HI All, To add my 2¢ - I would _strongly_ argue that the closer to the core of cctbx the code goes, the longer it should remain compatible with both languages - things at the periphery (i.e. GUI code) may need to transition in a hurry, but libtbx (say) should aim to stay compatible for a very long time. At the same time, the core code should ideally be the _first_ to be ported to both 2 / 3 compatibility so that packages built on top have freedom, but it seems on that one we are kind-of inside out… Best wishes Graeme On 2 Nov 2018, at 04:25, Billy Poon mailto:[email protected]> wrote: Hi David, The plan is to have code that is compatible with both Python 2 and Python 3. In terms of a post-transition period, I don't think we've though about a timeline for when we make the switch to Python 3 only, so it's open for discussion. I'm trying to get things running on Python 3 first! I don't know if a specific month in 2020 has been set yet for the official end of Python 2, so the period of Python 2/3 compatibility can probably go into 2020. And since Python 2.0 source code is still available, I would guess that Python 2.7 source code will be available for a while in case we need it past the official end of Python 2. -- Billy K. Poon Research Scientist, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory 1 Cyclotron Road, M/S 33R0345 Berkeley, CA 94720 Tel: (510) 486-5709 Fax: (510) 486-5909 Web: https://phenix-online.orghttps://phenix-online.org/ On Thu, Nov 1, 2018 at 5:07 AM David Waterman mailto:[email protected]> wrote: Hi folks, It's great to see the momentum building behind the project to migrate to Python 3. From the roadmaphttps://github.com/cctbx/cctbx_project/wiki/Python-3-roadmap, there is clearly still some way to go, but current activity makes me wonder if the proposed deadline of complete migration by 2020 might be beaten easily. What is not clear from the roadmap is whether there are any plans for a post-transition grace period, in which we have switched from writing forwards compatible Python 2 code to writing backwards compatible Python 3 code. Has this been thought about? Or will it be the case that the first commit of Py3-only code seals the deal? I ask because CCP4 has to support a large number of Python projects and these have not all considered the Python 3 switch nearly as seriously as cctbx yet. What I would like to request is a reasonable period of backwards compatibility is ensured to allow other CCP4 projects to catch up, and that this protected period is enshrined within the roadmap or developer guidelines. What do you think? Best wishes -- David _______________________________________________ cctbxbb mailing list [email protected]mailto:[email protected] http://phenix-online.org/mailman/listinfo/cctbxbb _______________________________________________ cctbxbb mailing list [email protected]mailto:[email protected] http://phenix-online.org/mailman/listinfo/cctbxbb -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom