Handle text field clearing when syncing

wagtail_localize/fields.py

@@ -61,16 +61,24 @@ class TranslatableField(BaseTranslatableField):
     def is_translated(self, obj):
         return True
 
-    def is_synchronized(self, obj):
-        field = self.get_field(obj.__class__)
+    def is_synchronized(self, source):
+        field = self.get_field(source.__class__)
 
         # Child relations should all be synchronised before translation
-        if isinstance(field, (models.ManyToOneRel)) and isinstance(
+        if isinstance(field, models.ManyToOneRel) and isinstance(
             field.remote_field, ParentalKey
         ):
             return True
 
-        # Streamfields need to be re-synchronised before translation so the structure and non-translatable content is copied over
+        # We have a text field that has been cleared so we should mark it as synchronised
+        if (
+            isinstance(field, (RichTextField, models.TextField, models.CharField))
+            and getattr(source, field.attname) == ""
+        ):
+            return True
+
+        # Streamfields need to be re-synchronised before translation so
+        # the structure and non-translatable content is copied over
         return isinstance(field, StreamField)
 
     def __repr__(self):
@@ -245,7 +253,7 @@ def copy_synchronised_fields(source, target):
         if translatable_field.is_synchronized(source):
             field = translatable_field.get_field(target.__class__)
 
-            if isinstance(field, (models.ManyToOneRel)) and isinstance(
+            if isinstance(field, models.ManyToOneRel) and isinstance(
                 field.remote_field, ParentalKey
             ):
                 # Use modelcluster's copy_child_relation for child relations

wagtail_localize/tests/test_update_translations.py

@@ -206,6 +206,7 @@ def setUp(self):
             title="Blog post",
             slug="blog-post",
             test_charfield="Test content",
+            test_richtextfield="<p>rich text</p>",
         )
 
         self.en_snippet = TestSnippet.objects.create(field="Test snippet")
@@ -351,6 +352,30 @@ def test_post_update_page_translation_with_publish_translations(self):
         self.fr_blog_post.refresh_from_db()
         self.assertEqual(self.fr_blog_post.test_charfield, "Edited blog post")
 
+    def test_post_update_page_translation_with_publish_translations_and_cleared_text_field(
+        self,
+    ):
+        self.en_blog_post.test_charfield = ""
+        self.en_blog_post.test_richtextfield = ""
+        self.en_blog_post.save_revision().publish()
+
+        response = self.client.post(
+            reverse(
+                "wagtail_localize:update_translations",
+                args=[self.page_source.id],
+            ),
+            {"publish_translations": "on"},
+        )
+
+        self.assertRedirects(
+            response, reverse("wagtailadmin_explore", args=[self.en_blog_index.id])
+        )
+
+        # The FR version should be updated
+        self.fr_blog_post.refresh_from_db()
+        self.assertEqual(self.fr_blog_post.test_charfield, "")
+        self.assertEqual(self.fr_blog_post.test_richtextfield, "")
+
     def test_post_update_snippet_translation(self):
         self.en_snippet.field = "Edited snippet"
         self.en_snippet.save()