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Hold the deprecated class reference in the metaclass

This commit is contained in:
Daniel Graña 2013-12-31 14:58:37 -02:00
parent 5af45689e4
commit 8c4e1db5fe
2 changed files with 18 additions and 15 deletions
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6
scrapy/tests/test_utils_deprecate.py
View File

@ -36,9 +36,9 @@ class WarnWhenSubclassedTest(unittest.TestCase):
assert issubclass(msg.category, MyWarning)
self.assertEqual(
str(msg.message),
"Base class scrapy.tests.test_utils_deprecate.Deprecated of "
"scrapy.tests.test_utils_deprecate.UserClass was deprecated. "
"Please inherit from scrapy.tests.test_utils_deprecate.NewName."
"scrapy.tests.test_utils_deprecate.UserClass inherits from "
"deprecated class scrapy.tests.test_utils_deprecate.Deprecated, "
"please inherit from scrapy.tests.test_utils_deprecate.NewName."
)
self.assertEqual(msg.lineno, inspect.getsourcelines(UserClass)[1])

27
scrapy/utils/deprecate.py
View File

@ -14,7 +14,8 @@ def attribute(obj, oldattr, newattr, version='0.12'):
def create_deprecated_class(name, new_class, clsdict=None,
warn_category=ScrapyDeprecationWarning,
warn_message=None):
warn_message="{cls} inherits from deprecated class {old}, "\
"please inherit from {new}."):
"""
Return a "deprecated" class that causes its subclasses to issue a warning.
Subclasses of ``new_class`` are considered subclasses of this class.
@ -38,16 +39,21 @@ def create_deprecated_class(name, new_class, clsdict=None,
OldName.
"""
deprecated = {}
class DeprecatedClass(type):
deprecated_class = None
def __new__(metacls, name, bases, clsdict_):
cls = super(DeprecatedClass, metacls).__new__(metacls, name, bases, clsdict_)
if metacls.deprecated_class is None:
metacls.deprecated_class = cls
return cls
def __init__(cls, name, bases, clsdict_):
if 'cls' in deprecated:
if warn_message is not None:
msg = warn_message
else:
msg = "Base class {0} of {1} was deprecated. Please inherit from {2}."\
.format(_clspath(deprecated['cls']), _clspath(cls), _clspath(new_class))
if cls is not cls.__class__.deprecated_class:
msg = warn_message.format(cls=_clspath(cls),
old=_clspath(cls.__class__.deprecated_class),
new=_clspath(new_class))
warnings.warn(msg, warn_category, stacklevel=2)
super(DeprecatedClass, cls).__init__(name, bases, clsdict_)
@ -66,10 +72,7 @@ def create_deprecated_class(name, new_class, clsdict=None,
candidates = {cls, new_class}
return any(c in candidates for c in mro)
clsdict = clsdict if clsdict is not None else {}
deprecated_cls = DeprecatedClass(name, (new_class,), clsdict)
deprecated['cls'] = deprecated_cls
deprecated_cls = DeprecatedClass(name, (new_class,), clsdict or {})
frm = inspect.stack()[1]
parent_module = inspect.getmodule(frm[0])
if parent_module is not None: