[Python-Dev] Licensing issue (?) for Frozen Python? [was: More optimisation ideas] (original) (raw)

Stephen J. Turnbull stephen at xemacs.org
Fri Feb 5 23:31:15 EST 2016

Executive summary:

There is no licensing issue because Python isn't copyleft. Stick to the pragmatic technical issue of how to reliably provide corresponding source to those who want to look at that source (just because that's how we do things in Python).

Emile van Sebille writes:

Except for that nasty licensing issue requiring source code.

CPython is not now and never has been copyleft. CPython is distributed by the PSF as open source with a license that permits redistribution of original source and derivatives (including executables), but legally need not remain open source downstream.

The remaining issue is the PSF's CLA which permits the PSF to relicense/sublicense under any open source license. However it's not clear to me that the PSF is required by the CLA to distribute source! It receives the code under very permissive licenses, and the CLA merely names the contributor's chosen license. I imagine those licenses determine whether the PSF must distribute source. If so, no, not even the PSF is bound (legally) to distribute Python source.

Of course if you want to you can GPL Python (I think that's now possible, at one time there was a issue with the CNRI license IIRC), and then licensees of your distribution (but not you!) are required to distribute source.

Of course our trust in the PSF is based on the moral principle of reciprocity: we contribute to the PSF's distribution as open source (according to the CLA) in large part because we expect to receive open source back. But if the PSF ever goes so wrong as to even think of taking advantage of that loophole, we are well and truly hosed anyway. (Among other things, that means a voting majority of the current PSF Board -- many of them core developers -- fell under a bus.) So don't worry about it.

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