[PyQt] A nasty licencing question

V. Armando Sole sole at esrf.fr
Mon Jul 30 18:07:39 BST 2018

On 30.07.2018 10:14, Sampsa Riikonen wrote:
> On 30.07.2018 00:24, V. Armando Sole wrote:
>> On 29.07.2018 22:23, Sampsa Riikonen wrote:
>>> Is this logic flawed?  Can the snippets be MIT licensed at all.. or 
>>> must
>>> they follow the PyQt licensing scheme, i.e. either GPL or commercial.
>>> In the latter case, can the snippets be MIT licensed?
>> Why not? For instance, your code might end up (with or without
>> modifications) being used with PySide.
> But once you distribute (i.e. make public) a code that has the magic
> lines "from PyQt5 import .." (and if you don't have the commercial PyQt
> license) *bang* it will be GPL forever.  :)

Certainly not. If the original code is made public under MIT, it will be 
possible to modify it according to the MIT license.

If the person modifying/using the code decides to license the derived 
code according to a more restrictive license, it is also possible. You 
can put "from PyQt5 import .." and still license your code under MIT, 
under GPL, under LGPL or whatever you want:

A) If the end user of your library has a commercial PyQt license (s)he 
will not be forced to open the derived code (unless you have chosen GPL 
or LGPL as license of YOUR code).

B) (s)he will be able to change "from PyQt5" by "from PySide2" and use 
PySide2 without having to be GPL and thus being able to choose MIT, 
LGPL, GPL, Comercial, ...


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