[Python-Dev] (Licensing question) backport of shutil.copyfile() functionality

[Terry Reedy]

On 3/11/2019 10:54 PM, Inada Naoki wrote:

>> Hello,
>> some time ago I contributed a couple of patches to speedup shutil.copy*() functions:
>> https://bugs.python.org/issue33671
>> https://bugs.python.org/issue33695

You retain copyright on the code you contributed.

>> I would like to backport both functionalities so that they can be used on Python 2.7 and <3.8 and put it on PYPI. In order to do so I will basically have to copy some parts of shutil module (copytree() function + the unit-tests I added in BPO-33671 and a couple of other things). Are there constraints regarding this in terms of license? Am I supposed to use GPL? (I was thinking about using MIT)
>>
> 
> First of all, I'm sorry if I'm wrong.  I'm not lawyer.
> 
> You can use both of GPL and MIT.  Users can use your package under it.
> 
> On the other hand, when you publish your package, *you* should follow
> PSF license.
> Read this.  https://docs.python.org/3/license.html
> 
> """
> 3. In the event Licensee prepares a derivative work that is based on or
>     incorporates Python 3.7.2 or any part thereof, and wants to make the
>     derivative work available to others as provided herein, then Licensee hereby
>     agrees to include in any such work a brief summary of the changes
> made to Python
>     3.7.2.
> """
> 
> As you can see, PSF license doesn't force you to use PSF license. (not
> "copyleft")

In fact, the PSF lawyer says one should not use the 'PSF license' as it 
is specilized for the PSF and Python.

> All you need is "brief summary of the changes made to Python".
> 
> I think it can be:
> 
> # Copyright 2001- Python Software Foundation.
> # Copyright 2019- Your Name
> #
> # Following code is from Python standard library (Lib/shutil.py)
> #
> # Changelog:
> #   * ...


-- 
Terry Jan Reedy