Fixed #17375 -- Changed makemessages to use xgettext with --files-from

Changed the way makemessages invokes xgettext from one call per
translatable file to one call per locale directory (using --files-from).
This allows to avoid https://savannah.gnu.org/bugs/index.php?35027 and,
as a positive side effect, speeds up localization build.

docs/releases/1.9.txt

@@ -380,6 +380,9 @@ Internationalization
   project and it will find all the app message files that were created by
   :djadmin:`makemessages`.
 
+* :djadmin:`makemessages` now calls xgettext once per locale directory rather
+  than once per translatable file. This speeds up localization builds.
+
 * :ttag:`blocktrans` supports assigning its output to a variable using
   ``asvar``.
 

tests/i18n/commands/templates/plural.djtpl

@@ -4,3 +4,5 @@ This file has a literal with plural forms. When processed first, makemessages
 shouldn't create a .po file with duplicate `Plural-Forms` headers
 {% endcomment %}
 {% blocktrans count number=3 %}{{ number }} Bar{% plural %}{{ number }} Bars{% endblocktrans %}
+
+{% trans 'First `trans`, then `blocktrans` with a plural' %}

tests/i18n/commands/templates/test.html

@@ -80,3 +80,9 @@ continued here.{% endcomment %}
   should be trimmed.
 {% endblocktrans %}
 {% trans "I'm on line 82" %}
+
+{% blocktrans trimmed count counter=mylist|length %}
+First `trans`, then `blocktrans` with a plural
+{% plural %}
+Plural for a `trans` and `blocktrans` collision case
+{% endblocktrans %}

tests/i18n/test_extraction.py

@@ -80,6 +80,9 @@ class ExtractorTests(SimpleTestCase):
     def assertMsgId(self, msgid, haystack, use_quotes=True):
         return self._assertPoKeyword('msgid', msgid, haystack, use_quotes=use_quotes)
 
+    def assertMsgIdPlural(self, msgid, haystack, use_quotes=True):
+        return self._assertPoKeyword('msgid_plural', msgid, haystack, use_quotes=use_quotes)
+
     def assertMsgStr(self, msgstr, haystack, use_quotes=True):
         return self._assertPoKeyword('msgstr', msgstr, haystack, use_quotes=use_quotes)
 
@@ -525,6 +528,21 @@ class CopyPluralFormsExtractorTests(ExtractorTests):
             found = re.findall(r'^(?P<value>"Plural-Forms.+?\\n")\s*$', po_contents, re.MULTILINE | re.DOTALL)
             self.assertEqual(1, len(found))
 
+    def test_trans_and_plural_blocktrans_collision(self):
+        """
+        Ensures a correct workaround for the gettext bug when handling a literal
+        found inside a {% trans %} tag and also in another file inside a
+        {% blocktrans %} with a plural (#17375).
+        """
+        os.chdir(self.test_dir)
+        management.call_command('makemessages', locale=[LOCALE], extensions=['html', 'djtpl'], verbosity=0)
+        self.assertTrue(os.path.exists(self.PO_FILE))
+        with open(self.PO_FILE, 'r') as fp:
+            po_contents = force_text(fp.read())
+            self.assertNotIn("#-#-#-#-#  django.pot (PACKAGE VERSION)  #-#-#-#-#\\n", po_contents)
+            self.assertMsgId('First `trans`, then `blocktrans` with a plural', po_contents)
+            self.assertMsgIdPlural('Plural for a `trans` and `blocktrans` collision case', po_contents)
+
 
 class NoWrapExtractorTests(ExtractorTests):