Drop Python 2.6 support (niklasf#126)

niklasf · niklasf · commit ad9ce52b9165 · 2017-11-17T17:26:48.000+01:00
First introduced 2 years ago in af72d5a, when it was already 2 years dead, but easy to support. Now dependencies dropped support and I don't want to add further workarounds.
diff --git a/.travis.yml b/.travis.yml
@@ -2,7 +2,6 @@ language: python
 dist: trusty
 sudo: false
 python:
- - "2.6"
  - "2.7"
  - "3.3"
  - "3.4"
diff --git a/README.rst b/README.rst
@@ -67,7 +67,7 @@ python-chess:
 Features
 --------
 
-* Supports Python 2.6+, Python 3.3+ and PyPy.
+* Supports Python 2.7, Python 3.3+ and PyPy.
 
 * IPython/Jupyter Notebook integration.
   `SVG rendering docs <https://python-chess.readthedocs.io/en/latest/svg.html>`_.
diff --git a/chess/__init__.py b/chess/__init__.py
@@ -28,15 +28,11 @@
 
 __version__ = "0.21.2"
 
+import collections
 import copy
 import re
 import itertools
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
-
 COLORS = [WHITE, BLACK] = [True, False]
 COLOR_NAMES = ["black", "white"]
 
@@ -165,58 +161,23 @@ def square_mirror(square):
 BB_BACKRANKS = BB_RANK_1 | BB_RANK_8
 
 
-try:
-    # Added in Python 2.7 and 3.1, respectively.
-    int.bit_length
-except AttributeError:
-    def _lsb_table():
-        table = [0 for _ in range(64)]
-        for square, bb in enumerate(BB_SQUARES):
-            index = (((bb ^ (bb - 1)) * 0x3f79d71b4cb0a89) & 0xffffffffffffffff) >> 58
-            table[index] = square
-        return table
-
-    def lsb(bb, _table=_lsb_table()):
-        return _table[(((bb ^ (bb - 1)) * 0x3f79d71b4cb0a89) & 0xffffffffffffffff) >> 58]
-
-    def scan_forward(bb, _bin=bin, _len=len):
-        string = _bin(bb)
-        l = _len(string)
-        r = string.rfind("1")
-        while r != -1:
-            yield l - r - 1
-            r = string.rfind("1", 0, r)
-
-    def msb(bb, _bin=bin, _len=len):
-        string = _bin(bb)
-        return _len(string) - 1 - string.find("1")
-
-    def scan_reversed(bb, _bin=bin, _len=len):
-        string = _bin(bb)
-        l = _len(string)
-        r = string.find("1")
-        while r != -1:
-            yield l - r - 1
-            r = string.find("1", r + 1)
-else:
-    def lsb(bb):
-        return (bb & -bb).bit_length() - 1
-
-    def scan_forward(bb):
-        while bb:
-            r = bb & -bb
-            yield r.bit_length() - 1
-            bb ^= r
-
-    def msb(bb):
-        return bb.bit_length() - 1
-
-    def scan_reversed(bb, _BB_SQUARES=BB_SQUARES):
-        while bb:
-            r = bb.bit_length() - 1
-            yield r
-            bb ^= _BB_SQUARES[r]
+def lsb(bb):
+    return (bb & -bb).bit_length() - 1
+
+def scan_forward(bb):
+    while bb:
+        r = bb & -bb
+        yield r.bit_length() - 1
+        bb ^= r
+
+def msb(bb):
+    return bb.bit_length() - 1
 
+def scan_reversed(bb, _BB_SQUARES=BB_SQUARES):
+    while bb:
+        r = bb.bit_length() - 1
+        yield r
+        bb ^= _BB_SQUARES[r]
 
 def popcount(b, _bin=bin):
     return _bin(b).count("1")
diff --git a/chess/engine.py b/chess/engine.py
@@ -16,22 +16,19 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
+import collections
 import logging
 import threading
 import os
 import sys
 import signal
 import platform
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
 
 try:
-    import queue
+    import queue  # Python 3
 except ImportError:
-    import Queue as queue
+    import Queue as queue  # Python 2
 
 if os.name == "posix" and sys.version_info[0] < 3:
     try:
diff --git a/chess/gaviota.py b/chess/gaviota.py
@@ -17,6 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
+import collections
 import ctypes
 import ctypes.util
 import fnmatch
@@ -26,11 +27,6 @@
 import struct
 import chess
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
-
 
 LOGGER = logging.getLogger(__name__)
 
diff --git a/chess/pgn.py b/chess/pgn.py
@@ -17,15 +17,11 @@
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 import chess
+import collections
 import itertools
 import re
 import logging
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
-
 
 LOGGER = logging.getLogger(__name__)
 
diff --git a/chess/polyglot.py b/chess/polyglot.py
@@ -17,15 +17,12 @@
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 import chess
+import collections
 import struct
 import os
 import mmap
 import random
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
 
 ENTRY_STRUCT = struct.Struct(">QHHI")
 
diff --git a/chess/svg.py b/chess/svg.py
@@ -23,15 +23,11 @@
 from __future__ import division
 
 import chess
+import collections
 import math
 
 import xml.etree.ElementTree as ET
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
-
 
 SQUARE_SIZE = 45
 
diff --git a/chess/uci.py b/chess/uci.py
@@ -16,6 +16,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
+import chess
+
 from chess.engine import EngineTerminatedException
 from chess.engine import EngineStateException
 from chess.engine import MockProcess
@@ -28,16 +30,10 @@
 from chess.engine import _popen_engine
 from chess.engine import _spur_spawn_engine
 
-import chess
-
+import collections
 import concurrent.futures
 import threading
 
-try:
-    import backport_collections as collections
-except ImportError:
-    import collections
-
 
 class Score(collections.namedtuple("Score", "cp mate")):
     """A *cp* (centipawns) or *mate* score sent by an UCI engine."""
diff --git a/setup.py b/setup.py
@@ -53,15 +53,6 @@ def read_description():
     return description
 
 
-def dependencies():
-    deps = []
-
-    if sys.version_info < (2, 7):
-        deps.append("backport_collections")
-
-    return deps
-
-
 def extra_dependencies():
     extras = {}
 
@@ -78,9 +69,6 @@ def extra_dependencies():
 
     extras["test"] = extras["engine"] + extras.get("gaviota", [])
 
-    if sys.version_info < (2, 7):
-        extras["test"].append("unittest2")
-
     if platform.python_implementation() == "CPython":
         extras["test"].append("spur")
 
@@ -99,8 +87,7 @@ def extra_dependencies():
     url="https://github.com/niklasf/python-chess",
     packages=["chess"],
     test_suite="test",
-    python_requires=">=2.6,!=3.0.*,!=3.1.*,!=3.2.*",
-    install_requires=dependencies(),
+    python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*",
     extras_require=extra_dependencies(),
     tests_require=extra_dependencies().get("test"),
     classifiers=[
@@ -111,7 +98,6 @@ def extra_dependencies():
         "Operating System :: OS Independent",
         "Programming Language :: Python",
         "Programming Language :: Python :: 2",
-        "Programming Language :: Python :: 2.6",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.3",
diff --git a/test.py b/test.py
diff --git a/tox.ini b/tox.ini
