1.1.0 (2024-10-31)
==================

No significant changes.


1.1.0b1 (2024-10-01)
====================

Features
--------

- Declare supported Python version support ">= 3.7" in dist meta  `#129 <https://github.com/sarugaku/resolvelib/issues/129>`_
  
- Improve exception chaining when ResolutionImpossible raises during backjumping  `#133 <https://github.com/sarugaku/resolvelib/issues/133>`_
  
- Switch from pyi files to modern annotations based type hinting  `#135 <https://github.com/sarugaku/resolvelib/issues/135>`_
  
- In tests the commentjson test dependency with re.sub  `#141 <https://github.com/sarugaku/resolvelib/issues/141>`_
  
- Deduplicate failure causes to save memory and reduce backtracking overhead  `#143 <https://github.com/sarugaku/resolvelib/issues/143>`_
  
- New `narrow_requirement_selection` provider method giving option for
  providers to reduce the number of times sort key `get_preference` is
  called in long running backtrack  `#145 <https://github.com/sarugaku/resolvelib/issues/145>`_
  
- Run tests against Python 3.12, 3.13, and use latest version of CI dependencies  `#153 <https://github.com/sarugaku/resolvelib/issues/153>`_
  
- Update py2ndex script to use metadata files, skip 404, and support PEP 723  `#156 <https://github.com/sarugaku/resolvelib/issues/156>`_
  
- Replace setuptools.cfg and mypy.ini with pyproject.toml  `#157 <https://github.com/sarugaku/resolvelib/issues/157>`_
  
- Add tests type "unvisited" to functional Python tests to ensure backjumping
  is correctly skipping candidates  `#158 <https://github.com/sarugaku/resolvelib/issues/158>`_
  
- Switch from flake8 to ruff for linting  `#160 <https://github.com/sarugaku/resolvelib/issues/160>`_
  
- Enable automatic TYPE_CHECK guarding for imports only used for type hinting
  via ruff rules TCH and FA  `#166 <https://github.com/sarugaku/resolvelib/issues/166>`_
  

Bug Fixes
---------

- Fix example reporter_demo `get_preference` method which requires arg `backtrack_causes`  `#136 <https://github.com/sarugaku/resolvelib/issues/136>`_
  
- Clarify the docstrings for `providers.py`  `#138 <https://github.com/sarugaku/resolvelib/issues/138>`_
  
- Pin Black version for linting to prevent CI failures  `#150 <https://github.com/sarugaku/resolvelib/issues/150>`_
  
- In unexpected situation where broken_state.mapping is empty, stop backtracking,
  and continue resolution (rather than throwing ResolutionImpossible)  `#152 <https://github.com/sarugaku/resolvelib/issues/152>`_
  
- During backtracking check if the current broken state is an incompatible dependency,
  if not stop backtracking and continue resolution.  `#155 <https://github.com/sarugaku/resolvelib/issues/155>`_
  
- Separate AbstractResolver and Resolver into different modules  `#162 <https://github.com/sarugaku/resolvelib/issues/162>`_
  
- Separate resolvers into different modules  `#163 <https://github.com/sarugaku/resolvelib/issues/163>`_
  
- Export criterion in resolvers to keep compatibility  `#164 <https://github.com/sarugaku/resolvelib/issues/164>`_
  
- Enable isorting via ruff  `#165 <https://github.com/sarugaku/resolvelib/issues/165>`_
  
1.0.1 (2023-03-09)
==================

Bug Fixes
---------

- Fix calls to opaque objects and use provider interface calls instead.  `#126 <https://github.com/sarugaku/resolvelib/issues/126>`_


1.0.0 (2023-03-08)
==================

Features
--------

- Implement backjumping to significantly speed up the resolution process by skipping over irrelevant parts of the resolution search space.  `#113 <https://github.com/sarugaku/resolvelib/issues/113>`_


0.9.0 (2022-11-17)
==================

Features
--------

- A new reporter hook ``rejecting_candidate`` is added, replacing ``backtracking``.
  The hook is called every time the resolver rejects a conflicting candidate before
  trying out the next one in line.  `#101 <https://github.com/sarugaku/resolvelib/issues/101>`_
  

Bug Fixes
---------

- Some valid states that were previously rejected are now accepted. This affects
  states where multiple candidates for the same dependency conflict with each
  other. The ``information`` argument passed to
  ``AbstractProvider.get_preference`` may now contain empty iterators. This has
  always been allowed by the method definition but it was previously not possible
  in practice.  `#91 <https://github.com/sarugaku/resolvelib/issues/91>`_


0.8.1 (2021-10-12)
==================

Features
--------

- A new reporter hook ``resolving_conflicts`` is added. The resolver triggers
  this hook when it detects conflicts in the dependency tree, and before it
  attempts to fix them. The hook accepts one single argument ``causes``, which
  is a list of ``(requirement, parent)`` 2-tuples that represents all the
  edges that lead to the detected conflicts.  `#81 <https://github.com/sarugaku/resolvelib/issues/81>`_


0.8.0 (2021-10-08)
==================

Features
--------

- Add ``backtrack_causes`` to ``get_preference``, which contains information
  about the requirements involved in the most recent backtrack. This allows
  the provider to utilise this information to tweak the ordering as well as
  for recording/reporting conflicts.


0.7.1 (2021-06-22)
==================

Bug Fixes
---------

- When merging a candidate's dependencies, make sure the merge target is
  up-to-date within the loop, so the merge does not lose information when a
  candidate returns multiple dependency specifications under one identifier
  (e.g. specifyiung two dependencies ``a>1`` and ``a<2``, instead of one single
  ``a>1,<2`` dependency).  `#80 <https://github.com/sarugaku/resolvelib/issues/80>`_


0.7.0 (2021-04-13)
==================

Features
--------

- Redesign ``get_preference()`` to include resolution state on dependencies
  other than the currently working one, to allow the provider to better take
  account of the global resolver knowledge and determine the best strategy. The
  provider now can, for example, correctly calculate how far a dependency is
  from the root node in the graph.  `#74 <https://github.com/sarugaku/resolvelib/issues/74>`_


0.6.0 (2021-04-04)
==================

Features
--------

- A new argument ``incompatibilities`` is now passed to the ``find_matches()``
  hook, which the provider must use to exclude matches from the return value.  `#68 <https://github.com/sarugaku/resolvelib/issues/68>`_

- Redesign ``find_matches()`` to include resolution state on dependencies other
  than the currently working one, to handle usages that need to return candidates
  based on non-local states. One such example is PEP 508 direct URLs specified
  on a package, which need to be available to the same package specified with
  extras (which would have a different identifier).  `#74 <https://github.com/sarugaku/resolvelib/issues/74>`_


Bug Fixes
---------

- The resolver no longer relies on implicit candidate equality to detect
  incompatibilities. This is done by an additional ``find_matches()`` argument;
  see the *Features* section to learn more.  `#68 <https://github.com/sarugaku/resolvelib/issues/68>`_


0.5.5 (2021-03-09)
==================

Features
--------

- Provide type stubs for most classes.  `#72 <https://github.com/sarugaku/resolvelib/issues/72>`_


0.5.4 (2020-12-27)
==================

No significant changes.


0.5.3 (2020-11-27)
==================

Bug Fixes
---------

- Fix a state management bug that causes the resolver to enter an infinite loop
  in certain backtracking cases.  `#62 <https://github.com/sarugaku/resolvelib/issues/62>`_


0.5.2 (2020-11-04)
==================

Bug Fixes
---------

- Fix a performance regression if ``find_matches()`` returns a non-built-in sequence instance.


0.5.1 (2020-10-22)
==================

Features
--------

- ``find_matches()`` now may return a ``Callable[[], Iterator[Candidate]]`` to avoid needing to provide all candidates eagerly for the resolver. This improves performance when fetching candidates is costly, but not always required.  `#57 <https://github.com/sarugaku/resolvelib/issues/57>`_


0.4.0 (2020-04-30)
==================

Features
--------

- Add ``parent`` argument to the ``add_requirement()`` reporter hook.  `#46 <https://github.com/sarugaku/resolvelib/issues/46>`_

- Redesign ``find_matches()`` to support a requirement "adding" candidates to the set, and nudge the provider away from implementing ``find_matches()`` and ``is_satisfied_by()`` with incorrect set properties.  `#49 <https://github.com/sarugaku/resolvelib/issues/49>`_


0.3.0 (2020-04-11)
==================

Features
--------

- Provide both the requirements and their parents as exceptiondata for the ``ResolutionImpossible`` exception, via a ``causes`` attribute that replaces the previous ``requirements`` attribute.  `#42 <https://github.com/sarugaku/resolvelib/issues/42>`_


Bug Fixes
---------

- Make resolver backtrack when none of the candidates requested for a package are able to resolve due to them requesting unworkable requirements, or a package has no candidates at all. Previously the resolver would give up on the spot.  `#18 <https://github.com/sarugaku/resolvelib/issues/18>`_

- Ensure the result returned by the resolver only contains candidates that are actually needed. This is done by tracing the graph after resolution completes, snipping nodes that don’t have a route to the root.  `#4 <https://github.com/sarugaku/resolvelib/issues/4>`_


0.2.2 (2018-09-03)
==================

Features
--------

- Remove reporting callbacks `adding_requirements`, `adding_candidate`, and `replacing_candidate` added in 0.2.1. These are not useful, and it’s better to remove them while we can.  `#6 <https://github.com/sarugaku/resolvelib/issues/6>`_


0.2.1 (2018-08-21)
==================

Features
--------

- Add new reporting callbacks `adding_requirements`, `adding_candidate`, and `replacing_candidate` to report progress in requirement pinning.  `#2 <https://github.com/sarugaku/resolvelib/issues/2>`_


Bug Fixes
---------

- Fix missing edges in the resolved dependency graph caused by incorrectly copying stale constraint and parent-child information.  `#5 <https://github.com/sarugaku/resolvelib/issues/5>`_


0.2.0 (2018-08-07)
==================

* ``Resolver.resolve()`` now returns a `namedtuple` with public attributes, instead of an internal `Resolution` object.
* Update trove classifiers on PyPI to better reflect the project's intentions.
