deprecation module


A warning class for deprecated methods


A warning class for methods to be removed

exception DeprecatedWarning(function, deprecated_in, removed_in, details='')[source]

Bases: DeprecationWarning

A warning class for deprecated methods

This is a specialization of the built-in DeprecationWarning, adding parameters that allow us to get information into the __str__ that ends up being sent through the warnings system. The attributes aren’t able to be retrieved after the warning gets raised and passed through the system as only the class–not the instance–and message are what gets preserved.

  • function – The function being deprecated.

  • deprecated_in – The version that function is deprecated in

  • removed_in – The version or specifying when function gets removed.

  • details – Optional details about the deprecation. Most often this will include directions on what to use instead of the now deprecated code.

exception UnsupportedWarning(function, deprecated_in, removed_in, details='')[source]

Bases: DeprecatedWarning

A warning class for methods to be removed

This is a subclass of DeprecatedWarning and is used to output a proper message about a function being unsupported. Additionally, the fail_if_not_removed decorator will handle this warning and cause any tests to fail if the system under test uses code that raises this warning.

deprecated(deprecated_in: str, removed_in=None, current_version=None, details='')[source]

Decorate a function to signify its deprecation

This function wraps a method that will soon be removed and does two things:

  • The docstring of the method will be modified to include a notice about deprecation, e.g., “Deprecated since 0.9.11. Use foo instead.”

  • Raises a DeprecatedWarning via the warnings module, which is a subclass of the built-in DeprecationWarning. Note that built-in DeprecationWarning are ignored by default, so for users to be informed of said warnings they will need to enable them–see the warnings module documentation for more details.

  • deprecated_in (str) – The version at which the decorated method is considered deprecated. This will usually be the next version to be released when the decorator is added.

  • removed_in – The version or when the decorated method will be removed. The default is None, specifying that the function is not currently planned to be removed.

  • current_version – The source of version information for the currently running code. This will usually be a __version__ attribute on your library. The default is None. When current_version=None the automation to determine if the wrapped function is actually in a period of deprecation or time for removal does not work, causing a DeprecatedWarning to be raised in all cases.

  • details – Extra details to be added to the method docstring and warning. For example, the details may point users to a replacement method, such as “Use the foo_bar method instead”. By default there are no details.


Decorate a test method to track removal of deprecated code

This decorator catches UnsupportedWarning warnings that occur during testing and causes unittests to fail, making it easier to keep track of when code should be removed.


AssertionError if an UnsupportedWarning is raised while running the test method.

message_location = 'bottom'

Location where the details are added to a deprecated docstring

When set to "bottom", the details are appended to the end. When set to "top", the details are inserted between the summary line and docstring contents.