merge heads

2 files changed, 57 insertions, 13 deletions

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 775db50..57cc1a4 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1327,6 +1327,7 @@ class Popen(object):
 
             if executable is None:
                 executable = args[0]
+            orig_executable = executable
 
             # For transferring possible exec failure from child to parent.
             # Data format: "exception name:hex errno:description"
@@ -1409,10 +1410,17 @@ class Popen(object):
                 err_msg = err_msg.decode(errors="surrogatepass")
                 if issubclass(child_exception_type, OSError) and hex_errno:
                     errno_num = int(hex_errno, 16)
+                    child_exec_never_called = (err_msg == "noexec")
+                    if child_exec_never_called:
+                        err_msg = ""
                     if errno_num != 0:
                         err_msg = os.strerror(errno_num)
                         if errno_num == errno.ENOENT:
-                            err_msg += ': ' + repr(args[0])
+                            if child_exec_never_called:
+                                # The error must be from chdir(cwd).
+                                err_msg += ': ' + repr(cwd)
+                            else:
+                                err_msg += ': ' + repr(orig_executable)
                     raise child_exception_type(errno_num, err_msg)
                 raise child_exception_type(err_msg)
 
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 07e2b4b..b260c81 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -200,13 +200,16 @@ class ProcessTestCase(BaseTestCase):
         p.wait()
         self.assertEqual(47, p.returncode)
 
-    # TODO: make this test work on Linux.
-    # This may be failing on Linux because of issue #7774.
-    @unittest.skipIf(sys.platform not in ('win32', 'darwin'),
-                     "possible bug using executable argument on Linux")
     def test_executable(self):
         # Check that the executable argument works.
-        self._assert_python(["doesnotexist", "-c"], executable=sys.executable)
+        #
+        # On Unix (non-Mac and non-Windows), Python looks at args[0] to
+        # determine where its standard library is, so we need the directory
+        # of args[0] to be valid for the Popen() call to Python to succeed.
+        # See also issue #16170 and issue #7774.
+        doesnotexist = os.path.join(os.path.dirname(sys.executable),
+                                    "doesnotexist")
+        self._assert_python([doesnotexist, "-c"], executable=sys.executable)
 
     def test_executable_takes_precedence(self):
         # Check that the executable argument takes precedence over args[0].
@@ -1035,24 +1038,30 @@ class _SuppressCoreFiles(object):
 @unittest.skipIf(mswindows, "POSIX specific tests")
 class POSIXProcessTestCase(BaseTestCase):
 
-    def test_exceptions(self):
-        nonexistent_dir = "/_this/pa.th/does/not/exist"
+    def setUp(self):
+        super().setUp()
+        self._nonexistent_dir = "/_this/pa.th/does/not/exist"
+
+    def _get_chdir_exception(self):
         try:
-            os.chdir(nonexistent_dir)
+            os.chdir(self._nonexistent_dir)
         except OSError as e:
             # This avoids hard coding the errno value or the OS perror()
             # string and instead capture the exception that we want to see
             # below for comparison.
             desired_exception = e
-            desired_exception.strerror += ': ' + repr(sys.executable)
+            desired_exception.strerror += ': ' + repr(self._nonexistent_dir)
         else:
             self.fail("chdir to nonexistant directory %s succeeded." %
-                      nonexistent_dir)
+                      self._nonexistent_dir)
+        return desired_exception
 
-        # Error in the child re-raised in the parent.
+    def test_exception_cwd(self):
+        """Test error in the child raised in the parent for a bad cwd."""
+        desired_exception = self._get_chdir_exception()
         try:
             p = subprocess.Popen([sys.executable, "-c", ""],
-                                 cwd=nonexistent_dir)
+                                 cwd=self._nonexistent_dir)
         except OSError as e:
             # Test that the child process chdir failure actually makes
             # it up to the parent process as the correct exception.
@@ -1061,6 +1070,33 @@ class POSIXProcessTestCase(BaseTestCase):
         else:
             self.fail("Expected OSError: %s" % desired_exception)
 
+    def test_exception_bad_executable(self):
+        """Test error in the child raised in the parent for a bad executable."""
+        desired_exception = self._get_chdir_exception()
+        try:
+            p = subprocess.Popen([sys.executable, "-c", ""],
+                                 executable=self._nonexistent_dir)
+        except OSError as e:
+            # Test that the child process exec failure actually makes
+            # it up to the parent process as the correct exception.
+            self.assertEqual(desired_exception.errno, e.errno)
+            self.assertEqual(desired_exception.strerror, e.strerror)
+        else:
+            self.fail("Expected OSError: %s" % desired_exception)
+
+    def test_exception_bad_args_0(self):
+        """Test error in the child raised in the parent for a bad args[0]."""
+        desired_exception = self._get_chdir_exception()
+        try:
+            p = subprocess.Popen([self._nonexistent_dir, "-c", ""])
+        except OSError as e:
+            # Test that the child process exec failure actually makes
+            # it up to the parent process as the correct exception.
+            self.assertEqual(desired_exception.errno, e.errno)
+            self.assertEqual(desired_exception.strerror, e.strerror)
+        else:
+            self.fail("Expected OSError: %s" % desired_exception)
+
     def test_restore_signals(self):
         # Code coverage for both values of restore_signals to make sure it
         # at least does not blow up.