def is_same_field_operation(self, operation):
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return self.is_same_model_operation(operation) and self.name_lower == operation.name_lower
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def references_model(self, name, app_label):
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name_lower = name.lower()
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if name_lower == self.model_name_lower:
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return True
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if self.field:
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return bool(field_references(
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(app_label, self.model_name_lower), self.field, (app_label, name_lower)
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))
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return False
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def references_field(self, model_name, name, app_label):
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model_name_lower = model_name.lower()
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# Check if this operation locally references the field.
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if model_name_lower == self.model_name_lower:
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if name == self.name:
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return True
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elif self.field and hasattr(self.field, 'from_fields') and name in self.field.from_fields:
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return True
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# Check if this operation remotely references the field.
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if self.field is None:
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return False
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return bool(field_references(
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(app_label, self.model_name_lower),
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self.field,
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(app_label, model_name_lower),
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name,
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))
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def reduce(self, operation, app_label):
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return (
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super().reduce(operation, app_label) or
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not operation.references_field(self.model_name, self.name, app_label)
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)
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class AddField(FieldOperation):
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"""Add a field to a model."""
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def __init__(self, model_name, name, field, preserve_default=True):
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self.preserve_default = preserve_default
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super().__init__(model_name, name, field)
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def deconstruct(self):
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kwargs = {
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'model_name': self.model_name,
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'name': self.name,
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'field': self.field,
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}
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if self.preserve_default is not True:
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kwargs['preserve_default'] = self.preserve_default
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return (
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self.__class__.__name__,
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[],
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kwargs
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)
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def state_forwards(self, app_label, state):
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# If preserve default is off, don't use the default for future state
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if not self.preserve_default:
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field = self.field.clone()
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field.default = NOT_PROVIDED
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else:
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field = self.field
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state.models[app_label, self.model_name_lower].fields[self.name] = field
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# Delay rendering of relationships if it's not a relational field
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delay = not field.is_relation
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state.reload_model(app_label, self.model_name_lower, delay=delay)
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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to_model = to_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, to_model):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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field = to_model._meta.get_field(self.name)
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if not self.preserve_default:
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field.default = self.field.default
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schema_editor.add_field(
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from_model,
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field,
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)
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if not self.preserve_default:
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field.default = NOT_PROVIDED
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, from_model):
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schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
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def describe(self):
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return "Add field %s to %s" % (self.name, self.model_name)
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def reduce(self, operation, app_label):
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if isinstance(operation, FieldOperation) and self.is_same_field_operation(operation):
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if isinstance(operation, AlterField):
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return [
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AddField(
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model_name=self.model_name,
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name=operation.name,
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field=operation.field,
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),
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]
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elif isinstance(operation, RemoveField):
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return []
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elif isinstance(operation, RenameField):
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return [
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AddField(
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model_name=self.model_name,
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name=operation.new_name,
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field=self.field,
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),
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]
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return super().reduce(operation, app_label)
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class RemoveField(FieldOperation):
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"""Remove a field from a model."""
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def deconstruct(self):
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kwargs = {
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'model_name': self.model_name,
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'name': self.name,
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}
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return (
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self.__class__.__name__,
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[],
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kwargs
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)
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def state_forwards(self, app_label, state):
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model_state = state.models[app_label, self.model_name_lower]
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old_field = model_state.fields.pop(self.name)
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# Delay rendering of relationships if it's not a relational field
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delay = not old_field.is_relation
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state.reload_model(app_label, self.model_name_lower, delay=delay)
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, from_model):
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schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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to_model = to_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, to_model):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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schema_editor.add_field(from_model, to_model._meta.get_field(self.name))
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def describe(self):
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return "Remove field %s from %s" % (self.name, self.model_name)
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def reduce(self, operation, app_label):
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from .models import DeleteModel
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if isinstance(operation, DeleteModel) and operation.name_lower == self.model_name_lower:
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return [operation]
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return super().reduce(operation, app_label)
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class AlterField(FieldOperation):
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"""
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Alter a field's database column (e.g. null, max_length) to the provided
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new field.
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"""
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def __init__(self, model_name, name, field, preserve_default=True):
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self.preserve_default = preserve_default
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super().__init__(model_name, name, field)
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def deconstruct(self):
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kwargs = {
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'model_name': self.model_name,
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'name': self.name,
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'field': self.field,
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}
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if self.preserve_default is not True:
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kwargs['preserve_default'] = self.preserve_default
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return (
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self.__class__.__name__,
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[],
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kwargs
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)
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def state_forwards(self, app_label, state):
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if not self.preserve_default:
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field = self.field.clone()
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field.default = NOT_PROVIDED
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else:
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field = self.field
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model_state = state.models[app_label, self.model_name_lower]
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model_state.fields[self.name] = field
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# TODO: investigate if old relational fields must be reloaded or if it's
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# sufficient if the new field is (#27737).
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# Delay rendering of relationships if it's not a relational field and
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# not referenced by a foreign key.
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delay = (
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not field.is_relation and
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not field_is_referenced(
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state, (app_label, self.model_name_lower), (self.name, field),
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)
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)
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state.reload_model(app_label, self.model_name_lower, delay=delay)
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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to_model = to_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, to_model):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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from_field = from_model._meta.get_field(self.name)
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to_field = to_model._meta.get_field(self.name)
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if not self.preserve_default:
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to_field.default = self.field.default
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schema_editor.alter_field(from_model, from_field, to_field)
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if not self.preserve_default:
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to_field.default = NOT_PROVIDED
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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self.database_forwards(app_label, schema_editor, from_state, to_state)
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def describe(self):
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return "Alter field %s on %s" % (self.name, self.model_name)
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def reduce(self, operation, app_label):
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if isinstance(operation, RemoveField) and self.is_same_field_operation(operation):
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return [operation]
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elif isinstance(operation, RenameField) and self.is_same_field_operation(operation):
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return [
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operation,
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AlterField(
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model_name=self.model_name,
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name=operation.new_name,
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field=self.field,
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),
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]
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return super().reduce(operation, app_label)
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class RenameField(FieldOperation):
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"""Rename a field on the model. Might affect db_column too."""
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def __init__(self, model_name, old_name, new_name):
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self.old_name = old_name
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self.new_name = new_name
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super().__init__(model_name, old_name)
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@cached_property
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def old_name_lower(self):
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return self.old_name.lower()
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@cached_property
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def new_name_lower(self):
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return self.new_name.lower()
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def deconstruct(self):
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kwargs = {
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'model_name': self.model_name,
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'old_name': self.old_name,
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'new_name': self.new_name,
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}
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return (
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self.__class__.__name__,
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[],
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kwargs
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)
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def state_forwards(self, app_label, state):
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model_state = state.models[app_label, self.model_name_lower]
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# Rename the field
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fields = model_state.fields
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try:
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found = fields.pop(self.old_name)
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except KeyError:
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raise FieldDoesNotExist(
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"%s.%s has no field named '%s'" % (app_label, self.model_name, self.old_name)
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)
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fields[self.new_name] = found
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for field in fields.values():
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# Fix from_fields to refer to the new field.
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from_fields = getattr(field, 'from_fields', None)
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if from_fields:
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field.from_fields = tuple([
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self.new_name if from_field_name == self.old_name else from_field_name
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for from_field_name in from_fields
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])
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# Fix index/unique_together to refer to the new field
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options = model_state.options
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for option in ('index_together', 'unique_together'):
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if option in options:
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options[option] = [
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[self.new_name if n == self.old_name else n for n in together]
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for together in options[option]
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]
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# Fix to_fields to refer to the new field.
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delay = True
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references = get_references(
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state, (app_label, self.model_name_lower), (self.old_name, found),
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)
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for *_, field, reference in references:
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delay = False
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if reference.to:
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remote_field, to_fields = reference.to
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if getattr(remote_field, 'field_name', None) == self.old_name:
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remote_field.field_name = self.new_name
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if to_fields:
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field.to_fields = tuple([
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self.new_name if to_field_name == self.old_name else to_field_name
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for to_field_name in to_fields
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])
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state.reload_model(app_label, self.model_name_lower, delay=delay)
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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to_model = to_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, to_model):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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schema_editor.alter_field(
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from_model,
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from_model._meta.get_field(self.old_name),
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to_model._meta.get_field(self.new_name),
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)
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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to_model = to_state.apps.get_model(app_label, self.model_name)
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if self.allow_migrate_model(schema_editor.connection.alias, to_model):
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from_model = from_state.apps.get_model(app_label, self.model_name)
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schema_editor.alter_field(
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from_model,
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from_model._meta.get_field(self.new_name),
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to_model._meta.get_field(self.old_name),
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)
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def describe(self):
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return "Rename field %s on %s to %s" % (self.old_name, self.model_name, self.new_name)
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def references_field(self, model_name, name, app_label):
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return self.references_model(model_name, app_label) and (
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name.lower() == self.old_name_lower or
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name.lower() == self.new_name_lower
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)
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def reduce(self, operation, app_label):
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if (isinstance(operation, RenameField) and
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self.is_same_model_operation(operation) and
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self.new_name_lower == operation.old_name_lower):
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return [
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RenameField(
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self.model_name,
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self.old_name,
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operation.new_name,
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),
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]
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# Skip `FieldOperation.reduce` as we want to run `references_field`
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# against self.new_name.
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return (
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super(FieldOperation, self).reduce(operation, app_label) or
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not operation.references_field(self.model_name, self.new_name, app_label)
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)
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