pypa · jaraco · Sep 5, 2021 · Sep 5, 2021 · Sep 5, 2021 · Oct 20, 2021
diff --git a/MANIFEST.in b/MANIFEST.in
@@ -2,7 +2,6 @@ recursive-include setuptools *.py *.exe *.xml *.tmpl
 recursive-include tests *.py
 recursive-include setuptools/tests *.html
 recursive-include docs *.py *.txt *.rst *.conf *.css *.css_t Makefile indexsidebar.html
-recursive-include setuptools/_vendor *.py *.txt
 recursive-include pkg_resources *.py *.txt
 recursive-include pkg_resources/tests/data *
 recursive-include tools *

diff --git a/changelog.d/2764.breaking.rst b/changelog.d/2764.breaking.rst
@@ -0,0 +1 @@
+Setuptools now declares its dependencies in metadata but also vendors libraries satisfying those dependencies if they're not present. This change means that Setuptools cannot install from source under pip earlier than 20.
diff --git a/conftest.py b/conftest.py
@@ -16,11 +16,7 @@ def pytest_addoption(parser):
     'setuptools/tests/mod_with_constant.py',
     'setuptools/_distutils',
     '_distutils_hack',
-    'setuptools/extern',
-    'pkg_resources/extern',
     'pkg_resources/tests/data',
-    'setuptools/_vendor',
-    'pkg_resources/_vendor',
 ]
 
 

diff --git a/pavement.py b/pavement.py
diff --git a/pkg_resources/__init__.py b/pkg_resources/__init__.py
@@ -71,12 +71,11 @@
 except ImportError:
     importlib_machinery = None
 
-from pkg_resources.extern import appdirs
-from pkg_resources.extern import packaging
-__import__('pkg_resources.extern.packaging.version')
-__import__('pkg_resources.extern.packaging.specifiers')
-__import__('pkg_resources.extern.packaging.requirements')
-__import__('pkg_resources.extern.packaging.markers')
+import appdirs
+import packaging.version
+import packaging.specifiers
+import packaging.requirements
+import packaging.markers
 
 if sys.version_info < (3, 5):
     raise RuntimeError("Python 3.5 or later is required")

diff --git a/pkg_resources/_vendor/__init__.py b/pkg_resources/_vendor/__init__.py