Merge branch 'clean' of https://github.com/pypa/distutils into master

3 files changed, 43 insertions, 4 deletions

diff --git a/setuptools/_distutils/_msvccompiler.py b/setuptools/_distutils/_msvccompiler.py
index 0e98692e..2d56ee0a 100644
--- a/setuptools/_distutils/_msvccompiler.py
+++ b/setuptools/_distutils/_msvccompiler.py
@@ -15,7 +15,9 @@ for older versions in distutils.msvc9compiler and distutils.msvccompiler.
 
 import os
 import subprocess
-import winreg
+import contextlib
+with contextlib.suppress(ImportError):
+    import winreg
 
 from distutils.errors import DistutilsExecError, DistutilsPlatformError, \
                              CompileError, LibError, LinkError
@@ -501,7 +503,7 @@ class MSVCCompiler(CCompiler) :
             log.debug("skipping %s (up-to-date)", output_filename)
 
     def spawn(self, cmd):
-        env = dict(os.environ, path=self._paths)
+        env = dict(os.environ, PATH=self._paths)
         return super().spawn(cmd, env=env)
 
     # -- Miscellaneous methods -----------------------------------------
diff --git a/setuptools/_distutils/ccompiler.py b/setuptools/_distutils/ccompiler.py
index b5ef143e..57bb94e8 100644
--- a/setuptools/_distutils/ccompiler.py
+++ b/setuptools/_distutils/ccompiler.py
@@ -906,8 +906,8 @@ int main (int argc, char **argv) {
     def execute(self, func, args, msg=None, level=1):
         execute(func, args, msg, self.dry_run)
 
-    def spawn(self, cmd):
-        spawn(cmd, dry_run=self.dry_run)
+    def spawn(self, cmd, **kwargs):
+        spawn(cmd, dry_run=self.dry_run, **kwargs)
 
     def move_file(self, src, dst):
         return move_file(src, dst, dry_run=self.dry_run)
diff --git a/setuptools/_distutils/tests/test_msvccompiler.py b/setuptools/_distutils/tests/test_msvccompiler.py
index b518d6a7..88d912b1 100644
--- a/setuptools/_distutils/tests/test_msvccompiler.py
+++ b/setuptools/_distutils/tests/test_msvccompiler.py
@@ -2,6 +2,7 @@
 import sys
 import unittest
 import os
+import threading
 
 from distutils.errors import DistutilsPlatformError
 from distutils.tests import support
@@ -74,6 +75,42 @@ class msvccompilerTestCase(support.TempdirManager,
         else:
             raise unittest.SkipTest("VS 2015 is not installed")
 
+
+class CheckThread(threading.Thread):
+    exc_info = None
+
+    def run(self):
+        try:
+            super().run()
+        except Exception:
+            self.exc_info = sys.exc_info()
+
+    def __bool__(self):
+        return not self.exc_info
+
+
+class TestSpawn(unittest.TestCase):
+    def test_concurrent_safe(self):
+        """
+        Concurrent calls to spawn should have consistent results.
+        """
+        import distutils._msvccompiler as _msvccompiler
+        compiler = _msvccompiler.MSVCCompiler()
+        compiler._paths = "expected"
+        inner_cmd = 'import os; assert os.environ["PATH"] == "expected"'
+        command = ['python', '-c', inner_cmd]
+
+        threads = [
+            CheckThread(target=compiler.spawn, args=[command])
+            for n in range(100)
+        ]
+        for thread in threads:
+            thread.start()
+        for thread in threads:
+            thread.join()
+        assert all(threads)
+
+
 def test_suite():
     return unittest.makeSuite(msvccompilerTestCase)