[Twisted-Python] Twisted is now under the MIT license.

Mike C. Fletcher mcfletch at rogers.com
Wed Aug 25 22:33:45 MDT 2004

Sergio Trejo wrote:

> I have yet to read the MIT license, 

Take 30 seconds and do so ;) .  I think you'll find it's not the most 
evil thing in the world...


If you are using *any* open source project (and many closed source ones 
too), then you are almost certainly using either MIT or BSD-licensed 
code, and if you are using Twisted, then you are certainly using code 
which has a far more complex and scary licensing history (i.e. Python 
itself) than something which is licensed solely and explicitly under 
MIT.  Basically MIT is one of the least restrictive licenses available, 
far less restrictive than LGPL, for instance.  It says (approximately) 
you can do whatever you like as long as you don't sue the creator, and 
you retain the license + copyright notice in the source.

As for the issue of how contributions work, Twisted has, as far as I 
know up until this date required assignment of copyright (to IIRC 
Glyph).  That allows Glyph to relicense the project anyway he feels at 
some point.  There is some legal murkiness in the US around the question 
of "joint" copyright, with most modern licenses tending to require that 
there be a single owner of the copyright who provides irrevocable 
sub-licenses back to the original author to avoid that murkiness.

There is no legal reason to stop assigning copyright to a single person 
or entity as far as I know, but as long as each contributor is 
contributing their work under MIT license, the results can be combined 
(though technically each licensor would then require that their license 
+ copyright statement be included, which can become rather ugly if there 
are a few hundred individual contributors).  Assignment with irrevocable 
back-licenses seems to be the path most "monied" open source projects 
(i.e. those who can afford intellectual property lawyers) are taking, 
btw.  However, most of these concerns tend to drop out when everything 
being considered is under MIT/BSD-style licenses, if the creator has the 
right to apply any license at all, applying MIT/BSD basically means that 
anyone can use the code for whatever purpose, so it doesn't particularly 
matter (other than for tracking copyright and license attributions) who 
owns the copyright.

As for whether the license would be enforceable solely under U.S. law; 
you are asking the wrong question (do you really care whether it's 
enforceable in Nairobi?), what you want to know is whether it is a valid 
license[1] under the laws of your own country.  The MIT license is an 
extremely simple license statement.  A clear statement that you can use 
the software for basically any purpose is far more likely to be valid in 
multiple countries than the kind of overwrought licenses created by 
practitioners focusing solely on a particular country's legal 
idiosyncrasies.  There may be jurisdictions under which the clauses 
disclaiming liability are not allowed.  Arguably that would either leave 
the contributors open to liability damages, or entirely nullify the 
license.  If you are really worried about that, then you'd have to talk 
to a lawyer (and I'm not one, of course)... and maybe a psychiatrist :) .

With respect,

[1] Keep in mind that a license *loosens* restrictions that would 
otherwise be present.  The enforceable restrictions on a license are 
simply trying to retain some of the already present restrictions and/or 
trade restraint of action in some form for the right to traverse the 
granted monopoly.  In the MIT license case, unless you're planning to 
sue the developers for liability, or for some reason feel the need to 
strip off the copyright statement and claim the product as your own 
creation, there's very little that the copyright holders can enforce 
against you.

  Mike C. Fletcher
  Designer, VR Plumber, Coder

More information about the Twisted-Python mailing list