[Scons-dev] scons trunk is broken..

[Gary Oberbrunner]

On Sun, Apr 27, 2014 at 1:16 PM, anatoly techtonik <techtonik at gmail.com>wrote:


> On Sun, Apr 27, 2014 at 8:08 PM, Gary Oberbrunner <garyo at oberbrunner.com>

> wrote:

> > On Sun, Apr 27, 2014 at 12:54 PM, anatoly techtonik <techtonik at gmail.com

> >

> > wrote:

> >>

> >> I expect a big problem to be cross-python SConstructs. Do we have any

> >> instructions how to write these?

> >

> >

> > I'm not all that concerned about this.  Most people will write

> SConscripts

> > for the python version they're using, whether it's 2 or 3.  So those

> people

> > won't care at all.

>

> Most people write just for "scons" to work. Depending on what this `scons`

> uses, it may execute SConscript with Python 2 and Python 3, and if

> SConscript is written for specific Python version, it may fail.

>


Yup.  They'll have to fix their SConscripts for the other python version.
 Not much we can do about that (except as you say, try to give them some
guidance).



>

> > When the 2 users port to 3, they'll have more problems

> > than just their SConscripts to worry about; probably the SConscript

> changes

> > will be small compared to their other changes.

>

> There are many projects that use Python just for SCons build system (or

> derivative of build system based on SCons).

>


If I understand you correctly, that these people only install Python to run
SCons, that'll be OK because they can install whichever version the project
recommends.  It's my guess that most projects will stay with python2 for at
least a couple more years.



> > And of course if people use

> > python3 features in their SConscripts, python2 users won't be able to use

> > them. Sure, there will be some things to keep in mind like unicode string

> > handling and print functions, but I bet a large majority of simple

> > SConscripts will "just work" or at least a simple 2to3 run will get them

> > close.

>

> Did you test that? There is Blender and Wesnoth that can be immediately

> affected and easy to use. Unfortunately, I can't test them right now.

>


No -- I doubt the python3 branch is even close to ready for that yet.
 Though early reports of it working or not would be helpful!


>

> > If we can create instructions like you're talking about, things to do or

> > things to avoid, and put those on the wiki, that would be excellent.

>  We'll

> > probably have to have some experience before we can do that well though.

>

> I just want to make sure that when people hit problems, there is already

> a page to document the problem. It may happen that we will need to

> introduce shebang header and parse it manually before inclusion to warn

> users that the SConstruct was designed with another Python version in

> mind and that they should expect failures.



We might end up having to do something like that; let's see how things play
out. At this point I'm more concerned with getting it to work at all. :-)
 But as for having a page of tips on the wiki, definitely let's do that
before we release it.

-- 
Gary
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