refactor(db)!: finalize pooled WNDB v2 migration

app/native/wndb/model/junctions.py

@@ -6,6 +6,7 @@ from ..core.database import (
     ChangeSet,
     DatabaseCommand,
     execute_command,
+    execute_locked_command,
     g_add_prefix,
     g_delete_prefix,
     g_update_prefix,
@@ -94,8 +95,12 @@ class Junction(object):
     def as_dict(self) -> dict[str, Any]:
         return { 'type': self.type, 'id': self.id, 'x': self.x, 'y': self.y, 'elevation': self.elevation }
 
-def _set_junction(name: str, cs: ChangeSet) -> DatabaseCommand:
-    raw_new = get_junction(name, cs.operations[0]['id'])
+def _set_junction(
+    name: str,
+    cs: ChangeSet,
+    current: dict[str, Any] | None = None,
+) -> DatabaseCommand:
+    raw_new = current if current is not None else get_junction(name, cs.operations[0]['id'])
 
     new_dict = cs.operations[0]
     schema = get_junction_schema(name)
@@ -113,11 +118,15 @@ def _set_junction(name: str, cs: ChangeSet) -> DatabaseCommand:
 
 
 def set_junction(name: str, cs: ChangeSet) -> ChangeSet:
-    if 'id' not in cs.operations[0]:
+    operation = cs.operations[0]
+    if 'id' not in operation:
         return ChangeSet()
-    if get_junction(name, cs.operations[0]['id']) == {}:
-        return ChangeSet()
-    return execute_command(name, _set_junction(name, cs))
+
+    def build_command() -> DatabaseCommand | None:
+        current = get_junction(name, operation['id'])
+        return None if current == {} else _set_junction(name, cs, current)
+
+    return execute_locked_command(name, build_command)
 
 
 def _add_junction(name: str, cs: ChangeSet) -> DatabaseCommand: