misc(variants): change index to TextField and remove OperationalError (#18262)

* Change index to TextField and remove OperationalError.
* Use MD5 index for variants.

Author: amCap1712

weblate/trans/migrations/0066_alter_variant_key.py

@@ -0,0 +1,35 @@
+# Copyright © Michal Čihař <michal@weblate.org>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Generated by Django 5.2.11 on 2026-02-28 00:00
+
+from django.db import migrations, models
+from django.db.models.functions import MD5
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("trans", "0065_alter_change_action"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="variant",
+            name="key",
+            field=models.TextField(),
+        ),
+        migrations.AlterUniqueTogether(
+            name="variant",
+            unique_together=set(),
+        ),
+        migrations.AddConstraint(
+            model_name="variant",
+            constraint=models.UniqueConstraint(
+                MD5("key"),
+                models.F("component"),
+                models.F("variant_regex"),
+                name="trans_variant_unique_key_md5",
+            ),
+        ),
+    ]

weblate/trans/models/component.py

@@ -26,7 +26,8 @@
 )
 from django.core.validators import MaxValueValidator
 from django.db import IntegrityError, models, transaction
-from django.db.models import Count, F, Q
+from django.db.models import Count, F, Q, Value
+from django.db.models.functions import MD5
 from django.db.models.signals import m2m_changed
 from django.dispatch import receiver
 from django.utils.functional import cached_property
@@ -3715,10 +3716,10 @@ def update_variants(self, updated_units=None) -> None:
             for unit in units.iterator():
                 if variant_re.findall(unit.context):
                     key = variant_re.sub("", unit.context)
-                    if key in variant_updates:
-                        variant = variant_updates[key][0]
-                    else:
-                        variant = Variant.objects.get_or_create(
+                    if key not in variant_updates:
+                        variant = Variant.objects.filter(
+                            key__md5=MD5(Value(key))
+                        ).get_or_create(
                             key=key, component=self, variant_regex=self.variant_regex
                         )[0]
                         variant_updates[key] = (variant, [])

weblate/trans/models/unit.py

@@ -808,9 +808,9 @@ def update_variants(self) -> None:
 
         # Add new variant
         if new_variant:
-            variant = Variant.objects.get_or_create(
-                key=new_variant, component=component, variant_regex=""
-            )[0]
+            variant = Variant.objects.filter(
+                key__md5=MD5(Value(new_variant))
+            ).get_or_create(key=new_variant, component=component, variant_regex="")[0]
             variant.defining_units.add(self)
 
         # Update variant links

weblate/trans/models/variant.py

@@ -3,8 +3,9 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 from django.db import models
+from django.db.models.functions import MD5
 
-from weblate.trans.defines import VARIANT_KEY_LENGTH, VARIANT_REGEX_LENGTH
+from weblate.trans.defines import VARIANT_REGEX_LENGTH
 from weblate.trans.fields import RegexField
 
 
@@ -13,15 +14,20 @@ class Variant(models.Model):
         "trans.Component", on_delete=models.deletion.CASCADE, db_index=False
     )
     variant_regex = RegexField(max_length=VARIANT_REGEX_LENGTH, blank=True)
-    # This really should be a TextField, but it does not work with unique
-    # index and MySQL
-    key = models.CharField(max_length=VARIANT_KEY_LENGTH)
+    key = models.TextField()
     defining_units = models.ManyToManyField(
         "trans.Unit", related_name="defined_variants"
     )
 
     class Meta:
-        unique_together = (("component", "key", "variant_regex"),)
+        constraints = [  # noqa: RUF012
+            models.UniqueConstraint(
+                MD5("key"),
+                "component",
+                "variant_regex",
+                name="trans_variant_unique_key_md5",
+            ),
+        ]
         verbose_name = "variant definition"
         verbose_name_plural = "variant definitions"
 

weblate/utils/search.py

@@ -16,7 +16,7 @@
 from dateutil.parser import parse as dateutil_parse
 from django.db import transaction
 from django.db.models import Count, Exists, F, OuterRef, Q, Value
-from django.db.utils import DataError, OperationalError
+from django.db.utils import DataError
 from django.http import Http404
 from django.utils import timezone
 from django.utils.translation import gettext
@@ -476,8 +476,7 @@ def as_query(self, context: dict) -> Q:
                     Unit.objects.annotate(test=Value("")).filter(
                         test__trgm_regex=match.expr
                     ).exists()
-                except (DataError, OperationalError) as error:
-                    # PostgreSQL raises DataError, MySQL OperationalError
+                except DataError as error:
                     raise SearchQueryError(
                         gettext("Invalid regular expression: {}").format(error)
                     ) from error