Fix duplicate tag error (#65)

bookmarks/services/tags.py

@@ -1,3 +1,4 @@
+import logging
 import operator
 from typing import List
 
@@ -7,6 +8,8 @@ from django.utils import timezone
 from bookmarks.models import Tag
 from bookmarks.utils import unique
 
+logger = logging.getLogger(__name__)
+
 
 def get_or_create_tags(tag_names: List[str], user: User):
     tags = [get_or_create_tag(tag_name, user) for tag_name in tag_names]
@@ -21,3 +24,14 @@ def get_or_create_tag(name: str, user: User):
         tag.date_added = timezone.now()
         tag.save()
         return tag
+    except Tag.MultipleObjectsReturned:
+        # Legacy databases might contain duplicate tags with different capitalization
+        first_tag = Tag.objects.filter(name__iexact=name, owner=user).first()
+        message = (
+            "Found multiple tags for the name '{0}' with different capitalization. "
+            "Using the first tag with the name '{1}'. "
+            "Since v.1.2 tags work case-insensitive, which means duplicates of the same name are not allowed anymore. "
+            "To solve this error remove the duplicate tag in admin."
+        ).format(name, first_tag.name)
+        logger.error(message)
+        return first_tag

bookmarks/tests/test_tags_service.py

@@ -42,6 +42,13 @@ class TagTestCase(TestCase):
         self.assertEqual(len(tags), 1)
         self.assertEqual(first_tag.id, second_tag.id)
 
+    def test_get_or_create_tag_should_handle_legacy_dbs_with_existing_duplicates(self):
+        Tag.objects.create(name='book', date_added=timezone.now(), owner=self.user)
+        Tag.objects.create(name='Book', date_added=timezone.now(), owner=self.user)
+        first_tag = get_or_create_tag('Book', self.user)
+
+        self.assertEqual(first_tag.id, first_tag.id)
+
     def test_get_or_create_tags_should_return_tags(self):
         books_tag = get_or_create_tag('Book', self.user)
         movies_tag = get_or_create_tag('Movie', self.user)