How many projects will switch back and forth between Python 2 and Python 3. I cannot imagine many. People with either stick or move. I would argue making work to cater for a very small number of people is not cost effective.
I would therefore stick with what I think is the status quo. A build is either Python 2 or Python 3 but you cannot actually tell per se, and the highest available version of pickling is used. This seems to be working well: I have moved all my SCons builds to Python 3 and have no intention of going back to Python 2. On Sat, 2017-09-09 at 22:13 -0400, Bill Deegan wrote: > Greetings, > > This is (I hope) the last issue gating 3.0 release. > > *If we set the default pickle version to 2. (Currently set to > HIGHEST_AVAILABLE, which means 4 for py3.5+ and 2 for py2.7)* > > If you run scons with py2.7 and then run again with py3.x, you'll get > the > following: > ... > scons: *** [$DISTDIR/scons-local-3.0.0.alpha.20170821.tar.gz] > UnicodeDecodeError : 'ascii' codec can't decode byte 0x80 in position > 0: > ordinal not in range(128) > > If you run scons with py3 and then rerun with py2.7, you'll get the > following: > * It will rebuild everything you just built with py3 > > *If we set the default pickle version to HIGHEST_AVAILABLE, which > means 4 > for py3.5+ and 2 for py2.7* > > > Here's the options I see to deal with this: > 1. Always append .py3 to PY3 scons runs' sconsign files > 2. Always append .py# to sconsign files based on what version of > python was > used, ignore pre-existing .sconsigns from older versions > 3. Do something complicated: > a. Leave pickle version as HIGHEST_AVAILABLE, detect version of > pickle > by reading first two bytes. If incompatible version detected, change > file > name to .py# and try reading that one. Always write to .sconsign? Or > write > to file read. > b. ? > > Thoughts? > > -Bill > _______________________________________________ > Scons-dev mailing list > [email protected] > https://pairlist2.pair.net/mailman/listinfo/scons-dev -- Russel. ============================================================================= Dr Russel Winder t: +44 20 7585 2200 voip: sip:[email protected] 41 Buckmaster Road m: +44 7770 465 077 xmpp: [email protected] London SW11 1EN, UK w: www.russel.org.uk skype: russel_winder
signature.asc
Description: This is a digitally signed message part
_______________________________________________ Scons-dev mailing list [email protected] https://pairlist2.pair.net/mailman/listinfo/scons-dev
