Avoid message concatenation in error path

Recently, the error message in _process_communicate_handle_oserror()
has been i18n'ed, which caused the regression as another code path
appended a string to it, which causes the TypeError to be raised.

Fix it by using string formatting instead of '+' to force it
to convert to string before concatenating.

Closes-Bug: 1421652

Change-Id: I7229b46888f798ac4a69c140ab389afed49b8c3c

2 files changed, 64 insertions, 11 deletions

diff --git a/keystoneclient/common/cms.py b/keystoneclient/common/cms.py
index 1bd0f41..21cd394 100644
--- a/keystoneclient/common/cms.py
+++ b/keystoneclient/common/cms.py
@@ -85,9 +85,7 @@ def _check_files_accessible(files):
     except IOError as e:
         # Catching IOError means there is an issue with
         # the given file.
-        err = _('Hit OSError in _process_communicate_handle_oserror()\n'
-                'Likely due to %(file)s: %(error)s') % {'file': try_file,
-                                                        'error': e.strerror}
+        err = try_file, e.strerror
         # Emulate openssl behavior, which returns with code 2 when
         # access to a file failed.
         retcode = OpensslCmsExitStatus.INPUT_FILE_READ_ERROR
@@ -111,12 +109,25 @@ def _process_communicate_handle_oserror(process, data, files):
         retcode, err = _check_files_accessible(files)
         if process.stderr:
             msg = process.stderr.read()
-            err = err + msg.decode('utf-8')
+            if isinstance(msg, six.binary_type):
+                msg = msg.decode('utf-8')
+            if err:
+                err = (_('Hit OSError in '
+                         '_process_communicate_handle_oserror(): '
+                         '%(stderr)s\nLikely due to %(file)s: %(error)s') %
+                       {'stderr': msg,
+                        'file': err[0],
+                        'error': err[1]})
+            else:
+                err = (_('Hit OSError in '
+                         '_process_communicate_handle_oserror(): %s') % msg)
+
         output = ''
     else:
         retcode = process.poll()
         if err is not None:
-            err = err.decode('utf-8')
+            if isinstance(err, six.binary_type):
+                err = err.decode('utf-8')
 
     return output, err, retcode
 
diff --git a/keystoneclient/tests/unit/test_cms.py b/keystoneclient/tests/unit/test_cms.py
index 019730d..dc1d0d1 100644
--- a/keystoneclient/tests/unit/test_cms.py
+++ b/keystoneclient/tests/unit/test_cms.py
@@ -42,6 +42,11 @@ class CMSTest(utils.TestCase, testresources.ResourcedTestCase):
             raise Exception('Your version of OpenSSL is not supported. '
                             'You will need to update it to 1.0 or later.')
 
+    def _raise_OSError(*args):
+        e = OSError()
+        e.errno = errno.EPIPE
+        raise e
+
     def test_cms_verify(self):
         self.assertRaises(exceptions.CertificateConfigError,
                           cms.cms_verify,
@@ -90,12 +95,8 @@ class CMSTest(utils.TestCase, testresources.ResourcedTestCase):
                           '/no/such/file', '/no/such/key')
 
     def test_cms_verify_token_no_oserror(self):
-        def raise_OSError(*args):
-            e = OSError()
-            e.errno = errno.EPIPE
-            raise e
-
-        with mock.patch('subprocess.Popen.communicate', new=raise_OSError):
+        with mock.patch('subprocess.Popen.communicate',
+                        new=self._raise_OSError):
             try:
                 cms.cms_verify("x", '/no/such/file', '/no/such/key')
             except exceptions.CertificateConfigError as e:
@@ -155,6 +156,47 @@ class CMSTest(utils.TestCase, testresources.ResourcedTestCase):
         # sha256 hash is 64 chars.
         self.assertThat(token_id, matchers.HasLength(64))
 
+    @mock.patch('keystoneclient.common.cms._check_files_accessible')
+    def test_process_communicate_handle_oserror_epipe(self, files_acc_mock):
+        process_mock = mock.Mock()
+        process_mock.communicate = self._raise_OSError
+        process_mock.stderr = mock.Mock()
+        process_mock.stderr.read = mock.Mock(return_value='proc stderr')
+        files_acc_mock.return_value = 1, ('file_path', 'fileerror')
+        output, err, retcode = cms._process_communicate_handle_oserror(
+            process_mock, '', [])
+
+        self.assertEqual((output, retcode), ('', 1))
+        self.assertIn('file_path', err)
+        self.assertIn('fileerror', err)
+        self.assertIn('proc stderr', err)
+
+    @mock.patch('keystoneclient.common.cms._check_files_accessible')
+    def test_process_communicate_handle_oserror_epipe_files_ok(
+            self, files_acc_mock):
+        process_mock = mock.Mock()
+        process_mock.communicate = self._raise_OSError
+        process_mock.stderr = mock.Mock()
+        process_mock.stderr.read = mock.Mock(return_value='proc stderr')
+        files_acc_mock.return_value = -1, None
+        output, err, retcode = cms._process_communicate_handle_oserror(
+            process_mock, '', [])
+
+        self.assertEqual((output, retcode), ('', -1))
+        self.assertIn('proc stderr', err)
+
+    def test_process_communicate_handle_oserror_no_exception(self):
+        process_mock = mock.Mock()
+        process_mock.communicate.return_value = 'out', 'err'
+        process_mock.poll.return_value = 0
+
+        output, err, retcode = cms._process_communicate_handle_oserror(
+            process_mock, '', [])
+
+        self.assertEqual(output, 'out')
+        self.assertEqual(err, 'err')
+        self.assertEqual(retcode, 0)
+
 
 def load_tests(loader, tests, pattern):
     return testresources.OptimisingTestSuite(tests)