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Fixed #27768 -- Allowed migration optimization of CreateModel order. 

Thanks Ed Morley from Mozilla for the tests.
This commit is contained in:
Simon Charette 2017-01-30 13:43:20 -05:00 committed by Tim Graham
parent d3a935f01f
commit a97845a823
5 changed files with 119 additions and 43 deletions
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10
django/db/migrations/operations/base.py
View File

@ -80,6 +80,16 @@ class Operation:
"""
return "%s: %s" % (self.__class__.__name__, self._constructor_args)
def model_to_key(self, model):
"""
Take either a model class or an 'app_label.ModelName' string and return
(app_label, model_name).
"""
if isinstance(model, str):
return tuple(model.lower().split('.', 1))
else:
return model._meta.app_label, model._meta.model_name
def references_model(self, name, app_label=None):
"""
Return True if there is a chance this operation references the given

19
django/db/migrations/operations/fields.py
View File

@ -26,10 +26,25 @@ class FieldOperation(Operation):
return self.is_same_model_operation(operation) and self.name_lower == operation.name_lower
def references_model(self, name, app_label=None):
return name.lower() == self.model_name_lower
name_lower = name.lower()
if name_lower == self.model_name_lower:
return True
field = getattr(self, 'field', None)
if field and field.remote_field:
remote_app_label, remote_model_name = self.model_to_key(field.remote_field.model)
if (remote_model_name == name_lower and app_label is None or
not remote_app_label or remote_app_label == app_label):
return True
through = getattr(field.remote_field, 'through', None)
if through and self.model_to_key(through) == (app_label, name_lower):
through_app_label, through_model_name = self.model_to_key(through)
if (through_model_name == name_lower and app_label is None or
not through_app_label or through_app_label == app_label):
return True
return False
def references_field(self, model_name, name, app_label=None):
return self.references_model(model_name) and name.lower() == self.name_lower
return self.references_model(model_name, app_label) and name.lower() == self.name_lower
def reduce(self, operation, in_between, app_label=None):
return (

28
django/db/migrations/operations/models.py
View File

@ -115,21 +115,11 @@ class CreateModel(ModelOperation):
# Now go over all the models and check against them
for model in models_to_check:
model_app_label, model_name = self.model_to_key(model)
if model_name.lower() == name_lower:
if app_label is None or not model_app_label or model_app_label == app_label:
return True
if (model_name == name_lower and app_label is None or
not model_app_label or model_app_label == app_label):
return True
return False
def model_to_key(self, model):
"""
Take either a model class or an "app_label.ModelName" string
and return (app_label, object_name).
"""
if isinstance(model, str):
return model.split(".", 1)
else:
return model._meta.app_label, model._meta.object_name
def reduce(self, operation, in_between, app_label=None):
if (isinstance(operation, DeleteModel) and
self.name_lower == operation.name_lower and
@ -157,18 +147,6 @@ class CreateModel(ModelOperation):
]
elif isinstance(operation, FieldOperation) and self.name_lower == operation.model_name_lower:
if isinstance(operation, AddField):
# Don't allow optimizations of FKs through models they reference
if hasattr(operation.field, "remote_field") and operation.field.remote_field:
for between in in_between:
# Check that it doesn't point to the model
app_label, object_name = self.model_to_key(operation.field.remote_field.model)
if between.references_model(object_name, app_label):
return False
# Check that it's not through the model
if getattr(operation.field.remote_field, "through", None):
app_label, object_name = self.model_to_key(operation.field.remote_field.through)
if between.references_model(object_name, app_label):
return False
return [
CreateModel(
self.name,

18
tests/migrations/test_autodetector.py
View File

@ -1150,10 +1150,9 @@ class AutodetectorTests(TestCase):
changes = self.get_changes([], [self.author_with_publisher, self.publisher])
# Right number/type of migrations?
self.assertNumberMigrations(changes, 'testapp', 1)
self.assertOperationTypes(changes, 'testapp', 0, ["CreateModel", "CreateModel", "AddField"])
self.assertOperationAttributes(changes, "testapp", 0, 0, name="Author")
self.assertOperationAttributes(changes, "testapp", 0, 1, name="Publisher")
self.assertOperationAttributes(changes, "testapp", 0, 2, name="publisher")
self.assertOperationTypes(changes, 'testapp', 0, ["CreateModel", "CreateModel"])
self.assertOperationAttributes(changes, "testapp", 0, 0, name="Publisher")
self.assertOperationAttributes(changes, "testapp", 0, 1, name="Author")
self.assertMigrationDependencies(changes, 'testapp', 0, [])
def test_circular_fk_dependency(self):
@ -1907,13 +1906,12 @@ class AutodetectorTests(TestCase):
# Right number/type of migrations?
self.assertNumberMigrations(changes, "testapp", 1)
self.assertOperationTypes(changes, "testapp", 0, [
"CreateModel", "CreateModel", "CreateModel", "AddField", "AddField"
'CreateModel', 'CreateModel', 'CreateModel', 'AddField',
])
self.assertOperationAttributes(changes, 'testapp', 0, 0, name="Author")
self.assertOperationAttributes(changes, 'testapp', 0, 1, name="Contract")
self.assertOperationAttributes(changes, 'testapp', 0, 2, name="Publisher")
self.assertOperationAttributes(changes, 'testapp', 0, 3, model_name='contract', name='publisher')
self.assertOperationAttributes(changes, 'testapp', 0, 4, model_name='author', name='publishers')
self.assertOperationAttributes(changes, 'testapp', 0, 0, name='Author')
self.assertOperationAttributes(changes, 'testapp', 0, 1, name='Publisher')
self.assertOperationAttributes(changes, 'testapp', 0, 2, name='Contract')
self.assertOperationAttributes(changes, 'testapp', 0, 3, model_name='author', name='publishers')
def test_many_to_many_removed_before_through_model(self):
"""

87
tests/migrations/test_optimizer.py
View File

@ -300,16 +300,91 @@ class OptimizerTests(SimpleTestCase):
],
)
def test_create_model_add_field_not_through_fk(self):
def test_create_model_reordering(self):
"""
AddField should NOT optimize into CreateModel if it's an FK to a model
that's between them.
AddField optimizes into CreateModel if it's a FK to a model that's
between them (and there's no FK in the other direction), by changing
the order of the CreateModel operations.
"""
self.assertOptimizesTo(
[
migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
migrations.CreateModel('Link', [('url', models.TextField())]),
migrations.AddField('Foo', 'link', models.ForeignKey('migrations.Link', models.CASCADE)),
],
[
migrations.CreateModel('Link', [('url', models.TextField())]),
migrations.CreateModel('Foo', [
('name', models.CharField(max_length=255)),
('link', models.ForeignKey('migrations.Link', models.CASCADE))
]),
],
)
def test_create_model_reordering_circular_fk(self):
"""
CreateModel reordering behavior doesn't result in an infinite loop if
there are FKs in both directions.
"""
self.assertOptimizesTo(
[
migrations.CreateModel('Bar', [('url', models.TextField())]),
migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
migrations.AddField('Bar', 'foo_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
migrations.AddField('Foo', 'bar_fk', models.ForeignKey('migrations.Bar', models.CASCADE)),
],
[
migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
migrations.CreateModel('Bar', [
('url', models.TextField()),
('foo_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
]),
migrations.AddField('Foo', 'bar_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
],
)
def test_create_model_no_reordering_for_unrelated_fk(self):
"""
CreateModel order remains unchanged if the later AddField operation
isn't a FK between them.
"""
self.assertDoesNotOptimize(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Link", [("url", models.TextField())]),
migrations.AddField("Foo", "link", models.ForeignKey("migrations.Link", models.CASCADE)),
migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
migrations.CreateModel('Link', [('url', models.TextField())]),
migrations.AddField('Other', 'link', models.ForeignKey('migrations.Link', models.CASCADE)),
],
)
def test_create_model_no_reordering_of_inherited_model(self):
"""
A CreateModel that inherits from another isn't reordered to avoid
moving it earlier than its parent CreateModel operation.
"""
self.assertOptimizesTo(
[
migrations.CreateModel('Other', [('foo', models.CharField(max_length=255))]),
migrations.CreateModel('ParentModel', [('bar', models.CharField(max_length=255))]),
migrations.CreateModel(
'ChildModel',
[('baz', models.CharField(max_length=255))],
bases=('migrations.parentmodel',),
),
migrations.AddField('Other', 'fk', models.ForeignKey('migrations.ChildModel', models.CASCADE)),
],
[
migrations.CreateModel('ParentModel', [('bar', models.CharField(max_length=255))]),
migrations.CreateModel(
'ChildModel',
[('baz', models.CharField(max_length=255))],
bases=('migrations.parentmodel',),
),
migrations.CreateModel(
'Other', [
('foo', models.CharField(max_length=255)),
('fk', models.ForeignKey('migrations.ChildModel', models.CASCADE)),
]
),
],
)