This release teaches :class:`~hypothesis.stateful.RuleBasedStateMachine` to avoid checking :func:`~hypothesis.stateful.invariant`\ s until all :func:`~hypothesis.stateful.initialize` rules have been run. You can enable checking of specific invariants for incompletely initialized machines by using ``invariant(check_during_init=True)`` (:issue:`2868`).
In previous versions, it was possible if awkward to implement this behaviour using :func:`~hypothesis.stateful.precondition` and an auxiliary variable.
6.6.1
------------------
This patch improves the error message when :func:`~hypothesis.strategies.from_type` fails to resolve a forward-reference inside a :class:`python:typing.Type` such as ``Type["int"]`` (:issue:`2565`).
6.6.0
------------------
This release makes it an explicit error to apply :func:`~hypothesis.stateful.invariant` to a :func:`~hypothesis.stateful.rule` or :func:`~hypothesis.stateful.initialize` rule in :doc:`stateful testing <stateful>`. Such a combination had unclear semantics, especially in combination with :func:`~hypothesis.stateful.precondition`, and was never meant to be allowed (:issue:`2681`).
6.5.0
------------------
This release adds :ref:`the explain phase <phases>`, in which Hypothesis attempts to explain *why* your test failed by pointing to suspicious lines of code (i.e. those which were always, and only, run on failing inputs). We plan to include "generalising" failing examples in this phase in a future release (:issue:`2192`).
6.4.3
------------------
This patch fixes :issue:`2794`, where nesting :func:`~hypothesis.strategies.deferred` strategies within :func:`~hypothesis.strategies.recursive` strategies could trigger an internal assertion. While it was always possible to get the same results from a more sensible strategy, the convoluted form now works too.
6.4.2
------------------
This patch fixes several problems with ``mypy`` when `--no-implicit-reexport <https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-no-implicit-reexport>`_ was activated in user projects.
Thanks to Nikita Sobolev for fixing :issue:`2884`!