From a69701c495947a2bbe618e71e20d6203977a6943 Mon Sep 17 00:00:00 2001
From: Brian Rosmaita <rosmaita.fossdev@gmail.com>
Date: Wed, 11 Apr 2018 22:46:33 -0400
Subject: [PATCH] Make List option format bounds-sensitive

The List ConfigType has a boolean 'bounds' option that indicates
whether the value must be enclosed in brackets.  This patch modifies
the List formatter so that when bounds=True the output is displayed
in enclosing brackets.

Change-Id: Ide3748e67d14191b6b33c97c7d8437e4888e61d5
Closes-bug: #1763239
---
 oslo_config/tests/test_generator.py | 15 +++++++++++++++
 oslo_config/types.py                |  5 +++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/oslo_config/tests/test_generator.py b/oslo_config/tests/test_generator.py
index e01bbab3..8575d8e2 100644
--- a/oslo_config/tests/test_generator.py
+++ b/oslo_config/tests/test_generator.py
@@ -151,6 +151,10 @@ class GeneratorTestCase(base.BaseTestCase):
         'list_opt': cfg.ListOpt('list_opt',
                                 default=['1', '2', '3'],
                                 help='a list'),
+        'list_opt_with_bounds': cfg.ListOpt('list_opt_with_bounds',
+                                            default=['1', '2', '3'],
+                                            help='a list',
+                                            bounds=True),
         'list_opt_single': cfg.ListOpt('list_opt_single',
                                        default='1',
                                        help='a list'),
@@ -630,6 +634,17 @@ class GeneratorTestCase(base.BaseTestCase):
 
 # a list (list value)
 #list_opt = 1,2,3
+''')),
+        ('list_opt_with_bounds',
+         dict(opts=[('test', [(None, [opts['list_opt_with_bounds']])])],
+              expected='''[DEFAULT]
+
+#
+# From test
+#
+
+# a list (list value)
+#list_opt_with_bounds = [1,2,3]
 ''')),
         ('list_opt_single',
          dict(opts=[('test', [(None, [opts['list_opt_single']])])],
diff --git a/oslo_config/types.py b/oslo_config/types.py
index 752fe1a8..06a81dde 100644
--- a/oslo_config/types.py
+++ b/oslo_config/types.py
@@ -525,14 +525,15 @@ class List(ConfigType):
         )
 
     def _formatter(self, value):
+        fmtstr = '[{}]' if self.bounds else '{}'
         if isinstance(value, six.string_types):
-            return value
+            return fmtstr.format(value)
         if isinstance(value, list):
             value = [
                 six.text_type(v)
                 for v in value
             ]
-        return ','.join(value)
+        return fmtstr.format(','.join(value))
 
 
 class Range(ConfigType):