[1.9.x] Fixed #26341 -- Fixed makemessages breaking location comments for HTML files

Thanks Sylvain Garancher for the report and Veranika Sabiashchanskaya for the
initial patch.
Backport of b16b124996 from master.

django/core/management/commands/makemessages.py

@@ -147,13 +147,18 @@ class BuildFile(object):
         # Remove '.py' suffix
         if os.name == 'nt':
             # Preserve '.\' prefix on Windows to respect gettext behavior
-            old = '#: ' + self.work_path
-            new = '#: ' + self.path
+            old_path = self.work_path
+            new_path = self.path
         else:
-            old = '#: ' + self.work_path[2:]
-            new = '#: ' + self.path[2:]
+            old_path = self.work_path[2:]
+            new_path = self.path[2:]
 
-        return msgs.replace(old, new)
+        return re.sub(
+            r'^(#: .*)(' + re.escape(old_path) + r')',
+            r'\1' + new_path,
+            msgs,
+            flags=re.MULTILINE
+        )
 
     def cleanup(self):
         """

docs/releases/1.9.6.txt

@@ -27,3 +27,6 @@ Bugfixes
 
 * Restored conversion of an empty string to null when saving values of
   ``GenericIPAddressField`` on SQLite and MySQL (:ticket:`26557`).
+
+* Fixed a ``makemessages`` regression where temporary ``.py`` extensions were
+  leaked in source file paths (:ticket:`26341`).

tests/i18n/commands/__init__.py

@@ -12,3 +12,6 @@ number = 3
 dummy3 = ungettext("%(number)s Foo", "%(number)s Foos", number) % {'number': number}
 
 dummy4 = _('Size')
+
+# This string is intentionally duplicated in test.html
+dummy5 = _('This literal should be included.')

tests/i18n/commands/templates/test.html

@@ -70,6 +70,9 @@ continued here.{% endcomment %}
 {% trans "Translatable literal #7.1g"|add:2 context "context #7.1g" as var %}
 {% trans "Translatable literal #7.1h" | add:"foo" | add:2 context "context #7.1h" as var %}
 
+<!-- Source file inside a msgid, should be left as-is. -->
+{% trans "#: templates/test.html.py" %}
+
 {% blocktrans context "Special blocktrans context #1" %}Translatable literal #8a{% endblocktrans %}
 {% blocktrans count 2 context "Special blocktrans context #2" %}Translatable literal #8b-singular{% plural %}Translatable literal #8b-plural{% endblocktrans %}
 {% blocktrans context "Special blocktrans context #3" count 2 %}Translatable literal #8c-singular{% plural %}Translatable literal #8c-plural{% endblocktrans %}

tests/i18n/test_extraction.py

@@ -635,8 +635,19 @@ class LocationCommentsTests(ExtractorTests):
         # #16903 -- Standard comment with source file relative path should be present
         self.assertLocationCommentPresent(self.PO_FILE, 'Translatable literal #6b', 'templates', 'test.html')
 
-        # #21208 -- Leaky paths in comments on Windows e.g. #: path\to\file.html.py:123
-        self.assertLocationCommentNotPresent(self.PO_FILE, None, 'templates', 'test.html.py')
+    def test_location_comments_for_templatized_files(self):
+        """
+        Ensure no leaky paths in comments, e.g. #: path\to\file.html.py:123
+        Refs #21209/#26341.
+        """
+        os.chdir(self.test_dir)
+        management.call_command('makemessages', locale=[LOCALE], 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.assertMsgId('#: templates/test.html.py', po_contents)
+        self.assertLocationCommentNotPresent(self.PO_FILE, None, '.html.py')
+        self.assertLocationCommentPresent(self.PO_FILE, 5, 'templates', 'test.html')
 
 
 class KeepPotFileExtractorTests(ExtractorTests):