From 3913e338f0ec1cdd570e419a8add114ac8aafe20 Mon Sep 17 00:00:00 2001
From: DongHun Kwak <dh0128.kwak@samsung.com>
Date: Wed, 30 Dec 2020 07:08:59 +0900
Subject: [PATCH] Imported Upstream version 50.3.0

---
 .bumpversion.cfg                              |  2 +-
 CHANGES.rst                                   |  6 +++++
 setup.cfg                                     |  2 +-
 setuptools/_distutils/_msvccompiler.py        | 26 ++++++++++++++++++-
 .../_distutils/tests/test_msvccompiler.py     | 20 ++++++++++++++
 5 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 0bb91b4..7a0aef4 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 50.2.0
+current_version = 50.3.0
 commit = True
 tag = True
 
diff --git a/CHANGES.rst b/CHANGES.rst
index 9962f63..83b56b6 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,9 @@
+v50.3.0
+-------
+
+* #2368: In distutils, restore support for monkeypatched CCompiler.spawn per pypa/distutils#15.
+
+
 v50.2.0
 -------
 
diff --git a/setup.cfg b/setup.cfg
index d35e5fa..7851845 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -16,7 +16,7 @@ formats = zip
 
 [metadata]
 name = setuptools
-version = 50.2.0
+version = 50.3.0
 description = Easily download, build, install, upgrade, and uninstall Python packages
 author = Python Packaging Authority
 author_email = distutils-sig@python.org
diff --git a/setuptools/_distutils/_msvccompiler.py b/setuptools/_distutils/_msvccompiler.py
index 2d56ee0..e9af4cf 100644
--- a/setuptools/_distutils/_msvccompiler.py
+++ b/setuptools/_distutils/_msvccompiler.py
@@ -16,6 +16,8 @@ for older versions in distutils.msvc9compiler and distutils.msvccompiler.
 import os
 import subprocess
 import contextlib
+import warnings
+import unittest.mock
 with contextlib.suppress(ImportError):
     import winreg
 
@@ -504,7 +506,29 @@ class MSVCCompiler(CCompiler) :
 
     def spawn(self, cmd):
         env = dict(os.environ, PATH=self._paths)
-        return super().spawn(cmd, env=env)
+        with self._fallback_spawn(cmd, env) as fallback:
+            return super().spawn(cmd, env=env)
+        return fallback.value
+
+    @contextlib.contextmanager
+    def _fallback_spawn(self, cmd, env):
+        """
+        Discovered in pypa/distutils#15, some tools monkeypatch the compiler,
+        so the 'env' kwarg causes a TypeError. Detect this condition and
+        restore the legacy, unsafe behavior.
+        """
+        bag = type('Bag', (), {})()
+        try:
+            yield bag
+        except TypeError as exc:
+            if "unexpected keyword argument 'env'" not in str(exc):
+                raise
+        else:
+            return
+        warnings.warn(
+            "Fallback spawn triggered. Please update distutils monkeypatch.")
+        with unittest.mock.patch('os.environ', env):
+            bag.value = super().spawn(cmd)
 
     # -- Miscellaneous methods -----------------------------------------
     # These are all used by the 'gen_lib_options() function, in
diff --git a/setuptools/_distutils/tests/test_msvccompiler.py b/setuptools/_distutils/tests/test_msvccompiler.py
index 88d912b..46a51cd 100644
--- a/setuptools/_distutils/tests/test_msvccompiler.py
+++ b/setuptools/_distutils/tests/test_msvccompiler.py
@@ -110,6 +110,26 @@ class TestSpawn(unittest.TestCase):
             thread.join()
         assert all(threads)
 
+    def test_concurrent_safe_fallback(self):
+        """
+        If CCompiler.spawn has been monkey-patched without support
+        for an env, it should still execute.
+        """
+        import distutils._msvccompiler as _msvccompiler
+        from distutils import ccompiler
+        compiler = _msvccompiler.MSVCCompiler()
+        compiler._paths = "expected"
+
+        def CCompiler_spawn(self, cmd):
+            "A spawn without an env argument."
+            assert os.environ["PATH"] == "expected"
+
+        with unittest.mock.patch.object(
+                ccompiler.CCompiler, 'spawn', CCompiler_spawn):
+            compiler.spawn(["n/a"])
+
+        assert os.environ.get("PATH") != "expected"
+
 
 def test_suite():
     return unittest.makeSuite(msvccompilerTestCase)
-- 
2.34.1