Fix: Add a new custom delete for parent field in taxontreedefitem

specifyweb/backend/businessrules/migrations/0002_default_unique_rules.py

@@ -56,5 +56,5 @@ class Migration(migrations.Migration):
 
     operations = [
         migrations.RunPython(apply_default_rules,
-                             remove_default_rules, atomic=True),
+                                remove_default_rules, atomic=True),
     ]

specifyweb/backend/businessrules/tests/test_taxontreedefitem.py

@@ -1,6 +1,4 @@
-from django.db.models import ProtectedError
 from specifyweb.specify.tests.test_api import ApiTests
-from ..exceptions import TreeBusinessRuleException
 from specifyweb.specify import models
 
 class TaxonTreeDefItemTests(ApiTests):
@@ -30,5 +28,35 @@ def test_delete_blocked_by_taxon(self):
             name="Animals",
             definition=kingdom.treedef,
             rankid=kingdom.rankid)
-
         animals.delete()
+
+    def test_delete_unused_rank_reparents_children(self):
+        kingdom = self.roottaxontreedefitem.children.create(
+            name="Kingdom",
+            treedef=self.taxontreedef,
+            rankid=self.roottaxontreedefitem.rankid+100)
+        phylum = kingdom.children.create(
+            name="Phylum",
+            treedef=self.taxontreedef,
+            rankid=kingdom.rankid+100)
+
+        models.Taxontreedefitem.objects.filter(id=kingdom.id).delete()
+
+        phylum.refresh_from_db()
+        self.assertEqual(phylum.parent_id, self.roottaxontreedefitem.id)
+        self.assertFalse(models.Taxontreedefitem.objects.filter(id=kingdom.id).exists())
+
+    def test_full_tree_delete_still_cascades(self):
+        kingdom = self.roottaxontreedefitem.children.create(
+            name="Kingdom",
+            treedef=self.taxontreedef,
+            rankid=self.roottaxontreedefitem.rankid+100)
+        kingdom.treeentries.create(
+            parent=self.roottaxon,
+            name="Animals",
+            definition=kingdom.treedef,
+            rankid=kingdom.rankid)
+
+        self.taxontreedef.delete()
+
+        self.assertFalse(models.Taxontreedef.objects.filter(id=self.taxontreedef.id).exists())

specifyweb/frontend/js_src/lib/components/WbToolkit/GeoLocate.tsx

@@ -283,4 +283,4 @@ function getGeoLocateData(
       )
     )
   );
-}
+}

specifyweb/specify/migrations/0047_taxontreedefitem_parent_context_delete.py

@@ -0,0 +1,25 @@
+# Generated by Django 4.2.24 on 2026-07-29
+
+from django.db import migrations, models
+import specifyweb.specify.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('specify', '0046_alter_specifyuser_spprincipals'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='taxontreedefitem',
+            name='parent',
+            field=models.ForeignKey(
+                db_column='ParentItemID',
+                null=True,
+                on_delete=specifyweb.specify.models.delete_taxon_rank_parent_with_context,
+                related_name='children',
+                to='specify.taxontreedefitem',
+            ),
+        ),
+    ]

specifyweb/specify/models.py

@@ -16,6 +16,57 @@ def protect_with_blockers(collector, field, sub_objs, using):
     else:
         return models.PROTECT(collector, field, sub_objs, using)
 
+
+def _get_collector_model_instances(collector, model_name):
+    deleting_models = getattr(collector, 'data', {})
+    for model, objs in deleting_models.items():
+        if getattr(model, '__name__', '').lower() == model_name.lower():
+            return list(objs)
+    return []
+
+
+def _reparent_taxon_rank_children(ranks):
+    rank_list = list(ranks)
+    if not rank_list:
+        return
+
+    deleting_rank_ids = {rank.id for rank in rank_list}
+    for rank in rank_list:
+        Taxontreedefitem.objects.filter(parent_id=rank.id)\
+            .exclude(id__in=deleting_rank_ids)\
+            .update(parent_id=rank.parent_id)
+
+
+def delete_taxon_rank_parent_with_context(collector, field, sub_objs, using):
+    """
+    Use CASCADE while deleting an entire TaxonTreeDef.
+
+    For single-rank deletion, reparent child ranks before deleting so
+    ParentItemID remains valid.
+    """
+    deleting_models = getattr(collector, 'data', {})
+    is_tree_delete = any(
+        getattr(model, '__name__', '').lower() == 'taxontreedef'
+        for model in deleting_models.keys()
+    )
+    if is_tree_delete:
+        return models.CASCADE(collector, field, sub_objs, using)
+
+    processed_ids = getattr(collector, '_taxon_rank_delete_prepared_ids', set())
+    ranks_to_delete = [
+        rank
+        for rank in _get_collector_model_instances(collector, 'taxontreedefitem')
+        if rank.id not in processed_ids
+    ]
+    _reparent_taxon_rank_children(ranks_to_delete)
+
+    if ranks_to_delete:
+        collector._taxon_rank_delete_prepared_ids = processed_ids.union(
+            {rank.id for rank in ranks_to_delete}
+        )
+
+    return None
+
 def custom_save(self, *args, **kwargs):
     try:
         # Custom save logic here, if necessary
@@ -7337,7 +7388,7 @@ class Taxontreedefitem(model_extras.Taxontreedefitem):
     # Relationships: Many-to-One
     createdbyagent = models.ForeignKey('Agent', db_column='CreatedByAgentID', related_name='+', null=True, on_delete=protect_with_blockers)
     modifiedbyagent = models.ForeignKey('Agent', db_column='ModifiedByAgentID', related_name='+', null=True, on_delete=protect_with_blockers)
-    parent = models.ForeignKey('TaxonTreeDefItem', db_column='ParentItemID', related_name='children', null=True, on_delete=models.CASCADE)
+    parent = models.ForeignKey('TaxonTreeDefItem', db_column='ParentItemID', related_name='children', null=True, on_delete=delete_taxon_rank_parent_with_context)
     treedef = models.ForeignKey('TaxonTreeDef', db_column='TaxonTreeDefID', related_name='treedefitems', null=False, on_delete=models.CASCADE)
 
     class Meta: