AssertionError: write() before start_response() on fcgi

[anonymous]

Have error on url roadmap/admin/general/plugin

A problem occurred in a Python script. Here is the sequence of function calls leading up to the error, in the order they occurred.

 venvp27/lib/python2.7/site-packages/trac/web/_fcgi.py in run(self=<trac.web._fcgi.Request object>)
    569         """Runs the handler, flushes the streams, and ends the request."""
    570         try:
=>  571             protocolStatus, appStatus = self.server.handler(self)
    572         except:
    573             traceback.print_exc(file=self.stderr)
protocolStatus undefined, appStatus undefined, self = <trac.web._fcgi.Request object>, self.server = <trac.web._fcgi.WSGIServer object>, self.server.handler = <bound method WSGIServer.handler of <trac.web._fcgi.WSGIServer object>>
 venvp27/lib/python2.7/site-packages/trac/web/_fcgi.py in handler(self=<trac.web._fcgi.WSGIServer object>, req=<trac.web._fcgi.Request object>)
   1267                             write(data)
   1268                     if not headers_sent:
=> 1269                         write('') # in case body was empty
   1270                 finally:
   1271                     if hasattr(result, 'close'):
write = <function write>
 venvp27/lib/python2.7/site-packages/trac/web/_fcgi.py in write(data='')
   1208         def write(data):
   1209             assert type(data) is str, 'write() argument must be string'
=> 1210             assert headers_set, 'write() before start_response()'
   1211 
   1212             if not headers_sent:
headers_set = []
<type 'exceptions.AssertionError'>: write() before start_response()
      args = ('write() before start_response()',)
      message = 'write() before start_response()'

Not sure about component as mod_wsgi due fcgi

[Jun Omae]

Please provide System Information and Installed Plugins from your about page.

Also, I believe you don't use mod_wsgi. trac/web/_fcgi.py is used only from trac/web/fcgi_frontend.py.

[Jun Omae]

PluginIssue (​th:SimpleMultiProjectPlugin). roadmap/admin/general/plugin page is not provide by Trac.

[anonymous]

It's not about SimpleMultiProjectPlugin just situation when installing, eg. for each, restart screen with trac. Looks like case around .dist-info

pip install svn+https://trac-hacks.org/svn/pydocplugin/0.11/
pip install svn+https://trac-hacks.org/svn/fieldgroupsplugin/1.0/
pip install svn+https://trac-hacks.org/svn/finegrainedpageauthzeditorplugin/0.11/
pip install svn+https://trac-hacks.org/svn/htgroupeditorplugin/0.11/
pip install svn+https://trac-hacks.org/svn/usermanagerplugin/0.11
pip install svn+https://trac-hacks.org/svn/tracdownloaderplugin/0.11/

[Jun Omae]

Please provide System Information and Installed Plugins from your about page (see comment:1).

[Jun Omae]

I tried to reproduce the issue with Trac 1.4.3 and plugins in comment:3 on Apache with mod_fcgid, however unable to reproduce it.

I consider that the situation can happen when a plugin raise RequestDone without sending status and headers. I think the following assertion is not needed.

trac/web/_fcgi.py

@@ -1207 +1207 @@
 
         def write(data):
             assert type(data) is str, 'write() argument must be string'
-            assert headers_set, 'write() before start_response()'
 
             if not headers_sent:
                 status, responseHeaders = headers_sent[:] = headers_set