IntegrityError when fs-type plugin instance finishes where feed is shared with another user

[jennydaman]

1. Set up CUBE with two users, e.g. bobb and alice.
2. As user bobb, create a fs-type plugin instance which runs for at least 60 seconds, e.g. pl-simplefsapp ... --sleepLength 60
3. Share the feed with (i.e. create a Userpermission for the feed for) user alice.
4. When the plugin instance finishes, the worker spits out this error:

[2025-01-17 00:13:19,422] [INFO][plugininstances.services.manager][manager.py:667 save_plugin_instance_final_status] Setting output folder's permissions for job chris-jid-3 ...
[2025-01-17 00:13:19,430] [ERROR][trace 9 136815613015872] Task plugininstances.tasks.check_plugin_instance_exec_status[0de5b5c7-937f-4535-915a-2d3ea57eaed1] raised unexpected: IntegrityError('duplicate key value violates unique constraint "core_folderuserpermission_folder_id_user_id_8870905f_uniq"\nDETAIL:  Key (folder_id, user_id)=(23, 2) already exists.')
Traceback (most recent call last):
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
psycopg.errors.UniqueViolation: duplicate key value violates unique constraint "core_folderuserpermission_folder_id_user_id_8870905f_uniq"
DETAIL:  Key (folder_id, user_id)=(23, 2) already exists.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/opt/app-root/lib64/python3.11/site-packages/celery/app/trace.py", line 477, in trace_task
    R = retval = fun(*args, **kwargs)
                 ^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/celery/app/trace.py", line 760, in __protected_call__
    return self.run(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/src/plugininstances/tasks.py", line 59, in check_plugin_instance_exec_status
    plg_inst_manager.check_plugin_instance_app_exec_status()
  File "/opt/app-root/src/plugininstances/services/manager.py", line 315, in check_plugin_instance_app_exec_status
    self._handle_finished_successfully_status()
  File "/opt/app-root/src/plugininstances/services/manager.py", line 938, in _handle_finished_successfully_status
    self.save_plugin_instance_final_status()
  File "/opt/app-root/src/plugininstances/services/manager.py", line 673, in save_plugin_instance_final_status
    self.c_plugin_inst.output_folder.parent.grant_user_permission(user, 'w')
  File "/opt/app-root/src/core/models.py", line 213, in grant_user_permission
    FolderUserPermission.objects.create(folder=self, user=user, permission=permission)
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/manager.py", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/query.py", line 658, in create
    obj.save(force_insert=True, using=self.db)
  File "/opt/app-root/src/core/models.py", line 447, in save
    super(FolderUserPermission, self).save(*args, **kwargs)
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/base.py", line 814, in save
    self.save_base(
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/base.py", line 877, in save_base
    updated = self._save_table(
              ^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/base.py", line 1020, in _save_table
    results = self._do_insert(
              ^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/base.py", line 1061, in _do_insert
    return manager._insert(
           ^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/manager.py", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/query.py", line 1805, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/models/sql/compiler.py", line 1822, in execute_sql
    cursor.execute(sql, params)
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 102, in execute
    return super().execute(sql, params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 67, in execute
    return self._execute_with_wrappers(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 84, in _execute
    with self.db.wrap_database_errors:
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/opt/app-root/lib64/python3.11/site-packages/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/app-root/lib64/python3.11/site-packages/psycopg/cursor.py", line 97, in execute
    raise ex.with_traceback(None)
django.db.utils.IntegrityError: duplicate key value violates unique constraint "core_folderuserpermission_folder_id_user_id_8870905f_uniq"
DETAIL:  Key (folder_id, user_id)=(23, 2) already exists.