id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc,branch,changelog,apichanges,internalchanges 13496,"Uploading an attachment fails with ""AssertionError: write() before start_response()""",anonymous,,"When adding an attachment to a wiki page (or just clicking the cancel button on the Add Attachment page) I get the error below in the browser (and in the Apache error log). No attachment is saved or added to the wiki page. Trac version: 1.5.4dev from the trunk at revision 17603 OS: Fedora Server 34 Python version: 3.9.4 {{{ Traceback (most recent call last): File ""/usr/local/lib/python3.9/site-packages/trac/web/_fcgi.py"", line 572, in run protocolStatus, appStatus = self.server.handler(self) File ""/usr/local/lib/python3.9/site-packages/trac/web/_fcgi.py"", line 1250, in handler write(b'') # in case body was empty File ""/usr/local/lib/python3.9/site-packages/trac/web/_fcgi.py"", line 1203, in write assert headers_set, 'write() before start_response()' AssertionError: write() before start_response() }}} ",defect,closed,normal,,web frontend,,major,duplicate,,,,,,