Feature: Replace Whoosh with tantivy search backend (#12471)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Antoine Mérino <3023499+Merinorus@users.noreply.github.com>

src/documents/migrations/0017_migrate_fulltext_query_field_prefixes.py

@@ -0,0 +1,39 @@
+import re
+
+from django.db import migrations
+
+# Matches "note:" when NOT preceded by a word character or dot.
+# This avoids false positives like "denote:" or already-migrated "notes.note:".
+# Handles start-of-string, whitespace, parentheses, +/- operators per Whoosh syntax.
+_NOTE_RE = re.compile(r"(?<![.\w])note:")
+
+# Same logic for "custom_field:" -> "custom_fields.value:"
+_CUSTOM_FIELD_RE = re.compile(r"(?<![.\w])custom_field:")
+
+
+def migrate_fulltext_query_field_prefixes(apps, schema_editor):
+    SavedViewFilterRule = apps.get_model("documents", "SavedViewFilterRule")
+
+    # rule_type 20 = "fulltext query" — value is a search query string
+    for rule in SavedViewFilterRule.objects.filter(rule_type=20).exclude(
+        value__isnull=True,
+    ):
+        new_value = _NOTE_RE.sub("notes.note:", rule.value)
+        new_value = _CUSTOM_FIELD_RE.sub("custom_fields.value:", new_value)
+
+        if new_value != rule.value:
+            rule.value = new_value
+            rule.save(update_fields=["value"])
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("documents", "0016_sha256_checksums"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            migrate_fulltext_query_field_prefixes,
+            migrations.RunPython.noop,
+        ),
+    ]