Issue #10806, issue #9905: Fix subprocess pipes when some of the standard

file descriptors (0, 1, 2) are closed in the parent process.  Initial
patch by Ross Lagerwall.

Lib/test/test_subprocess.py

@@ -903,6 +903,58 @@ class POSIXProcessTestCase(BaseTestCase):
         self.assertStderrEqual(stderr, b'')
         self.assertEqual(p.wait(), -signal.SIGTERM)
 
+    def check_close_std_fds(self, fds):
+        # Issue #9905: test that subprocess pipes still work properly with
+        # some standard fds closed
+        stdin = 0
+        newfds = []
+        for a in fds:
+            b = os.dup(a)
+            newfds.append(b)
+            if a == 0:
+                stdin = b
+        try:
+            for fd in fds:
+                os.close(fd)
+            out, err = subprocess.Popen([sys.executable, "-c",
+                              'import sys;'
+                              'sys.stdout.write("apple");'
+                              'sys.stdout.flush();'
+                              'sys.stderr.write("orange")'],
+                       stdin=stdin,
+                       stdout=subprocess.PIPE,
+                       stderr=subprocess.PIPE).communicate()
+            err = support.strip_python_stderr(err)
+            self.assertEqual((out, err), (b'apple', b'orange'))
+        finally:
+            for b, a in zip(newfds, fds):
+                os.dup2(b, a)
+            for b in newfds:
+                os.close(b)
+
+    def test_close_fd_0(self):
+        self.check_close_std_fds([0])
+
+    def test_close_fd_1(self):
+        self.check_close_std_fds([1])
+
+    def test_close_fd_2(self):
+        self.check_close_std_fds([2])
+
+    def test_close_fds_0_1(self):
+        self.check_close_std_fds([0, 1])
+
+    def test_close_fds_0_2(self):
+        self.check_close_std_fds([0, 2])
+
+    def test_close_fds_1_2(self):
+        self.check_close_std_fds([1, 2])
+
+    def test_close_fds_0_1_2(self):
+        # Issue #10806: test that subprocess pipes still work properly with
+        # all standard fds closed.
+        self.check_close_std_fds([0, 1, 2])
+
     def test_surrogates_error_message(self):
         def prepare():
             raise ValueError("surrogate:\uDCff")