MAINT: be more tolerant of setuptools>=60

NumPy may fail to build with the default vendored distutils in
setuptools>=60. Rather than panic and die when new setuptools is found,
let's check (or set, if possible) the SETUPTOOLS_USE_DISTUTILS
environment variable that restores "proper" setuptools behavior.

1 files changed, 10 insertions, 3 deletions

diff --git a/setup.py b/setup.py
index c520ed69e..085b158ed 100755
--- a/setup.py
+++ b/setup.py
@@ -86,9 +86,16 @@ if os.path.exists('MANIFEST'):
 import numpy.distutils.command.sdist
 import setuptools
 if int(setuptools.__version__.split('.')[0]) >= 60:
-    raise RuntimeError(
-        "Setuptools version is '{}', version < '60.0.0' is required. "
-        "See pyproject.toml".format(setuptools.__version__))
+    # setuptools >= 60 switches to vendored distutils by default; this
+    # may break the numpy build, so make sure the stdlib version is used
+    try:
+        setuptools_use_distutils = os.environ['SETUPTOOLS_USE_DISTUTILS']
+    except KeyError:
+        os.environ['SETUPTOOLS_USE_DISTUTILS'] = "stdlib"
+    else:
+        if setuptools_use_distutils != "stdlib":
+            raise RuntimeError("setuptools versions >= '60.0.0' require "
+                    "SETUPTOOLS_USE_DISTUTILS=stdlib in the environment")
 
 # Initialize cmdclass from versioneer
 from numpy.distutils.core import numpy_cmdclass