[Twisted-Python] What does the LGPL mean in terms of python?

Glyph Lefkowitz glyph at divmod.com
Fri May 28 14:48:08 EDT 2004

On Fri, 2004-05-28 at 13:17, Chris Green wrote:

> For example, is a subclass a derivative work? By the LGPL, it seems to
> be since it's combined completely with the code that is under the
> LGPL. 


Thanks for your questions.  Your concerns are well-founded.  However,
they are thankfully soon to be irrelevant.

Googling the twisted-python archives will give you some background on
the intention and implications of the LGPL as it applies to Twisted. 
However, the LGPL was originally selected as Twisted was largely code
that I wrote personally and many of the interested parties were large
corporations with no experience, knowledge, or interest in open source. 
I wanted a license which was not terribly restrictive but still required
those companies to do investigation into the license, requiring in so
doing that they become at least marginally involved in the community
process.  In that, the confusing wording of the LGPL as it regards
Python code was an asset.  It would be a halfway accurate statement that
I selected the LGPL exactly because it doesn't make any sense.

Now we live in a different world than what Twisted was born into.  First
of all, middleware vendors know what Twisted is and who I am, which is a
bit of a shift :-).  More importantly, IBM, a massive bastion of
technological conservatism, has embraced open source.  By doing this,
they have sent a message to corporate lawyers everywhere that they need
to be aware of the free/open source software phenomenon and be able to
react appropriately to different licenses.  More and more companies are
aware of the need to interact with the community regardless of whether
it's necessary.

Finally, Twisted is no longer a personal effort of my own.  It is truly
a community project; in fact, I think I am falling far behind exarkun in
terms of number of lines committed :).  The community is large enough to
self-sustain without forcing new users to step forward because of an
inconvenient license.

For these reasons, and also to facilitate contribution by those who have
the right to release their own work as open source but NOT to consign
copyright to it (such as students at and employees of MIT), we are going
to be switching to an MIT-style (no pun intended) license soon.  The
real work is going to be filing the verbose license statement off every
source file in the tree and replacing it with a new one.

This has been a long time in coming - the decision was finally made at
PyCon this year and I'm sorry the change hasn't been implemented yet. 
On that note, I think we should change the license text at the top of
each file to simply refer to the TWISTED-LICENSE file in the
distribution or something like that, rather than including disclaimers

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