Use unique_everseen from more_itertools.

1 files changed, 2 insertions, 20 deletions

diff --git a/setuptools/command/build_py.py b/setuptools/command/build_py.py
index b30aa129..df6fd323 100644
--- a/setuptools/command/build_py.py
+++ b/setuptools/command/build_py.py
@@ -8,6 +8,7 @@ import io
 import distutils.errors
 import itertools
 import stat
+from setuptools.extern.more_itertools import unique_everseen
 
 try:
     from setuptools.lib2to3_ex import Mixin2to3
@@ -214,7 +215,7 @@ class build_py(orig.build_py, Mixin2to3):
             if fn not in bad
         )
         # ditch dupes
-        return list(_unique_everseen(keepers))
+        return list(unique_everseen(keepers))
 
     @staticmethod
     def _get_platform_patterns(spec, package, src_dir):
@@ -235,25 +236,6 @@ class build_py(orig.build_py, Mixin2to3):
         )
 
 
-# from Python docs
-def _unique_everseen(iterable, key=None):
-    "List unique elements, preserving order. Remember all elements ever seen."
-    # unique_everseen('AAAABBBCCDAABBB') --> A B C D
-    # unique_everseen('ABBCcAD', str.lower) --> A B C D
-    seen = set()
-    seen_add = seen.add
-    if key is None:
-        for element in itertools.filterfalse(seen.__contains__, iterable):
-            seen_add(element)
-            yield element
-    else:
-        for element in iterable:
-            k = key(element)
-            if k not in seen:
-                seen_add(k)
-                yield element
-
-
 def assert_relative(path):
     if not os.path.isabs(path):
         return path