Uploading .png attachment causes error

[netdragon@…]

If I upload a .png file in attachment, I get an error. However, .zip files work fine for some reason.

Traceback (most recent call last):

  File "/usr/local/lib/python2.5/site-packages/trac/web/main.py", line 387, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.5/site-packages/trac/web/main.py", line 237, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/local/lib/python2.5/site-packages/trac/attachment.py", line 361, in process_request
    self._do_save(req, attachment)
  File "/usr/local/lib/python2.5/site-packages/trac/attachment.py", line 450, in _do_save
    size = upload.file.len
AttributeError: 'cStringIO.StringO' object has no attribute 'len'

[anonymous]

Traceback (most recent call last):
  File "/usr/local/lib/python2.5/site-packages/trac/web/main.py", line 387, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.5/site-packages/trac/web/main.py", line 237, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/local/lib/python2.5/site-packages/trac/attachment.py", line 361, in process_request
    self._do_save(req, attachment)
  File "/usr/local/lib/python2.5/site-packages/trac/attachment.py", line 450, in _do_save
    size = upload.file.len
AttributeError: 'cStringIO.StringO' object has no attribute 'len'

[netdragon@…]

I just tried to upload a zip here and got an error too

Instructions:

• Take ​http://www.rpi.edu/~boberb/scriptsmall.zip
• Extract .png file
• Try uploading .png file

[Emmanuel Blot]

Probable duplicate of #4311.

Please search the ticket database before creating a new ticket.
Moreover do not forget to define which version of Trac you're using.