Add codes to unidentifiable catalogue models (#4216)

* Add codes to unidentifiable catalogue models

* Add missing migration

src/oscar/apps/catalogue/abstract_models.py

     COMPARISON_FIELDS = ("pk", "path", "depth")
 
     name = models.CharField(_("Name"), max_length=255, db_index=True)
+    code = NullCharField(
+        _("Code"),
+        max_length=255,
+        blank=True,
+        null=True,
+        unique=True,
+    )
     description = models.TextField(_("Description"), blank=True)
     meta_title = models.CharField(
         _("Meta title"), max_length=255, blank=True, null=True
     """
 
     name = models.CharField(_("Name"), max_length=128)
+    code = NullCharField(
+        _("Unique identifier"),
+        max_length=255,
+        blank=True,
+        null=True,
+        unique=True,
+    )
 
     def __str__(self):
         return self.name
         verbose_name=_("Group"),
     )
     option = models.CharField(_("Option"), max_length=255)
+    code = NullCharField(
+        _("Unique identifier"),
+        max_length=255,
+        blank=True,
+        null=True,
+        unique=True,
+    )
 
     def __str__(self):
         return self.option
         related_name="images",
         verbose_name=_("Product"),
     )
+    code = NullCharField(
+        _("Code"),
+        max_length=255,
+        blank=True,
+        null=True,
+        unique=True,
+    )
     original = models.ImageField(
         _("Original"), upload_to=get_image_upload_path, max_length=255
     )

src/oscar/apps/catalogue/migrations/0027_attributeoption_code_attributeoptiongroup_code_and_more.py

+# Generated by Django 4.2.6 on 2023-12-20 17:10
+
+from django.db import migrations
+import oscar.models.fields
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("catalogue", "0026_predefined_product_options"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="attributeoption",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Unique identifier"
+            ),
+        ),
+        migrations.AddField(
+            model_name="attributeoptiongroup",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Unique identifier"
+            ),
+        ),
+        migrations.AddField(
+            model_name="category",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Code"
+            ),
+        ),
+        migrations.AddField(
+            model_name="productimage",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Code"
+            ),
+        ),
+    ]

tests/_site/apps/catalogue/migrations/0027_attributeoption_code_attributeoptiongroup_code_and_more.py

+# Generated by Django 4.2.6 on 2023-12-20 17:10
+
+from django.db import migrations
+import oscar.models.fields
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("catalogue", "0026_predefined_product_options"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="attributeoption",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Unique identifier"
+            ),
+        ),
+        migrations.AddField(
+            model_name="attributeoptiongroup",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Unique identifier"
+            ),
+        ),
+        migrations.AddField(
+            model_name="category",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Code"
+            ),
+        ),
+        migrations.AddField(
+            model_name="productimage",
+            name="code",
+            field=oscar.models.fields.NullCharField(
+                max_length=255, unique=True, verbose_name="Code"
+            ),
+        ),
+    ]