Commit d59f1993 authored by Loic Bistuer's avatar Loic Bistuer Committed by Tim Graham
Browse files

Made MigrationWriter look for a "deconstruct" attribute on functions. 

Refs #20978.
parent 5df8f749

django/db/migrations/writer.py

+23 −17
Original line number Diff line number Diff line
@@ -73,6 +73,26 @@ class MigrationWriter(object): 
                raise ImportError("Cannot open migrations module %s for app %s" % (migrations_module_name, self.migration.app_label))

        return os.path.join(basedir, self.filename)



    @classmethod

    def serialize_deconstructed(cls, path, args, kwargs):

        module, name = path.rsplit(".", 1)

        if module == "django.db.models":

            imports = set(["from django.db import models"])

            name = "models.%s" % name

        else:

            imports = set(["import %s" % module])

            name = path

        arg_strings = []

        for arg in args:

            arg_string, arg_imports = cls.serialize(arg)

            arg_strings.append(arg_string)

            imports.update(arg_imports)

        for kw, arg in kwargs.items():

            arg_string, arg_imports = cls.serialize(arg)

            imports.update(arg_imports)

            arg_strings.append("%s=%s" % (kw, arg_string))

        return "%s(%s)" % (name, ", ".join(arg_strings)), imports



    @classmethod

    def serialize(cls, value):

        """
@@ -119,23 +139,7 @@ class MigrationWriter(object): 
        # Django fields

        elif isinstance(value, models.Field):

            attr_name, path, args, kwargs = value.deconstruct()

            module, name = path.rsplit(".", 1)

            if module == "django.db.models":

                imports = set(["from django.db import models"])

                name = "models.%s" % name

            else:

                imports = set(["import %s" % module])

                name = path

            arg_strings = []

            for arg in args:

                arg_string, arg_imports = cls.serialize(arg)

                arg_strings.append(arg_string)

                imports.update(arg_imports)

            for kw, arg in kwargs.items():

                arg_string, arg_imports = cls.serialize(arg)

                imports.update(arg_imports)

                arg_strings.append("%s=%s" % (kw, arg_string))

            return "%s(%s)" % (name, ", ".join(arg_strings)), imports

            return cls.serialize_deconstructed(path, args, kwargs)

        # Functions

        elif isinstance(value, (types.FunctionType, types.BuiltinFunctionType)):

            # Special-cases, as these don't have im_class
@@ -152,6 +156,8 @@ class MigrationWriter(object): 
                klass = value.im_class

                module = klass.__module__

                return "%s.%s.%s" % (module, klass.__name__, value.__name__), set(["import %s" % module])

            elif hasattr(value, 'deconstruct'):

                return cls.serialize_deconstructed(*value.deconstruct())

            elif value.__name__ == '<lambda>':

                raise ValueError("Cannot serialize function: lambda")

            elif value.__module__ is None:

django/db/models/deletion.py

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ def SET(value): 
    else:

        def set_on_delete(collector, field, sub_objs, using):

            collector.add_field_update(field, value, sub_objs)

    set_on_delete.deconstruct = lambda: ('django.db.models.SET', (value,), {})

    return set_on_delete

tests/migrations/test_writer.py

+4 −0
Original line number Diff line number Diff line
@@ -63,6 +63,10 @@ class WriterTests(TestCase): 
        # Functions

        with six.assertRaisesRegex(self, ValueError, 'Cannot serialize function: lambda'):

            self.assertSerializedEqual(lambda x: 42)

        self.assertSerializedEqual(models.SET_NULL)

        string, imports = MigrationWriter.serialize(models.SET(42))

        self.assertEqual(string, 'models.SET(42)')

        self.serialize_round_trip(models.SET(42))

        # Datetime stuff

        self.assertSerializedEqual(datetime.datetime.utcnow())

        self.assertSerializedEqual(datetime.datetime.utcnow)