Fix: Swapped IDs in parent_tags DB table

src/tagstudio/core/enums.py

@@ -84,4 +84,4 @@ class LibraryPrefs(DefaultEnum):
 
     IS_EXCLUDE_LIST = True
     EXTENSION_LIST = [".json", ".xmp", ".aae"]
-    DB_VERSION = 9
+    DB_VERSION = 10

src/tagstudio/core/library/alchemy/library.py

@@ -272,8 +272,8 @@ def migrate_json_to_sqlite(self, json_lib: JsonLibrary):
 
         # Parent Tags (Previously known as "Subtags" in JSON)
         for tag in json_lib.tags:
-            for child_id in tag.subtag_ids:
-                self.add_parent_tag(parent_id=tag.id, child_id=child_id)
+            for parent_id in tag.subtag_ids:
+                self.add_parent_tag(parent_id=parent_id, child_id=tag.id)
 
         # Entries
         self.add_entries(
@@ -491,6 +491,8 @@ def open_sqlite_library(self, library_dir: Path, is_new: bool) -> LibraryStatus:
                     self.apply_db8_default_data(session)
                 if db_version < 9:
                     self.apply_db9_filename_population(session)
+                if db_version < 10:
+                    self.apply_db10_parent_repairs(session)
 
             # Update DB_VERSION
             if LibraryPrefs.DB_VERSION.default > db_version:
@@ -616,6 +618,20 @@ def apply_db9_filename_population(self, session: Session):
         session.commit()
         logger.info("[Library][Migration] Populated filename column in entries table")
 
+    def apply_db10_parent_repairs(self, session: Session):
+        """Apply database repairs introduced in DB_VERSION 10."""
+        logger.info("[Library][Migration] Applying patches to DB_VERSION: 10 library...")
+        with session:
+            # Repair parent-child tag relationships that are the wrong way around.
+            stmt = update(TagParent).values(
+                parent_id=TagParent.child_id,
+                child_id=TagParent.parent_id,
+            )
+            session.execute(stmt)
+            session.flush()
+
+            session.commit()
+
     @property
     def default_fields(self) -> list[BaseField]:
         with Session(self.engine) as session:
@@ -1588,22 +1604,22 @@ def update_parent_tags(self, tag: Tag, parent_ids: list[int] | set[int], session
 
         # load all tag's parent tags to know which to remove
         prev_parent_tags = session.scalars(
-            select(TagParent).where(TagParent.parent_id == tag.id)
+            select(TagParent).where(TagParent.child_id == tag.id)
         ).all()
 
         for parent_tag in prev_parent_tags:
-            if parent_tag.child_id not in parent_ids:
+            if parent_tag.parent_id not in parent_ids:
                 session.delete(parent_tag)
             else:
                 # no change, remove from list
-                parent_ids.remove(parent_tag.child_id)
+                parent_ids.remove(parent_tag.parent_id)
 
                 # create remaining items
         for parent_id in parent_ids:
             # add new parent tag
             parent_tag = TagParent(
-                parent_id=tag.id,
-                child_id=parent_id,
+                parent_id=parent_id,
+                child_id=tag.id,
             )
             session.add(parent_tag)
 

src/tagstudio/core/library/alchemy/models.py

@@ -99,8 +99,8 @@ class Tag(Base):
     aliases: Mapped[set[TagAlias]] = relationship(back_populates="tag")
     parent_tags: Mapped[set["Tag"]] = relationship(
         secondary=TagParent.__tablename__,
-        primaryjoin="Tag.id == TagParent.parent_id",
-        secondaryjoin="Tag.id == TagParent.child_id",
+        primaryjoin="Tag.id == TagParent.child_id",
+        secondaryjoin="Tag.id == TagParent.parent_id",
         back_populates="parent_tags",
     )
     disambiguation_id: Mapped[int | None]

src/tagstudio/core/library/alchemy/visitors.py

@@ -31,17 +31,15 @@
 
 logger = structlog.get_logger(__name__)
 
-# TODO: Reevaluate after subtags -> parent tags name change
 TAG_CHILDREN_ID_QUERY = text("""
--- Note for this entire query that tag_parents.child_id is the parent id and tag_parents.parent_id is the child id due to bad naming
 WITH RECURSIVE ChildTags AS (
-    SELECT :tag_id AS child_id
+    SELECT :tag_id AS tag_id
     UNION
-    SELECT tp.parent_id AS child_id
-	FROM tag_parents tp
-    INNER JOIN ChildTags c ON tp.child_id = c.child_id
+    SELECT tp.child_id AS tag_id
+    FROM tag_parents tp
+    INNER JOIN ChildTags c ON tp.parent_id = c.tag_id
 )
-SELECT child_id FROM ChildTags;
+SELECT tag_id FROM ChildTags;
 """)  # noqa: E501
 
 

src/tagstudio/qt/widgets/migration_modal.py

@@ -641,7 +641,7 @@ def check_subtag_parity(self) -> bool:
             for tag in self.sql_lib.tags:
                 tag_id = tag.id  # Tag IDs start at 0
                 sql_parent_tags = set(
-                    session.scalars(select(TagParent.child_id).where(TagParent.parent_id == tag.id))
+                    session.scalars(select(TagParent.parent_id).where(TagParent.child_id == tag.id))
                 )
 
                 # JSON tags allowed self-parenting; SQL tags no longer allow this.

tests/qt/test_build_tag_panel.py

@@ -79,7 +79,7 @@ def test_build_tag_panel_set_parent_tags(library, generate_tag):
     assert parent
     assert child
 
-    library.add_parent_tag(child.id, parent.id)
+    library.add_parent_tag(parent.id, child.id)
 
     child = library.get_tag(child.id)