OperationalError: attempt to write a readonly database

[klapenhz@…]

How to Reproduce

While doing a POST operation on /admin/general/perm, Trac issued an internal error.

When I do some input(changes) from cmd (trac-admin) then everything is ok. When I do the same operation from admin panel then every operation on database (sqlite) ends with error (readonly database)

Request parameters:

{u'__FORM_TOKEN': u'42f713d83b40d53cc72ca539',
 'cat_id': u'general',
 'panel_id': u'perm',
 'path_info': None,
 u'remove': u'Remove selected items',
 u'sel': u'Y21zXGVtaWw=:VFJBQ19BRE1JTg=='}

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0

System Information

Trac	1.2
Genshi	0.7 (without speedups)
mod_wsgi	4.4.9 (WSGIProcessGroup WSGIApplicationGroup %{GLOBAL})
Pygments	2.2.0
pysqlite	2.6.0
Python	2.7.13 (v2.7.13:a06454b1afa1, Dec 17 2016, 20:53:40) [MSC v.1500 64 bit (AMD64)]
setuptools	34.3.0
SQLite	3.8.11
jQuery	1.11.3
jQuery UI	1.11.4
jQuery Timepicker	1.5.5

Enabled Plugins

Interface Customization

Python Traceback

Traceback (most recent call last):
  File "C:\Python27\lib\site-packages\trac\web\main.py", line 613, in _dispatch_request
    dispatcher.dispatch(req)
  File "C:\Python27\lib\site-packages\trac\web\main.py", line 253, in dispatch
    resp = chosen_handler.process_request(req)
  File "C:\Python27\lib\site-packages\trac\admin\web_ui.py", line 108, in process_request
    provider.render_admin_panel(req, cat_id, panel_id, path_info)
  File "C:\Python27\lib\site-packages\trac\admin\web_ui.py", line 448, in render_admin_panel
    perm.revoke_permission(subject, action)
  File "C:\Python27\lib\site-packages\trac\perm.py", line 356, in revoke_permission
    self.store.revoke_permission(username, action)
  File "C:\Python27\lib\site-packages\trac\perm.py", line 251, in revoke_permission
    (username, action))
  File "C:\Python27\lib\site-packages\trac\db\api.py", line 122, in execute
    return db.execute(query, params)
  File "C:\Python27\lib\site-packages\trac\db\util.py", line 128, in execute
    cursor.execute(query, params if params is not None else [])
  File "C:\Python27\lib\site-packages\trac\db\util.py", line 72, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
  File "C:\Python27\lib\site-packages\trac\db\sqlite_backend.py", line 88, in execute
    result = PyFormatCursor.execute(self, *args)
  File "C:\Python27\lib\site-packages\trac\db\sqlite_backend.py", line 64, in execute
    args or [])
  File "C:\Python27\lib\site-packages\trac\db\sqlite_backend.py", line 55, in _rollback_on_error
    return function(self, *args, **kwargs)
OperationalError: attempt to write a readonly database

[Jun Omae]

InstallationIssue and a duplicate of #9411.