server/tags: fix removing tags related to others

server/szurubooru/api/tag_api.py

@@ -69,7 +69,7 @@ class TagDetailApi(BaseApi):
                 'Please untag relevant posts first.')
         auth.verify_privilege(ctx.user, 'tags:delete')
         snapshots.save_entity_deletion(tag, ctx.user)
-        ctx.session.delete(tag)
+        tags.delete(tag)
         ctx.session.commit()
         tags.export_to_json()
         return {}

server/szurubooru/func/tags.py

@@ -148,12 +148,21 @@ def get_tag_siblings(tag):
         .limit(50)
     return result
 
+def delete(source_tag):
+    db.session.execute(
+        sqlalchemy.sql.expression.delete(db.TagSuggestion) \
+            .where(db.TagSuggestion.child_id == source_tag.tag_id))
+    db.session.execute(
+        sqlalchemy.sql.expression.delete(db.TagImplication) \
+            .where(db.TagImplication.child_id == source_tag.tag_id))
+    db.session.delete(source_tag)
+
 def merge_tags(source_tag, target_tag):
     db.session.execute(
         sqlalchemy.sql.expression.update(db.PostTag) \
             .where(db.PostTag.tag_id == source_tag.tag_id) \
             .values(tag_id=target_tag.tag_id))
-    db.session.delete(source_tag)
+    delete(source_tag)
 
 def create_tag(names, category_name, suggestions, implications):
     tag = db.Tag()

server/szurubooru/tests/api/test_tag_merging.py

@@ -72,6 +72,30 @@ def test_merging_with_usages(test_ctx, fake_datetime, post_factory):
     assert tags.try_get_tag_by_name('source') is None
     assert tags.get_tag_by_name('target').post_count == 1
 
+def test_merging_when_related(test_ctx, fake_datetime):
+    source_tag = test_ctx.tag_factory(names=['source'], category_name='meta')
+    target_tag = test_ctx.tag_factory(names=['target'], category_name='meta')
+    db.session.add_all([source_tag, target_tag])
+    db.session.flush()
+    referring_tag = test_ctx.tag_factory(names=['parent'])
+    referring_tag.suggestions = [source_tag]
+    referring_tag.implications = [source_tag]
+    db.session.add(referring_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('parent').implications != []
+    assert tags.try_get_tag_by_name('parent').suggestions != []
+    with fake_datetime('1997-12-01'):
+        result = test_ctx.api.post(
+            test_ctx.context_factory(
+                input={
+                    'remove': 'source',
+                    'mergeTo': 'target',
+                },
+                user=test_ctx.user_factory(rank=db.User.RANK_REGULAR)))
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.try_get_tag_by_name('parent').implications == []
+    assert tags.try_get_tag_by_name('parent').suggestions == []
+
 @pytest.mark.parametrize('input,expected_exception', [
     ({'remove': None}, tags.TagNotFoundError),
     ({'remove': ''}, tags.TagNotFoundError),