python-chess v0.22.0

Changes:

* `len(board.legal_moves)` **replaced by** `board.legal_moves.count()`.
  Previously `list(board.legal_moves)` was generating moves twice, resulting in
  a considerable slowdown. Thanks to Martin C. Doege for reporting.
* XBoard: `offer_draw` renamed to `draw`.

New features:

* XBoard: Added `DrawHandler`.

python-chess v0.21.2

Changes:

* `chess.svg` is now fully SVG Tiny 1.2 compatible.

python-chess v0.21.1

Bugfixes:

* `Board.set_piece_at()` no longer shadows optional `promoted`
  argument from `BaseBoard`.
* Fixed `ThreeCheckBoard.is_irreversible()` and
  `ThreeCheckBoard._transposition_key()`.

New features:

* Added `Game.without_tag_roster()`. `chess.pgn.StringExporter()` can now
  handle games without any headers.
* XBoard: `white`, `black`, `random`, `nps`, `optim`, `undo`, `remove`. Thanks
  to Manik Charan.

Changes:

* Documentation fixes and tweaks by Boštjan Mejak.
* Changed unicode character for empty squares in `Board.unicode()`.

python-chess v0.21.0

Bugfixes:

* `Board.set_piece_at()` no longer shadows optional `promoted`
  argument from `BaseBoard`.
* Fixed `ThreeCheckBoard.is_irreversible()` and
  `ThreeCheckBoard._transposition_key()`.

Changes:

* `chess.pgn.read_pgn()` **no longer adds the default 7 tag roster.**
  For example `game.headers["White"]` may now raise `KeyError` instead of
  providing the default value `?`. Use `game.headers.get("White", "?")` for
  equivalent behavior.
* Documentation fixes and tweaks by Boštjan Mejak.
* Changed unicode character for empty squares in `Board.unicode()`.

New features:

* XBoard: `white`, `black`, `random`, `nps`, `optim`, `undo`, `remove`. Thanks
  to Manik Charan.

python-chess v0.20.1

Bugfixes:

* Fix arrow positioning on SVG boards.
* Documentation fixes and improvements, making most doctests runnable.

python-chess v0.20.0

Bugfixes:

* Some XBoard commands were not returning futures.
* Support semicolon comments in PGNs.

Changes:

* Changed FEN and EPD formatting options. It is now possible to include en
  passant squares in FEN and X-FEN style, or to include only strictly relevant
  en passant squares.
* Relax en passant square validation in `Board.set_fen()`.
* Ensure `is_en_passant()`, `is_capture()`, `is_zeroing()` and
  `is_irreversible()` strictly return bools.
* Accept `Z0` as a null move in PGNs.

New features:

* XBoard: Add `memory`, `core`, `stop` and `movenow` commands.
  Abstract `post`/`nopost`. Initial `FeatureMap` support. Support `usermove`.
* Added `Board.has_pseudo_legal_en_passant()`.
* Added `Board.piece_map()`.
* Added `SquareSet.carry_rippler()`.
* Factored out some (unstable) low level APIs: `BB_CORNERS`,
  `_carry_rippler()`, `_edges()`.

python-chess v0.19.0

New features:

* **Experimental XBoard engine support.** Thanks to Manik Charan and
  Cash Costello. Expect breaking changes in future releases.
* Added an undocumented `chess.polyglot.ZobristHasher` to make Zobrist hashing
  easier to extend.

Bugfixes:

* Merely pseudo-legal en passant does no longer count for repetitions.
* Fixed repetition detection in Three-Check and Crazyhouse. (Previously
  check counters and pockets were ignored.)
* Checking moves in Three-Check are now considered as irreversible by
  `ThreeCheckBoard.is_irreversible()`.
* `chess.Move.from_uci("")` was raising `IndexError` instead of `ValueError`.
  Thanks Jonny Balls.

Changes:

* `chess.syzygy.Tablebases` constructor no longer supports directly opening
  a directory. Use `chess.syzygy.open_tablebases()`.
* `chess.gaviota.PythonTablebases` and `NativeTablebases` constructors
  no longer support directly opening a directory.
  Use `chess.gaviota.open_tablebases()`.
* `chess.Board` instances are now compared by the position they represent,
  not by exact match of the internal data structures (or even move history).
* Relaxed castling right validation in Chess960: Kings/rooks of opposing sites
  are no longer required to be on the same file.
* Removed misnamed `Piece.__unicode__()` and `BaseBoard.__unicode__()`. Use
  `Piece.unicode_symbol()` and `BaseBoard.unicode()` instead.
* Changed `chess.SquareSet.__repr__()`.
* Support `[Variant "normal"]` in PGNs.
* `pip install python-chess[engine]` instead of `python-chess[uci]` (since
  the extra dependencies are required for both UCI and XBoard engines).
* Mixed documentation fixes and improvements.

python-chess v0.18.4

Changes:

* Support `[Variant "fischerrandom"]` in PGNs for Cutechess compability.
  Thanks to Steve Maughan for reporting.

python-chess v0.18.3

Bugfixes:

* `chess.gaviota.NativeTablebases.get_dtm()` and `get_wdl()` were missing.

python-chess v0.18.2

Bugfixes:

* Fixed castling in atomic chess when there is a rank attack.
* The halfmove clock in Crazyhouse is no longer incremented unconditionally.
  `CrazyhouseBoard.is_zeroing(move)` now considers pawn moves and captures as
  zeroing. Added `Board.is_irreversible(move)` that can be used instead.
* Fixed an inconsistency where the `chess.pgn` tokenizer accepts long algebraic
  notation but `Board.parse_san()` did not.

Changes:

* Added more NAG constants in `chess.pgn`.