Fix translated form labels using current language (#108)

Fixes #87

modeltrans/fields.py

@@ -10,6 +10,7 @@
     build_localized_fieldname,
     get_instance_field_value,
     get_language,
+    get_translated_field_label,
 )
 
 SUPPORTED_FIELDS = (fields.CharField, fields.TextField)
@@ -76,9 +77,9 @@ def contribute_to_class(self, cls, name):
         self.column = None
 
         # Use a translated verbose name:
-        translated_field_name = gettext(self.original_field.verbose_name)
+        translated_field_name = self.original_field.verbose_name
         if self.language is not None:
-            translated_field_name += " ({})".format(self.language.upper())
+            translated_field_name = get_translated_field_label(translated_field_name, self.language)
         self.verbose_name = translated_field_name
 
         setattr(cls, name, self)

modeltrans/utils.py

@@ -2,6 +2,7 @@
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.fields.json import KeyTransform
 from django.db.models.lookups import Transform
+from django.utils.functional import keep_lazy_text
 from django.utils.translation import get_language as _get_language
 
 from .conf import get_available_languages, get_default_language
@@ -24,6 +25,11 @@ def split_translated_fieldname(field_name):
     return (field_name[0:_pos], field_name[_pos + 1 :])
 
 
+@keep_lazy_text
+def get_translated_field_label(original_label, lang):
+    return original_label + " ({})".format(lang.upper())
+
+
 def build_localized_fieldname(field_name, lang, ignore_default=False):
     if lang == "id":
         # The 2-letter Indonesian language code is problematic with the

tests/app/locale/de/LC_MESSAGES/django.po

@@ -0,0 +1,23 @@
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2024-04-07 11:39+0000\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <[email protected]>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+#: app/models.py:203
+msgid "title of the post"
+msgstr "Titel des Beitrags"

tests/app/locale/fr/LC_MESSAGES/django.po

@@ -0,0 +1,23 @@
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2024-04-07 11:39+0000\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <[email protected]>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\n"
+
+#: app/models.py:203
+msgid "title of the post"
+msgstr "Titre de l'article"

tests/app/models.py

@@ -1,4 +1,5 @@
 from django.db import models
+from django.utils.translation import gettext_lazy
 
 from modeltrans.conf import get_default_language
 from modeltrans.fields import TranslationField
@@ -198,7 +199,10 @@ def __str__(self):
 
 
 class Post(models.Model):
-    title = models.CharField(max_length=255)
+    title = models.CharField(
+        verbose_name=gettext_lazy("title of the post"),
+        max_length=255,
+    )
     is_published = models.BooleanField(default=False)
 
     i18n = TranslationField(fields=("title",))

tests/test_forms.py

@@ -240,6 +240,26 @@ def test_setting_of_field_properties(self):
             self.assertEqual(title_fr_field.required, True)
             self.assertEqual(title_fr_field.widget.__class__, forms.widgets.Textarea)
 
+    def test_translated_field_labels(self):
+        """Test that a field's verbose_name is translated to the currently active language."""
+        form_cls = modelform_factory(Post, fields="__all__")
+        form = form_cls()
+        self.assertEqual(form.fields["title"].label, "Title of the post")
+        self.assertEqual(form.fields["title_de"].label, "Title of the post (DE)")
+        self.assertEqual(form.fields["title_fr"].label, "Title of the post (FR)")
+
+        with override("de"):
+            form = form_cls()
+            self.assertEqual(form.fields["title"].label, "Titel des Beitrags")
+            self.assertEqual(form.fields["title_de"].label, "Titel des Beitrags (DE)")
+            self.assertEqual(form.fields["title_fr"].label, "Titel des Beitrags (FR)")
+
+        with override("fr"):
+            form = form_cls()
+            self.assertEqual(form.fields["title"].label, "Titre de l'article")
+            self.assertEqual(form.fields["title_de"].label, "Titre de l'article (DE)")
+            self.assertEqual(form.fields["title_fr"].label, "Titre de l'article (FR)")
+
     def test_form_initial_values(self):
         challenge = Challenge.objects.create(title="english", title_fr="french")
         initial_data = {