1 files changed, 39 insertions, 0 deletions
diff --git a/setuptools/tests/test_sandbox.py b/setuptools/tests/test_sandbox.py
index 6e1e9e1c..fefd46f7 100644
--- a/setuptools/tests/test_sandbox.py
+++ b/setuptools/tests/test_sandbox.py
@@ -100,3 +100,42 @@ class TestExceptionSaver:
             saved_exc.resume()
 
         assert str(caught.value) == "CantPickleThis('detail',)"
+
+    def test_unpickleable_exception_when_hiding_setuptools(self):
+        """
+        As revealed in #440, an infinite recursion can occur if an unpickleable
+        exception while setuptools is hidden. Ensure this doesn't happen.
+        """
+        class ExceptionUnderTest(Exception):
+            """
+            An unpickleable exception (not in globals).
+            """
+
+        with pytest.raises(setuptools.sandbox.UnpickleableException) as caught:
+            with setuptools.sandbox.save_modules():
+                setuptools.sandbox.hide_setuptools()
+                raise ExceptionUnderTest()
+
+        msg, = caught.value.args
+        assert msg == 'ExceptionUnderTest()'
+
+    def test_sandbox_violation_raised_hiding_setuptools(self, tmpdir):
+        """
+        When in a sandbox with setuptools hidden, a SandboxViolation
+        should reflect a proper exception and not be wrapped in
+        an UnpickleableException.
+        """
+        def write_file():
+            "Trigger a SandboxViolation by writing outside the sandbox"
+            with open('/etc/foo', 'w'):
+                pass
+        sandbox = DirectorySandbox(str(tmpdir))
+        with pytest.raises(setuptools.sandbox.SandboxViolation) as caught:
+            with setuptools.sandbox.save_modules():
+                setuptools.sandbox.hide_setuptools()
+                sandbox.run(write_file)
+
+        cmd, args, kwargs = caught.value.args
+        assert cmd == 'open'
+        assert args == ('/etc/foo', 'w')
+        assert kwargs == {}