TicketTagProvider fetching `tags` records before the `tags` table created

[Jun Omae]

This behavior leads ​trac:#13804.

17:43:29 Trac[env] ERROR: Component <Component tracspamfilter.filters.trapfield.TrapFieldFilterStrategy> failed with
Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/trac/env.py", line 382, in component_guard
    yield
  File "/usr/local/lib/python3.13/site-packages/trac/env.py", line 750, in needs_upgrade
    if participant.environment_needs_upgrade():
       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tracspamfilter/filters/trapfield.py", line 116, in environment_needs_upgrade
    chrome.load_template(os.devnull)  # to set chrome.jenv property
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/web/chrome.py", line 1316, in load_template
    jinja2_dirs = self.get_all_templates_dirs()
  File "/usr/local/lib/python3.13/site-packages/trac/web/chrome.py", line 772, in get_all_templates_dirs
    for provider in self.template_providers:
                    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 96, in extensions
    components = [component.compmgr[cls] for cls in classes]
                  ~~~~~~~~~~~~~~~~~^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 238, in __getitem__
    component = cls(self)
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 158, in __call__
    self.__init__()
    ~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tractags/wiki.py", line 101, in __init__
    self.tag_system = TagSystem(self.env)
                      ~~~~~~~~~^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 158, in __call__
    self.__init__()
    ~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tractags/api.py", line 249, in __init__
    self._populate_provider_map()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tractags/api.py", line 465, in _populate_provider_map
    for provider in self.tag_providers)
                    ^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 96, in extensions
    components = [component.compmgr[cls] for cls in classes]
                  ~~~~~~~~~~~~~~~~~^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 238, in __getitem__
    component = cls(self)
  File "/usr/local/lib/python3.13/site-packages/trac/core.py", line 158, in __call__
    self.__init__()
    ~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tractags/ticket.py", line 53, in __init__
    self._fetch_tkt_tags()
    ~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/local/lib/python3.13/site-packages/tractags/ticket.py", line 215, in _fetch_tkt_tags
    rw_cursor.execute("""
    ~~~~~~~~~~~~~~~~~^^^^
        DELETE FROM tags
        ^^^^^^^^^^^^^^^^
    ...<3 lines>...
        """ % (db.cast('tags.name', 'int'), ignore),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        (self.realm,))
        ^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/trac/db/util.py", line 73, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
psycopg2.errors.UndefinedTable: relation "tags" does not exist
LINE 2:                 DELETE FROM tags
                                    ^
UndefinedTable: relation "tags" does not exist
LINE 2:                 DELETE FROM tags
                                    ^

Error: Unable to check for upgrade of tracspamfilter.filters.trapfield.TrapFieldFilterStrategy: UndefinedTable: relation "tags" does not exist
LINE 2:                 DELETE FROM tags
                                    ^

[Jun Omae]

In 18665:

TracTags: use @lazy decorator to avoid fetching records on component initiation as a workaround (refs #14360)

[Jun Omae]

Currently, the tags table is refreshed on each TicketTagProvider initiation. It leads performance issues by many tickets and/or concurrent requests. I think we should provide tags sync command to refresh tags table instead of refreshing on requests.