Introduce a new monkey module to encapsulate the monkeypatching.

1 files changed, 22 insertions, 0 deletions

diff --git a/setuptools/monkey.py b/setuptools/monkey.py
new file mode 100644
index 00000000..b6baf49d
--- /dev/null
+++ b/setuptools/monkey.py
@@ -0,0 +1,22 @@
+"""
+Monkey patching of distutils.
+"""
+
+
+__all__ = []
+"everything is private"
+
+
+def _get_unpatched(cls):
+    """Protect against re-patching the distutils if reloaded
+
+    Also ensures that no other distutils extension monkeypatched the distutils
+    first.
+    """
+    while cls.__module__.startswith('setuptools'):
+        cls, = cls.__bases__
+    if not cls.__module__.startswith('distutils'):
+        raise AssertionError(
+            "distutils has already been patched by %r" % cls
+        )
+    return cls