[Twisted-Python] Twisted & Qt

glyph at divmod.com glyph at divmod.com
Tue Sep 26 14:14:24 EDT 2006

On Tue, 26 Sep 2006 13:01:50 -0400, James Y Knight <foom at fuhm.net> wrote:

>On Sep 26, 2006, at 12:12 PM, glyph at divmod.com wrote:
>>On Tue, 26 Sep 2006 11:42:18 -0400, James Y Knight <foom at fuhm.net>  wrote:
>>>On Sep 26, 2006, at 9:45 AM, glyph at divmod.com wrote:

>>And that's your professional legal opinion?

>We distribute MIT licensed source code.

That is the question, isn't it :).

>>So if you want to write a non-copylefted application, release it under
>>the X11 license, and link it with a GPL-covered library, that is
>>allowed. The linked executable would be covered by the GPL, of
>>course, but the app source code would be covered by the X11 license

The GPL license text doesn't refer to "linking", there's really practically no such thing as "linking" in Python, so this is RMS's opinion of how the license should work in a different context than the one we're talking about.  What's interesting is to what extent the copyright holders in this situation agree, and when (and where) they think this "linking" happens.

>And let's take the example of Python itself, which has a readline  module, 
>distributed under the python license. Again, similar  circumstance. If you 
>actually make use of the readline module, your  program will need to be 
>distributed under the GPL. But the source  code is still Python licensed.

Python is a C program, where the conventional understanding of "linking" makes sense, and readline is copyrighted by the FSF, which makes RMS's interpretation relevant.  This is not the same situation.

>>It may be that riverbank and trolltech agree with this  interpretation. 
>>The response I received wasn't entirely clear.

>If you think that twisted is in imminent danger of a lawsuit from  Riverbank 
>or Trolltech, then by all means simply remove qtreactor  completely.

Obviously not.  The question here is one of intent, not punitive damages.

In Riverbank/Trolltech's case, the license is used as a means to deter commercial users from using the software unless they pay a licensing fee.  Lawsuits, and the threat thereof, are the weapon used to enforce that intent.

I don't think that we should wait until they actually start threatening us with legal action before we do something to put the situation with respect to their code more in line with their intent with their licenses.

>Please don't use the phrase "intellectual property".

I wish I didn't even *know* the phrase, but I was quoting Phil Thompson (Riverbank) directly.  He wrote:

Trolltech will have the same view. As far as they are concerned their
intellectual property is the API and it doesn't matter how it is

This is probably, as you say, legal nonsense.  I don't think Mr. Thompson is a lawyer either, nor is he speaking authoritatively for trolltech's lawyers.  But, he is a copyright holder in this case, and therefore entitled to certain outlandish opinions.

>If it is truly their 
>position that the  textual source code of qtreactor is a derivative work of 
>PyQT, I  think they are quite confused.

If it is your opinion that the "textual source code" is not a derivative work because it merely refers to, but does not incorporate, the text of qtreactor or qt, then the GPL is completely meaningless in the context of Python and there was no point in licensing it that way in the first place.  Python bytecode does not make any additional references to the code it is importing beyond what Python source code does.

In that case the GPL can not apply to Python in any practical way.  I suspect that someone applying the GPL license to a bunch of Python code *would* disagree with that interpratation.

>If it's good enough for KDE, I don't see how it's not good enough for  us. 
>I'm sure many more people with actual legal experience have  looked over the 
>situation with KDE.

Oh yeah, and KDE has never had any problems with licensing ;-).

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