Merge pull request #797 from jazzband/unicode-slugify

Preserve unicode when slugifying by default

Author: rtpg

CHANGELOG.rst

@@ -4,7 +4,26 @@ Changelog
 (Unreleased)
 ~~~~~~~~~~~~
 
-* Drop Django 2.2 support.
+* **Backwards incompatible:** Tag slugification used to silently strip non-ASCII characters
+  from the tag name to make the slug. This leads to a lot of confusion for anyone using
+  languages with non-latin alphabets, as well as weird performance issues.
+
+  Tag slugification will now, by default, maintain unicode characters as-is during
+  slugification. This will lead to less surprises, but might cause issues for you if you are
+  expecting all of your tag slugs to fit within a regex like ``[a-zA-Z0-9]`` (for example in
+  URL routing configurations).
+
+  Generally speaking, this should not require action on your part as a library user, as
+  existing tag slugs are persisted in the database, and only new tags will receive the
+  enhanced unicode-compatible slug.
+
+  If you wish to maintain the old stripping behavior, set the setting
+  ``TAGGIT_STRIP_UNICODE_WHEN_SLUGIFYING`` to ``True``.
+
+  As a reminder, custom tag models can easily customize slugification behavior by overriding
+  the ``slugify`` method to your business needs.
+
+`` Drop Django 2.2 support.
 
 2.1.0 (2022-01-24)
 ~~~~~~~~~~~~~~~~~~

docs/faq.rst

@@ -13,7 +13,8 @@ Frequently Asked Questions
 
 
  One way to handle this is with post-generation hooks::
-    class ProductFactory(DjangoModelFactory):
+
+   class ProductFactory(DjangoModelFactory):
         # Rest of the stuff
 
         @post_generation

docs/getting_started.rst

@@ -27,3 +27,23 @@ And then to any model you want tagging on do the following::
     If you want ``django-taggit`` to be **CASE-INSENSITIVE** when looking up existing tags, you'll have to set ``TAGGIT_CASE_INSENSITIVE`` (in ``settings.py`` or wherever you have your Django settings) to ``True`` (``False`` by default)::
 
       TAGGIT_CASE_INSENSITIVE = True
+
+
+Settings
+--------
+
+The following Django-level settings affect the behavior of the library
+
+* ``TAGGIT_CASE_INSENSITIVE``
+
+  When set to ``True``, tag lookups will be case insensitive. This defaults to ``False``.
+
+`` ``TAGGIT_STRIP_UNICODE_WHEN_SLUGIFYING``
+  When this is set to ``True``, tag slugs will be limited to ASCII characters. In this case, if you also have ```unidecode`` installed,
+  then tag sluggification will transform a tag like ``あい　うえお`` to ``ai-ueo``.
+  If you do not have ``unidecode`` installed, then you will usually be outright stripping unicode, meaning that something like ``helloあい`` will be slugified as ``hello``.
+
+  This value defaults to ``False``, meaning that unicode is preserved in slugification.
+
+  Because the behavior when ``True`` is set leads to situations where
+  slugs can be entirely stripped to an empty string, we recommend not activating this.

taggit/migrations/0005_auto_20220424_2025.py

@@ -0,0 +1,20 @@
+# Generated by Django 2.2.26 on 2022-04-24 20:25
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("taggit", "0004_alter_taggeditem_content_type_alter_taggeditem_tag"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="tag",
+            name="slug",
+            field=models.SlugField(
+                allow_unicode=True, max_length=100, unique=True, verbose_name="slug"
+            ),
+        ),
+    ]

taggit/models.py

@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db import IntegrityError, models, router, transaction
@@ -19,7 +20,10 @@ class TagBase(models.Model):
         verbose_name=pgettext_lazy("A tag name", "name"), unique=True, max_length=100
     )
     slug = models.SlugField(
-        verbose_name=pgettext_lazy("A tag slug", "slug"), unique=True, max_length=100
+        verbose_name=pgettext_lazy("A tag slug", "slug"),
+        unique=True,
+        max_length=100,
+        allow_unicode=True,
     )
 
     def __str__(self):
@@ -71,7 +75,10 @@ def save(self, *args, **kwargs):
             return super().save(*args, **kwargs)
 
     def slugify(self, tag, i=None):
-        slug = slugify(unidecode(tag))
+        if getattr(settings, "TAGGIT_STRIP_UNICODE_WHEN_SLUGIFYING", False):
+            slug = slugify(unidecode(tag))
+        else:
+            slug = slugify(tag, allow_unicode=True)
         if i is not None:
             slug += "_%d" % i
         return slug

tests/test_models.py

@@ -0,0 +1,27 @@
+from django.test import TestCase, override_settings
+
+from tests.models import TestModel
+
+
+class TestSlugification(TestCase):
+    def test_unicode_slugs(self):
+        """
+        Confirm the preservation of unicode in slugification by default
+        """
+        sample_obj = TestModel.objects.create()
+        # a unicode tag will be slugified for space reasons but
+        # unicode-ness will be kept by default
+        sample_obj.tags.add("あい うえお")
+        self.assertEqual([tag.slug for tag in sample_obj.tags.all()], ["あい-うえお"])
+
+    def test_old_slugs(self):
+        """
+        Test that the setting that gives us the old slugification behavior
+        is in place
+        """
+        with override_settings(TAGGIT_STRIP_UNICODE_WHEN_SLUGIFYING=True):
+            sample_obj = TestModel.objects.create()
+            # a unicode tag will be slugified for space reasons but
+            # unicode-ness will be kept by default
+            sample_obj.tags.add("あい うえお")
+            self.assertEqual([tag.slug for tag in sample_obj.tags.all()], [""])