Backport code for i18n to check lazy at runtime

Currently in the oslo-incubator version of i18n support
the TranslationFactory generates a direct translation
method based on the passed lazy parameter.   This means that
when the default is assigned to _ during its intial import,
lazy isn't specified, which defaults to False, so the
TranslationFactory returns a method that does not support
lazy translation.

The _ method is not changed until enable_lazy is called, thus
any import of _ prior to that will cache the initial method
that does not support lazy translation even when it has been
enabled.

This problem was exposed by the cinder test case:
  cinder/tests/test_wsgi.py
test
  test_cinder_exception_with_localized_explanation

when the file:
  cinder/api/middleware/fault.py
had the line:
  from cinder.openstack.common.gettextutils import _
added to it.

This behavior is corrected in the i18n library such that the
generated method checks the global _lazy.USE_LAZY to determine
if lazy translation should be used in commit:

   Iae22668 Check the lazy flag at runtime

Note that this removes the lazy parameter from the signature of
install and the TranslationFactory to match the library.

Change-Id: If1832b012d4b72708d0850367a1ec55cb0cd63e8

2 files changed, 45 insertions, 65 deletions

diff --git a/openstack/common/gettextutils.py b/openstack/common/gettextutils.py
index 87229a93..59545c49 100644
--- a/openstack/common/gettextutils.py
+++ b/openstack/common/gettextutils.py
@@ -23,7 +23,6 @@ Usual usage in an openstack.common module:
 """
 
 import copy
-import functools
 import gettext
 import locale
 from logging import handlers
@@ -42,7 +41,7 @@ class TranslatorFactory(object):
     """Create translator functions
     """
 
-    def __init__(self, domain, lazy=False, localedir=None):
+    def __init__(self, domain, localedir=None):
         """Establish a set of translation functions for the domain.
 
         :param domain: Name of translation domain,
@@ -55,7 +54,6 @@ class TranslatorFactory(object):
         :type localedir: str
         """
         self.domain = domain
-        self.lazy = lazy
         if localedir is None:
             localedir = os.environ.get(domain.upper() + '_LOCALEDIR')
         self.localedir = localedir
@@ -75,16 +73,19 @@ class TranslatorFactory(object):
         """
         if domain is None:
             domain = self.domain
-        if self.lazy:
-            return functools.partial(Message, domain=domain)
-        t = gettext.translation(
-            domain,
-            localedir=self.localedir,
-            fallback=True,
-        )
-        if six.PY3:
-            return t.gettext
-        return t.ugettext
+        t = gettext.translation(domain,
+                                localedir=self.localedir,
+                                fallback=True)
+        # Use the appropriate method of the translation object based
+        # on the python version.
+        m = t.gettext if six.PY3 else t.ugettext
+
+        def f(msg):
+            """oslo.i18n.gettextutils translation function."""
+            if USE_LAZY:
+                return Message(msg, domain=domain)
+            return m(msg)
+        return f
 
     @property
     def primary(self):
@@ -147,19 +148,11 @@ def enable_lazy():
     your project is importing _ directly instead of using the
     gettextutils.install() way of importing the _ function.
     """
-    # FIXME(dhellmann): This function will be removed in oslo.i18n,
-    # because the TranslatorFactory makes it superfluous.
-    global _, _LI, _LW, _LE, _LC, USE_LAZY
-    tf = TranslatorFactory('oslo', lazy=True)
-    _ = tf.primary
-    _LI = tf.log_info
-    _LW = tf.log_warning
-    _LE = tf.log_error
-    _LC = tf.log_critical
+    global USE_LAZY
     USE_LAZY = True
 
 
-def install(domain, lazy=False):
+def install(domain):
     """Install a _() function using the given translation domain.
 
     Given a translation domain, install a _() function using gettext's
@@ -170,26 +163,14 @@ def install(domain, lazy=False):
     a translation-domain-specific environment variable (e.g.
     NOVA_LOCALEDIR).
 
+    Note that to enable lazy translation, enable_lazy must be
+    called.
+
     :param domain: the translation domain
-    :param lazy: indicates whether or not to install the lazy _() function.
-                 The lazy _() introduces a way to do deferred translation
-                 of messages by installing a _ that builds Message objects,
-                 instead of strings, which can then be lazily translated into
-                 any available locale.
     """
-    if lazy:
-        from six import moves
-        tf = TranslatorFactory(domain, lazy=True)
-        moves.builtins.__dict__['_'] = tf.primary
-    else:
-        localedir = '%s_LOCALEDIR' % domain.upper()
-        if six.PY3:
-            gettext.install(domain,
-                            localedir=os.environ.get(localedir))
-        else:
-            gettext.install(domain,
-                            localedir=os.environ.get(localedir),
-                            unicode=True)
+    from six import moves
+    tf = TranslatorFactory(domain)
+    moves.builtins.__dict__['_'] = tf.primary
 
 
 class Message(six.text_type):
diff --git a/tests/unit/test_gettext.py b/tests/unit/test_gettext.py
index 47490534..1d9d6ad2 100644
--- a/tests/unit/test_gettext.py
+++ b/tests/unit/test_gettext.py
@@ -39,6 +39,7 @@ class GettextTest(test_base.BaseTestCase):
         self.mox = moxfixture.mox
         # remember so we can reset to it later
         self._USE_LAZY = gettextutils.USE_LAZY
+        gettextutils.USE_LAZY = False
 
     def tearDown(self):
         # reset to value before test
@@ -59,28 +60,14 @@ class GettextTest(test_base.BaseTestCase):
         gettextutils.install('blaa')
         self.assertTrue(isinstance(_('A String'), six.text_type))  # noqa
 
-        gettextutils.install('blaa', lazy=True)
+    def test_gettextutils_install_with_enable(self):
+        gettextutils.install('blaa')
+        self.assertTrue(isinstance(_('A String'), six.text_type))  # noqa
+
+        gettextutils.enable_lazy()
         self.assertTrue(isinstance(_('A Message'),  # noqa
                                    gettextutils.Message))
 
-    def test_gettext_install_looks_up_localedir(self):
-        with mock.patch('os.environ.get') as environ_get:
-            with mock.patch('gettext.install') as gettext_install:
-                environ_get.return_value = '/foo/bar'
-
-                gettextutils.install('blaa')
-
-                environ_get.assert_called_once_with('BLAA_LOCALEDIR')
-                if six.PY3:
-                    gettext_install.assert_called_once_with(
-                        'blaa',
-                        localedir='/foo/bar')
-                else:
-                    gettext_install.assert_called_once_with(
-                        'blaa',
-                        localedir='/foo/bar',
-                        unicode=True)
-
     def test_get_available_languages(self):
         # All the available languages for which locale data is available
         def _mock_locale_identifiers():
@@ -718,9 +705,21 @@ class TranslationHandlerTestCase(test_base.BaseTestCase):
 
 class TranslatorFactoryTest(test_base.BaseTestCase):
 
+    def setUp(self):
+        super(TranslatorFactoryTest, self).setUp()
+        # remember so we can reset to it later
+        self._USE_LAZY = gettextutils.USE_LAZY
+        gettextutils.USE_LAZY = False
+
+    def tearDown(self):
+        # reset to value before test
+        gettextutils.USE_LAZY = self._USE_LAZY
+        super(TranslatorFactoryTest, self).tearDown()
+
     def test_lazy(self):
         with mock.patch.object(gettextutils, 'Message') as msg:
-            tf = gettextutils.TranslatorFactory('domain', lazy=True)
+            tf = gettextutils.TranslatorFactory('domain')
+            gettextutils.enable_lazy()
             tf.primary('some text')
             msg.assert_called_with('some text', domain='domain')
 
@@ -731,7 +730,7 @@ class TranslatorFactoryTest(test_base.BaseTestCase):
                 translation.return_value = trans
                 trans.gettext.side_effect = AssertionError(
                     'should have called ugettext')
-                tf = gettextutils.TranslatorFactory('domain', lazy=False)
+                tf = gettextutils.TranslatorFactory('domain')
                 tf.primary('some text')
                 trans.ugettext.assert_called_with('some text')
 
@@ -742,14 +741,14 @@ class TranslatorFactoryTest(test_base.BaseTestCase):
                 translation.return_value = trans
                 trans.ugettext.side_effect = AssertionError(
                     'should have called gettext')
-                tf = gettextutils.TranslatorFactory('domain', lazy=False)
+                tf = gettextutils.TranslatorFactory('domain')
                 tf.primary('some text')
                 trans.gettext.assert_called_with('some text')
 
     def test_log_level_domain_name(self):
         with mock.patch.object(gettextutils.TranslatorFactory,
                                '_make_translation_func') as mtf:
-            tf = gettextutils.TranslatorFactory('domain', lazy=False)
+            tf = gettextutils.TranslatorFactory('domain')
             tf._make_log_translation_func('mylevel')
             mtf.assert_called_with('domain-log-mylevel')
 
@@ -765,7 +764,7 @@ class LogLevelTranslationsTest(test_base.BaseTestCase):
     def test(self):
         with mock.patch.object(gettextutils.TranslatorFactory,
                                '_make_translation_func') as mtf:
-            tf = gettextutils.TranslatorFactory('domain', lazy=False)
+            tf = gettextutils.TranslatorFactory('domain')
             getattr(tf, 'log_%s' % self.level)
             mtf.assert_called_with('domain-log-%s' % self.level)