AttributeError: 'Environment' object has no attribute 'get_db_cnx'

[admin]

How to Reproduce

While doing a GET operation on /newticket, Trac issued an internal error.

(please provide additional details here)

Request parameters:

{}

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36

System Information

Trac	1.2dev
Babel	0.9.6
Docutils	0.8.1
Genshi	0.6 (with speedups)
Mercurial	2.0.2
mod_python	3.3.1
MySQL	server: "5.5.46-0ubuntu0.12.04.2", client: "5.5.46", thread-safe: 1
MySQLdb	1.2.3
Pygments	1.4
Python	2.7.3 (default, Jun 22 2015, 19:59:27) [GCC 4.6.3]
setuptools	18.7
jQuery	1.11.3
jQuery UI	1.11.4
jQuery Timepicker	1.5.5

Enabled Plugins

TracAccountManager	0.4.3
TracMercurial	1.0.0.7.dev0
TracSubTicketsPlugin	0.2.0.dev20160127

Interface Customization

shared-htdocs
shared-templates
site-htdocs	logo.png
site-templates

Python Traceback

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.2dev-py2.7.egg/trac/web/main.py", line 594, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.2dev-py2.7.egg/trac/web/main.py", line 261, in dispatch
    self._post_process_request(req, *resp)
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.2dev-py2.7.egg/trac/web/main.py", line 428, in _post_process_request
    resp = f.post_process_request(req, *resp[:-1])
  File "build/bdist.linux-i686/egg/tracsubtickets/web_ui.py", line 73, in post_process_request
    children = self.get_children(ticket.id)
  File "build/bdist.linux-i686/egg/tracsubtickets/web_ui.py", line 104, in get_children
    db = self.env.get_db_cnx()
AttributeError: 'Environment' object has no attribute 'get_db_cnx'

[Ryan J Ollos]

PluginIssue: ​SubticketsPlugin.

[Christian Boos]

i.e. TracSubTicketsPlugin is not compatible with 1.2dev where Environment.get_db_cnx, which was deprecated some time ago already, was removed — see TracDev/ApiChanges/1.1#Environment.get_db_cnxhasbeenremovedget_db_cnxinTrac1.1.2.