| Backward Compatibility |
| ====================== |
| |
| .. currentmodule:: attr |
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| ``attrs`` has a very strong backward compatibility policy that is inspired by the policy of the `Twisted framework <https://twistedmatrix.com/trac/wiki/CompatibilityPolicy>`_. |
| |
| Put simply, you shouldn't ever be afraid to upgrade ``attrs`` if you're only using its public APIs. |
| If there will ever be a need to break compatibility, it will be announced in the :doc:`changelog` and raise a ``DeprecationWarning`` for a year (if possible) before it's finally really broken. |
| |
| |
| .. _exemption: |
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| .. warning:: |
| |
| The structure of the :class:`attr.Attribute` class is exempt from this rule. |
| It *will* change in the future, but since it should be considered read-only, that shouldn't matter. |
| |
| However if you intend to build extensions on top of ``attrs`` you have to anticipate that. |
