Remove Python 2 support

.coveragerc

@@ -7,4 +7,3 @@ omit =
 [report]
 exclude_lines =
     pragma: no cover
-    pragma: py$MAJOR_PYTHON_VERSION no cover

.travis.yml

@@ -1,19 +1,13 @@
 sudo: false
 language: python
 python:
-    - "2.7"
-    - "3.4"
     - "3.5"
     - "3.6"
-    - "3.7-dev"
-    - "pypy"
-
-# Enable 3.7 without globally enabling sudo and dist: xenial for other build jobs
-matrix:
-    include:
-    - python: 3.7
-      dist: xenial
-      sudo: true
+    - "3.7"
+    - "3.8"
+    - "3.9-dev"
+    - "pypy3.5-7.0"
+    - "pypy3.6-7.1.1"
 
 env:
     - PEP8_IGNORE="E731,W503,E402"

README.rst

@@ -73,7 +73,7 @@ This builds a standard wordcount function from pieces within ``toolz``:
 Dependencies
 ------------
 
-``toolz`` supports Python 2.7 and Python 3.4+ with a common codebase.
+``toolz`` supports Python 3.5+ with a common codebase.
 It is pure Python and requires no dependencies beyond the standard
 library.
 

doc/source/install.rst

@@ -11,4 +11,4 @@ three ways:
 
 1.  Toolz is pure Python
 2.  Toolz relies only on the standard library
-3.  Toolz simultaneously supports Python versions 2.7, 3.4+, PyPy
+3.  Toolz simultaneously supports Python versions 3.4+ and PyPy

doc/source/references.rst

@@ -7,9 +7,9 @@ References
    similar library for Ruby
 -  `Clojure <http://clojure.org>`__: A functional language whose
    standard library has several counterparts in ``toolz``
--  `itertools <http://docs.python.org/2/library/itertools.html>`__: The
+-  `itertools <http://docs.python.org/3/library/itertools.html>`__: The
    Python standard library for iterator tools
--  `functools <http://docs.python.org/2/library/functools.html>`__: The
+-  `functools <http://docs.python.org/3/library/functools.html>`__: The
    Python standard library for function tools
 -  `Functional Programming HOWTO <http://docs.python.org/dev/howto/functional.html>`__:
    The description of functional programming features from the official

setup.py

@@ -21,17 +21,15 @@
       long_description=(open('README.rst').read() if exists('README.rst')
                         else ''),
       zip_safe=False,
-      python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
+      python_requires=">=3.5",
       classifiers=[
           "Development Status :: 5 - Production/Stable",
           "License :: OSI Approved :: BSD License",
           "Programming Language :: Python",
-          "Programming Language :: Python :: 2",
-          "Programming Language :: Python :: 2.7",
           "Programming Language :: Python :: 3",
-          "Programming Language :: Python :: 3.4",
           "Programming Language :: Python :: 3.5",
           "Programming Language :: Python :: 3.6",
           "Programming Language :: Python :: 3.7",
+          "Programming Language :: Python :: 3.8",
           "Programming Language :: Python :: Implementation :: CPython",
           "Programming Language :: Python :: Implementation :: PyPy"])

toolz/__init__.py

@@ -6,12 +6,14 @@
 
 from .recipes import *
 
-from .compatibility import map, filter
-
 from functools import partial, reduce
 
 sorted = sorted
 
+map = map
+
+filter = filter
+
 # Aliases
 comp = compose
 

toolz/_signatures.py

@@ -18,14 +18,10 @@
 import operator
 from importlib import import_module
 
-from .compatibility import PY3
 from .functoolz import (is_partial_args, is_arity, has_varargs,
                         has_keywords, num_required_args)
 
-if PY3:  # pragma: py2 no cover
-    import builtins
-else:  # pragma: py3 no cover
-    import __builtin__ as builtins
+import builtins
 
 # We mock builtin callables using lists of tuples with lambda functions.
 #
@@ -235,54 +231,33 @@
     lambda source, globals: None,
     lambda source, globals, locals: None]
 
-if PY3:  # pragma: py2 no cover
-    module_info[builtins].update(
-        breakpoint=[
-            lambda *args, **kws: None],
-        bytes=[
-            lambda: None,
-            lambda int: None,
-            lambda string, encoding='utf8', errors='strict': None],
-        compile=[
-            (0, lambda source, filename, mode, flags=0,
-                dont_inherit=False, optimize=-1: None)],
-        max=[
-            (1, lambda iterable: None, ('default', 'key',)),
-            (1, lambda arg1, arg2, *args: None, ('key',))],
-        min=[
-            (1, lambda iterable: None, ('default', 'key',)),
-            (1, lambda arg1, arg2, *args: None, ('key',))],
-        open=[
-            (0, lambda file, mode='r', buffering=-1, encoding=None,
-                errors=None, newline=None, closefd=True, opener=None: None)],
-        sorted=[
-            (1, lambda iterable: None, ('key', 'reverse'))],
-        str=[
-            lambda object='', encoding='utf', errors='strict': None],
-    )
-    module_info[builtins]['print'] = [
-        (0, lambda *args: None, ('sep', 'end', 'file', 'flush',))]
-
-else:  # pragma: py3 no cover
-    module_info[builtins].update(
-        bytes=[
-            lambda object='': None],
-        compile=[
-            (0, lambda source, filename, mode, flags=0,
-                dont_inherit=False: None)],
-        max=[
-            (1, lambda iterable, *args: None, ('key',))],
-        min=[
-            (1, lambda iterable, *args: None, ('key',))],
-        open=[
-            (0, lambda file, mode='r', buffering=-1: None)],
-        sorted=[
-            lambda iterable, cmp=None, key=None, reverse=False: None],
-        str=[
-            lambda object='': None],
-    )
-    module_info[builtins]['print'] = [
-        (0, lambda *args: None, ('sep', 'end', 'file',))]
+module_info[builtins].update(
+    breakpoint=[
+        lambda *args, **kws: None],
+    bytes=[
+        lambda: None,
+        lambda int: None,
+        lambda string, encoding='utf8', errors='strict': None],
+    compile=[
+        (0, lambda source, filename, mode, flags=0,
+            dont_inherit=False, optimize=-1: None)],
+    max=[
+        (1, lambda iterable: None, ('default', 'key',)),
+        (1, lambda arg1, arg2, *args: None, ('key',))],
+    min=[
+        (1, lambda iterable: None, ('default', 'key',)),
+        (1, lambda arg1, arg2, *args: None, ('key',))],
+    open=[
+        (0, lambda file, mode='r', buffering=-1, encoding=None,
+            errors=None, newline=None, closefd=True, opener=None: None)],
+    sorted=[
+        (1, lambda iterable: None, ('key', 'reverse'))],
+    str=[
+        lambda object='', encoding='utf', errors='strict': None],
+)
+module_info[builtins]['print'] = [
+    (0, lambda *args: None, ('sep', 'end', 'file', 'flush',))]
+
 
 module_info[functools] = dict(
     cmp_to_key=[
@@ -346,16 +321,11 @@
         (0, lambda *iterables: None, ('fillvalue',))],
 )
 
-if PY3:  # pragma: py2 no cover
-    module_info[itertools].update(
-        product=[
-            (0, lambda *iterables: None, ('repeat',))],
-    )
-else:  # pragma: py3 no cover
-    module_info[itertools].update(
-        product=[
-            lambda *iterables: None],
-    )
+module_info[itertools].update(
+    product=[
+        (0, lambda *iterables: None, ('repeat',))],
+)
+
 
 module_info[operator] = dict(
     __abs__=[
@@ -622,51 +592,31 @@
             classval=None: None)],
 )
 
-if PY3:  # pragma: py2 no cover
-    def num_pos_args(sigspec):
-        """ Return the number of positional arguments.  ``f(x, y=1)`` has 1"""
-        return sum(1 for x in sigspec.parameters.values()
-                   if x.kind == x.POSITIONAL_OR_KEYWORD
-                   and x.default is x.empty)
-
-    def get_exclude_keywords(num_pos_only, sigspec):
-        """ Return the names of position-only arguments if func has **kwargs"""
-        if num_pos_only == 0:
-            return ()
-        has_kwargs = any(x.kind == x.VAR_KEYWORD
-                         for x in sigspec.parameters.values())
-        if not has_kwargs:
-            return ()
-        pos_args = list(sigspec.parameters.values())[:num_pos_only]
-        return tuple(x.name for x in pos_args)
-
-    def signature_or_spec(func):
-        try:
-            return inspect.signature(func)
-        except (ValueError, TypeError):
-            return None
-
-else:  # pragma: py3 no cover
-    def num_pos_args(sigspec):
-        """ Return the number of positional arguments.  ``f(x, y=1)`` has 1"""
-        if sigspec.defaults:
-            return len(sigspec.args) - len(sigspec.defaults)
-        return len(sigspec.args)
-
-    def get_exclude_keywords(num_pos_only, sigspec):
-        """ Return the names of position-only arguments if func has **kwargs"""
-        if num_pos_only == 0:
-            return ()
-        has_kwargs = sigspec.keywords is not None
-        if not has_kwargs:
-            return ()
-        return tuple(sigspec.args[:num_pos_only])
-
-    def signature_or_spec(func):
-        try:
-            return inspect.getargspec(func)
-        except TypeError:
-            return None
+
+def num_pos_args(sigspec):
+    """ Return the number of positional arguments.  ``f(x, y=1)`` has 1"""
+    return sum(1 for x in sigspec.parameters.values()
+               if x.kind == x.POSITIONAL_OR_KEYWORD
+               and x.default is x.empty)
+
+
+def get_exclude_keywords(num_pos_only, sigspec):
+    """ Return the names of position-only arguments if func has **kwargs"""
+    if num_pos_only == 0:
+        return ()
+    has_kwargs = any(x.kind == x.VAR_KEYWORD
+                     for x in sigspec.parameters.values())
+    if not has_kwargs:
+        return ()
+    pos_args = list(sigspec.parameters.values())[:num_pos_only]
+    return tuple(x.name for x in pos_args)
+
+
+def signature_or_spec(func):
+    try:
+        return inspect.signature(func)
+    except (ValueError, TypeError):
+        return None
 
 
 def expand_sig(sig):
@@ -792,7 +742,7 @@ def _has_varargs(func):
     checks = [check_varargs(sig) for sig in sigs]
     if all(checks):
         return True
-    elif any(checks):  # pragma: py2 no cover
+    elif any(checks):
         return None
     return False
 

toolz/compatibility.py

@@ -1,34 +1,30 @@
+import warnings
+warnings.warn("The toolz.compatibility module is no longer "
+              "needed in Python 3 and has been deprecated. Please "
+              "import these utilities directly from the standard library. "
+              "This module will be removed in a future release.",
+              category=DeprecationWarning)
+
 import operator
 import sys
+
 PY3 = sys.version_info[0] > 2
 PY34 = sys.version_info[0] == 3 and sys.version_info[1] == 4
-PYPY = hasattr(sys, 'pypy_version_info')
+PYPY = hasattr(sys, 'pypy_version_info') and PY3
 
 __all__ = ('map', 'filter', 'range', 'zip', 'reduce', 'zip_longest',
            'iteritems', 'iterkeys', 'itervalues', 'filterfalse',
            'PY3', 'PY34', 'PYPY')
 
-if PY3:
-    map = map
-    filter = filter
-    range = range
-    zip = zip
-    from functools import reduce
-    from itertools import zip_longest
-    from itertools import filterfalse
-    iteritems = operator.methodcaller('items')
-    iterkeys = operator.methodcaller('keys')
-    itervalues = operator.methodcaller('values')
-    from collections.abc import Sequence, Mapping
-else:
-    range = xrange
-    reduce = reduce
-    from itertools import imap as map
-    from itertools import ifilter as filter
-    from itertools import ifilterfalse as filterfalse
-    from itertools import izip as zip
-    from itertools import izip_longest as zip_longest
-    iteritems = operator.methodcaller('iteritems')
-    iterkeys = operator.methodcaller('iterkeys')
-    itervalues = operator.methodcaller('itervalues')
-    from collections import Sequence, Mapping
+
+map = map
+filter = filter
+range = range
+zip = zip
+from functools import reduce
+from itertools import zip_longest
+from itertools import filterfalse
+iteritems = operator.methodcaller('items')
+iterkeys = operator.methodcaller('keys')
+itervalues = operator.methodcaller('values')
+from collections.abc import Sequence