deb-python-debtcollector/doc/source/user/usage.rst

Examples

Removing a class/classmethod/method/function

To signal to a user that a method (staticmethod, classmethod, or regular instance method) or a class or function is going to be removed at some point in the future the :py~debtcollector.removals.remove function/decorator can be used to achieve this in a non-destructive manner.

A basic example to do just this (on a method/function):

>>> from debtcollector import removals >>> import warnings >>> warnings.simplefilter('always') >>> class Car(object): ... @removals.remove ... def start(self): ... pass ... >>> c = Car() >>> c.start()

Expected output:

__main__:1: DeprecationWarning: Using function/method 'Car.start()' is deprecated

A basic example to do just this (on a class):

>>> from debtcollector import removals >>> import warnings >>> warnings.simplefilter('always') >>> @removals.removed_class("Pinto") ... class Pinto(object): ... pass ... >>> p = Pinto()

Expected output:

__main__:1: DeprecationWarning: Using class 'Pinto' (either directly or via inheritance) is deprecated

A basic example to do just this (on a classmethod):

>>> from debtcollector import removals >>> import warnings >>> warnings.simplefilter("once") >>> class OldAndBusted(object): ... @removals.remove ... @classmethod ... def fix_things(cls): ... pass ... >>> OldAndBusted.fix_things()

Expected output:

__main__:1: DeprecationWarning: Using function/method 'OldAndBusted.fix_things()' is deprecated

Removing a instance property

Use the :py~debtcollector.removals.removed_property decorator to signal that an attribute of a class is deprecated.

A basic example to do just this:

>>> import warnings >>> warnings.simplefilter("once") >>> from debtcollector import removals >>> class OldAndBusted(object): ... @removals.removed_property ... def thing(self): ... return 'old-and-busted' ... @thing.setter ... def thing(self, value): ... pass ... @thing.deleter ... def thing(self): ... pass ... >>> o = OldAndBusted() >>> o.thing 'old-and-busted' >>> o.thing = '2' >>> del o.thing

__main__:1: DeprecationWarning: Reading the 'thing' property is deprecated __main__:1: DeprecationWarning: Setting the 'thing' property is deprecated __main__:1: DeprecationWarning: Deleting the 'thing' property is deprecated

Removing a keyword argument

A basic example to do just this (on a classmethod):

>>> import warnings >>> warnings.simplefilter("once") >>> from debtcollector import removals >>> class OldAndBusted(object): ... @removals.removed_kwarg('resp', message="Please use 'response' instead") ... @classmethod ... def factory(cls, resp=None, response=None): ... response = resp or response ... return response ... >>> OldAndBusted.factory(resp='super-duper') 'super-duper'

__main__:1: DeprecationWarning: Using the 'resp' argument is deprecated: Please use 'response' instead

A basic example to do just this (on a __init__ method):

>>> import warnings >>> warnings.simplefilter("once") >>> from debtcollector import removals >>> class OldAndBusted(object): ... @removals.removed_kwarg('bleep') ... def __init__(self, bleep=None): ... self.bloop = bleep ... >>> o = OldAndBusted(bleep=2)

__main__:1: DeprecationWarning: Using the 'bleep' argument is deprecated

Changing the default value of a keyword argument

A basic example to do just this:

>>> import warnings >>> warnings.simplefilter("once") >>> from debtcollector import updating >>> class OldAndBusted(object): ... ip = '127.0.0.1' ... @updating.updated_kwarg_default_value('type', 'http', 'https') ... def url(self, type='http'): ... response = '%s://%s' % (type, self.ip) ... return response ... >>> OldAndBusted().url() 'http://127.0.0.1'

__main__:1: FutureWarning: The http argument is changing its default value to https, please update the code to explicitly set http as the value

A basic classmethod example.

Note

the @classmethod decorator is before the debtcollector one

>>> import warnings >>> warnings.simplefilter("once") >>> from debtcollector import updating >>> class OldAndBusted(object): ... ip = '127.0.0.1' ... @classmethod ... @updating.updated_kwarg_default_value('type', 'http', 'https') ... def url(cls, type='http'): ... response = '%s://%s' % (type, cls.ip) ... return response ... >>> OldAndBusted.url() 'http://127.0.0.1'

__main__:1: FutureWarning: The http argument is changing its default value to https, please update the code to explicitly set http as the value

Moving a function

To change the name or location of a regular function use the :py~debtcollector.moves.moved_function function:

>>> from debtcollector import moves >>> import warnings >>> warnings.simplefilter('always') >>> def new_thing(): ... return "new thing" ... >>> old_thing = moves.moved_function(new_thing, 'old_thing', __name__) >>> new_thing() 'new thing' >>> old_thing() 'new thing'

Expected output:

__main__:1: DeprecationWarning: Function '__main__.old_thing()' has moved to '__main__.new_thing()'

Moving a method

To move a instance method from an existing one to a new one the :py~debtcollector.moves.moved_method function/decorator can be used to achieve this in a non-destructive manner.

A basic example to do just this:

>>> from debtcollector import moves >>> import warnings >>> warnings.simplefilter('always') >>> class Cat(object): ... @moves.moved_method('meow') ... def mewow(self): ... return self.meow() ... def meow(self): ... return 'kitty' ... >>> c = Cat() >>> c.mewow() 'kitty' >>> c.meow() 'kitty'

Expected output:

__main__:1: DeprecationWarning: Method 'Cat.mewow()' has moved to 'Cat.meow()'

Moving a property

To move a instance property from an existing one to a new one the :py~debtcollector.moves.moved_property function/decorator can be used to achieve this in a non-destructive manner.

A basic example to do just this:

>>> from debtcollector import moves >>> import warnings >>> warnings.simplefilter('always') >>> class Dog(object): ... @property ... @moves.moved_property('bark') ... def burk(self): ... return self.bark ... @property ... def bark(self): ... return 'woof' ... >>> d = Dog() >>> d.burk 'woof' >>> d.bark 'woof'

Expected output:

__main__:1: DeprecationWarning: Property 'Dog.burk' has moved to 'Dog.bark'

Moving a class

To move a class from an existing one to a new one the :py~debtcollector.moves.moved_class type generator function can be used to achieve this in a non-destructive manner.

A basic example to do just this:

>>> from debtcollector import moves >>> import warnings >>> warnings.simplefilter('always') >>> class WizBang(object): ... pass ... >>> OldWizBang = moves.moved_class(WizBang, 'OldWizBang', __name__) >>> a = OldWizBang() >>> b = WizBang()

Expected output:

__main__:1: DeprecationWarning: Class '__main__.OldWizBang' has moved to '__main__.WizBang'

Renaming a keyword argument

To notify the user when a keyword argument has been replaced with a new and improved keyword argument and the user is still using the old keyword argument the :py~debtcollector.renames.renamed_kwarg function/decorator can be used to achieve this in a non-destructive manner.

A basic example to do just this:

>>> from debtcollector import renames >>> import warnings >>> warnings.simplefilter('always') >>> @renames.renamed_kwarg('snizzle', 'nizzle') ... def do_the_deed(snizzle=True, nizzle=True): ... return (snizzle, nizzle) ... >>> do_the_deed() (True, True) >>> do_the_deed(snizzle=False) (False, True) >>> do_the_deed(nizzle=False) (True, False)

Expected output:

__main__:1: DeprecationWarning: Using the 'snizzle' argument is deprecated, please use the 'nizzle' argument instead

Further customizing the emitted messages

It is typically useful to tell the user when a deprecation has started and when the deprecated item will be officially removed (deleted or other). To enable this all the currently provided functions this library provides take a message, version and removal_version keyword arguments. These are used in forming the message that is shown to the user when they trigger the deprecated activity.

A basic example to do just this:

>>> from debtcollector import renames >>> import warnings >>> warnings.simplefilter('always') >>> @renames.renamed_kwarg('snizzle', 'nizzle', version="0.5", removal_version="0.7") ... def do_the_deed(snizzle=True, nizzle=True): ... pass ... >>> do_the_deed(snizzle=False)

Expected output:

__main__:1: DeprecationWarning: Using the 'snizzle' argument is deprecated in version '0.5' and will be removed in version '0.7', please use the 'nizzle' argument instead

If the removal_version is unknown the special character ? can be used instead (to denote that the deprecated activity will be removed sometime in the future).

A basic example to do just this:

>>> from debtcollector import renames >>> import warnings >>> warnings.simplefilter('always') >>> @renames.renamed_kwarg('snizzle', 'nizzle', version="0.5", removal_version="?") ... def do_the_deed(snizzle=True, nizzle=True): ... pass ... >>> do_the_deed(snizzle=False)

Expected output:

__main__:1: DeprecationWarning: Using the 'snizzle' argument is deprecated in version '0.5' and will be removed in a future version, please use the 'nizzle' argument instead

To further customize the message (with a special postfix) the message keyword argument can be provided.

A basic example to do just this:

>>> from debtcollector import renames >>> import warnings >>> warnings.simplefilter('always') >>> @renames.renamed_kwarg('snizzle', 'nizzle', message="Pretty please stop using it") ... def do_the_deed(snizzle=True, nizzle=True): ... pass ... >>> do_the_deed(snizzle=False)

Expected output:

__main__:1: DeprecationWarning: Using the 'snizzle' argument is deprecated, please use the 'nizzle' argument instead: Pretty please stop using it

Deprecating anything else

For use-cases which do not fit the above decorators, properties other provided functionality the final option is to use debtcollectors the :py~debtcollector.deprecate function to make your own messages (using the message building logic that debtcollector uses itself).

A basic example to do just this:

>>> import warnings >>> warnings.simplefilter("always") >>> import debtcollector >>> debtcollector.deprecate("This is no longer supported", version="1.0")

__main__:1: DeprecationWarning: This is no longer supported in version '1.0'