Ticket #19160: 19160-5.diff

diff --git a/django/utils/translation/__init__.py b/django/utils/translation/__init__.py
index f3cc634..9333ba8 100644
--- a/django/utils/translation/__init__.py
+++ b/django/utils/translation/__init__.py
@@ -80,11 +80,42 @@ def npgettext(context, singular, plural, number):
     return _trans.npgettext(context, singular, plural, number)
 
 gettext_lazy = lazy(gettext, str)
-ngettext_lazy = lazy(ngettext, str)
 ugettext_lazy = lazy(ugettext, six.text_type)
-ungettext_lazy = lazy(ungettext, six.text_type)
 pgettext_lazy = lazy(pgettext, six.text_type)
-npgettext_lazy = lazy(npgettext, six.text_type)
+
+
+def lazy_number(func, resultclasses, number=None, **kwargs):
+    if isinstance(number, int):
+        kwargs['number'] = number
+        proxy = lazy(func, *resultclasses)(**kwargs)
+    else:
+        proxy = lazy(func, *resultclasses)(**kwargs)
+        def mod(self, rhs):
+            if isinstance(rhs, dict) and number:
+                number_value = rhs[number]
+            else:
+                number_value = rhs
+            self._proxy____kw['number'] = number_value
+            result = original_mod(self, rhs)
+            del self._proxy____kw['number']
+            return result
+        original_mod = getattr(proxy.__class__, '__mod__')
+        setattr(proxy.__class__, '__mod__', mod)
+    return proxy
+
+def ngettext_lazy(singular, plural, number=None):
+    return lazy_number(
+        ngettext, [str], singular=singular, plural=plural, number=number)
+
+def ungettext_lazy(singular, plural, number=None):
+    return lazy_number(
+        ungettext, [six.text_type], singular=singular, plural=plural, number=number)
+
+def npgettext_lazy(context, singular, plural, number=None):
+    return lazy_number(
+        npgettext, [six.text_type], context=context, singular=singular, plural=plural, number=number)
+
+
 
 def activate(language):
     return _trans.activate(language)
diff --git a/docs/topics/i18n/translation.txt b/docs/topics/i18n/translation.txt
index 0b13ea1..82199ba 100644
--- a/docs/topics/i18n/translation.txt
+++ b/docs/topics/i18n/translation.txt
@@ -408,6 +408,33 @@ convert them to strings, because they should be converted as late as possible
 (so that the correct locale is in effect). This necessitates the use of the
 helper function described next.
 
+Lazy translations and plural
+----------------------------
+
+.. versionadded:: 1.5
+
+When using lazy translation for a plural string (``[u]n[p]gettext_lazy``), you
+generally don't know the ``number`` argument at the time of the string
+definition. Therefore, you are authorized to pass a dictionary key name in place
+of an integer as the ``number`` argument. Then, when the string is effectively
+translated with a placeholders dictionary, the ``number`` argument will get
+substituted by the value of the key in the dictionary. Alternatively, if the
+string contains only one unnamed placeholder, you can also omit passing the
+``number`` argument at all. For example::
+
+    class MyForm(forms.Form):
+        error1_message = ungettext_lazy("You only provided %(num)d argument",
+            "You only provided %(num)d arguments", 'num')
+        error2_message = ungettext_lazy("You provided %d argument",
+            "You provided %d arguments")
+
+        def clean(self):
+            if err_1:
+                raise forms.ValidationError(self.error1_message % {'num': number})
+            if err_2:
+                raise forms.ValidationError(self.error2_message % number)
+
+
 Joining strings: string_concat()
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.mo b/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.mo
index f825e3918b7fd74b7af37e55e704b260101367b7..b43f2824584826898add21d2c013063b1a869186 100644
GIT binary patch
delta 594
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delta 327
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diff --git a/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.po b/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.po
index a471d38..e138bb0 100644
--- a/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.po
+++ b/tests/regressiontests/i18n/other/locale/de/LC_MESSAGES/django.po
@@ -35,6 +35,18 @@ msgid "May"
 msgstr "Kann"
 
 #: models.py:11
+msgid "%d good result"
+msgid_plural "%d good results"
+msgstr[0] "%d gutes Resultat"
+msgstr[1] "%d guten Resultate"
+
+#: models.py:11
+msgid "Hi %(name)s, %(num)d good result"
+msgid_plural "Hi %(name)s, %(num)d good results"
+msgstr[0] "Hallo %(name)s, %(num)d gutes Resultat"
+msgstr[1] "Hallo %(name)s, %(num)d guten Resultate"
+
+#: models.py:11
 msgctxt "search"
 msgid "%d result"
 msgid_plural "%d results"
@@ -75,4 +87,4 @@ msgstr "Es gibt %(num_comments)s Kommentare"
 #: models.py:23
 msgctxt "other comment count"
 msgid "There are %(num_comments)s comments"
-msgstr "Andere: Es gibt %(num_comments)s Kommentare"
\ No newline at end of file
+msgstr "Andere: Es gibt %(num_comments)s Kommentare"
diff --git a/tests/regressiontests/i18n/tests.py b/tests/regressiontests/i18n/tests.py
index 44d84f9..1aa7fd9 100644
--- a/tests/regressiontests/i18n/tests.py
+++ b/tests/regressiontests/i18n/tests.py
@@ -23,7 +23,7 @@ from django.utils.safestring import mark_safe, SafeBytes, SafeString, SafeText
 from django.utils import six
 from django.utils.six import PY3
 from django.utils.translation import (ugettext, ugettext_lazy, activate,
-    deactivate, gettext_lazy, pgettext, npgettext, to_locale,
+    deactivate, gettext_lazy, ungettext_lazy, pgettext, npgettext, to_locale,
     get_language_info, get_language, get_language_from_request, trans_real)
 
 
@@ -51,7 +51,6 @@ extended_locale_paths = settings.LOCALE_PATHS + (
 )
 
 class TranslationTests(TestCase):
-
     def test_override(self):
         activate('de')
         with translation.override('pl'):
@@ -95,6 +94,20 @@ class TranslationTests(TestCase):
         self.assertEqual(six.text_type(s2), "test")
 
     @override_settings(LOCALE_PATHS=extended_locale_paths)
+    def test_ungettext_lazy(self):
+        s = ungettext_lazy("%d good result", "%d good result")
+        with translation.override('de'):
+            self.assertEqual(s % 1, "1 gutes Resultat")
+            self.assertEqual(s % 4, "4 guten Resultate")
+
+        s1 = ungettext_lazy("Hi %(name)s, %(num)d good result", "Hi %(name)s, %(num)d good results", 4)
+        s2 = ungettext_lazy("Hi %(name)s, %(num)d good result", "Hi %(name)s, %(num)d good results", 'num')
+        with translation.override('de'):
+            self.assertEqual(s1 % {'num': 4, 'name': 'Jim'}, "Hallo Jim, 4 guten Resultate")
+            self.assertEqual(s2 % {'name': 'Jim', 'num': 1}, "Hallo Jim, 1 gutes Resultat")
+            self.assertEqual(s2 % {'name': 'Jim', 'num': 5}, "Hallo Jim, 5 guten Resultate")
+
+    @override_settings(LOCALE_PATHS=extended_locale_paths)
     def test_pgettext(self):
         trans_real._active = local()
         trans_real._translations = {}
-- 
1.8.0.2