Update to python 3.1, is it safe?

[Kingoftherings]

I just noticed Python 3.1 got added to the Portage tree in ~arch.
Is it safe to update to it? Doesn't Python 3.x break compatibility with 2.x applications?

Basically, what I'm asking is that if I update, will all my python stuff break?

http://packages.gentoo.org/package/dev-lang/python
If it breaks compatibility with older python apps, I would think it'd be masked.

[michel7]

i just tried it out and NOTHING works. python3 seems to break portage so dont try it ...

[Kingoftherings]

i just tried it out and NOTHING works. python3 seems to break portage so dont try it ...

Oh that's right, portage uses python. So you can't even downgrade?

[michel7]

python3 is installed in a new SLOT so there is no need to downgrade. you can switch between python2/python3 with eselect ...

[gami]

Python 3.1 is indeed installed in a new slot (like every previous new python minor version). And it is not made the default python on your machine unless you choose to do so yourself with eselect-python. So simply installing Python 3.1 should be safe. If you make it the active version you may encounter problems. Feel free to report those.

[poly_poly-man]

Python 3.1 is indeed installed in a new slot (like every previous new python minor version). And it is not made the default python on your machine unless you choose to do so yourself with eselect-python. So simply installing Python 3.1 should be safe. If you make it the active version you may encounter problems. Feel free to report those.

doesn't eselect use python?

[LukynZ]

well yes, it is new slot, but depclean unmerge old one and then is a problem 'cause emerge is in python...

[blm]

well yes, it is new slot, but depclean unmerge old one and then is a problem 'cause emerge is in python...

Yes, this is indeed a problem... Not thinking I went ahead and did a depclean and removed python-2.6. I ran eselect to switch to python-3.1 but everything portage related is broken. Anyone have any suggestions on how I can get 3.1 working properly with all the portage utils?

When I run emerge I get the following:

Code: Select all

  File "/usr/bin/emerge", line 41
    except PermissionDenied, e:
                           ^
SyntaxError: invalid syntax

Or if I try to run python-updater, which calls portageq:

Code: Select all

  File "/usr/bin/portageq", line 52
    print "ERROR: insufficient parameters!"
                                          ^
SyntaxError: invalid syntax
* Unable to proceed. Can not find PORTDIR. Make sure the command:
*  
*   portageq portdir
* returns a value. If it doesn't, make sure you have updated to
* latest portage version.
*  
* Report bugs to http://bugs.gentoo.org/

I tried editing emerge and portageq to use /usr/bin/python3.1 instead of the /usr/bin/python wrapper to no avail -- results are the same.

[LukynZ]

I fix it by downloading python 2.5, configure and make it in my directory, made a link to this directory and emerge normally 2.6, then switch it by eselect to 2.6 and everything is fine

[Arfrever]

Python 3.1 is indeed installed in a new slot (like every previous new python minor version). And it is not made the default python on your machine unless you choose to do so yourself with eselect-python. So simply installing Python 3.1 should be safe. If you make it the active version you may encounter problems. Feel free to report those.

doesn't eselect use python?

eselect is written in bash.

[Kingoftherings]

I tried editing emerge and portageq to use /usr/bin/python3.1 instead of the /usr/bin/python wrapper to no avail -- results are the same.

The problem is that Python 3.x changed the 2.x language syntax. So emerge has to be rewritten to support 3.x.
This is the biggest syntax change:

Code: Select all

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

[mtjm]

The problem is that Python 3.x changed the 2.x language syntax. So emerge has to be rewritten to support 3.x.
This is the biggest syntax change:

Code: Select all

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

The following works in Python 2.6:

Code: Select all

from __future__ import print_function
print("The answer is", 2*2)

For every program it is possible to make it work with both Python 2.6 and Python 3.0.

[Bill Cosby]

I recommend Paludis as a Portage replacement, wasn't it target of attacks because of ABI breakages of C++?

[Arfrever]

The problem is that Python 3.x changed the 2.x language syntax. So emerge has to be rewritten to support 3.x.
This is the biggest syntax change:

Code: Select all

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

The following works in Python 2.6:

Code: Select all

from __future__ import print_function
print("The answer is", 2*2)

The following works in both Python 3.* and all versions of Python 2.*:

Code: Select all

print("The answer is %s" % (2*2))

Anyway `2to3 -f print` automatically updates call to print().

[Kingoftherings]

The problem is that Python 3.x changed the 2.x language syntax. So emerge has to be rewritten to support 3.x.
This is the biggest syntax change:

Code: Select all

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

The following works in Python 2.6:

Code: Select all

from __future__ import print_function
print("The answer is", 2*2)

For every program it is possible to make it work with both Python 2.6 and Python 3.0.

Yeah you're right, but the point being that there are changes that don't work in 2.6.

[Naib]

python3 is slotted alongside python2.5 and python2.6
There is already a patchset for portage for it to work with python3

so just don't emerge -C python-2.x just yet (prob won't be feasable till Q2 next year in all honesty and even then some scripts will still rely on a py2.x runtime for a while like plone which only works with py2.4)
if you did you can grab the patchsets from the gentoo python testing overlay and manually add them if you have fubar'ed yr setup

I am guessing this is just to get it into the tree (since it does work well, be it with nothing else since nothing else has been ported ) so that as more and more support libs are converted over moving to py3 will be easy in gentoo

[Naib]

I tried editing emerge and portageq to use /usr/bin/python3.1 instead of the /usr/bin/python wrapper to no avail -- results are the same.

The problem is that Python 3.x changed the 2.x language syntax. So emerge has to be rewritten to support 3.x.
This is the biggest syntax change:

Code: Select all

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

print is the biggest breakage since it is a keyword -> function change but it isn't the worst (that can easily be fixed via a sed)
how strings are formatted is a bigger syntax change in my opinion

tbf py2.x -> py3 isn't as bad as the noise is making out. It isn't the 1st time python have broken backwards compatibility, I was bitten py2.3 -> py2.4 when they removed means to access the list being constructed within the list-comprehension, its just this time round there are some bigger syntax changes

[blm]

Doing a manual build of python 2.6 (making sure to install it in a good place!) from source was the easiest thing for me. I just had to edit /usr/bin/emerge and /usr/bin/ebuild to use this installation so I could properly emerge python 2.6 and get it slotted alongside the new 3.1. Thanks for the advice to those who replied!

[mtjm]

tbf py2.x -> py3 isn't as bad as the noise is making out. It isn't the 1st time python have broken backwards compatibility, I was bitten py2.3 -> py2.4 when they removed means to access the list being constructed within the list-comprehension, its just this time round there are some bigger syntax changes

2.4, 2.5 and 2.6 all required porting of some programs. The Plone CMS still uses Python 2.4. For Python 3 just some more changes are done, some of them are removal of features having better alternatives since 2.4 or earlier.

[ebichu]

I have python 3.1 and 2.6 installed nicely. I take it it isn't safe a good idea to run 'python-updater' yet due to backwards incompatibilities? Anyway, I tried python-updater (version 0.7) in '--pretend' mode and it wanted to "upgrade" from 3.1 to 2.6 (!) but didn't find any packages that needed to be reemerged.

[Naib]

make sure : eselect python list is set to py2.6 (python are going for a python wrapper script for multABI compat mode via EPYTHON variable)

python-updater would only work if you changed the eselect python setting tho

[ebichu]

make sure : eselect python list is set to py2.6 (python are going for a python wrapper script for multABI compat mode via EPYTHON variable)

python-updater would only work if you changed the eselect python setting tho

Thanks, I forgot python-updater updates to the 'currently selected' version, not the 'latest' version. (And don't worry, I won't make 3.1 the current one just yet!)

[carbonat]

Apple Mac OS X was initially supported in the main Gentoo portage tree with the ppc-macos keyword. The approach taken then, however, resulted in too many problems, which was the drive behind creating Prefixed Portage. Bootstrapping on OS X is relatively simple, as the system itself provides most of the jobs get up to speed quickly. Prefixed Portage is tested and supported on Mac OS X Tiger and Leopard on PPC and x86 architectures. Stellenangebote
Tests on PPC Panther were successful, but the platform itself isn't fully supported any more.

[Mike Hunt]

I like this:

Code: Select all

# cd /usr/portage/profiles/package.mask
# grep -B 2 python ./*
./funtoo-cautionary-# Daniel Robbins <drobbins@funtoo.org> (02 Aug 2009)
./funtoo-cautionary-# let's watch upstream bugs for a bit:
./funtoo-cautionary:>=dev-lang/python-3

[pappy_mcfae]

Somehow, I get the feeling there is wisdom in those words...as in I'm staying with 2.6 until forced to change, or until 3.1-r1. Whenever I change to it, I get errors right off the bat, like python-updater, for example. Portage dies, too, of course.

Blessed be!
Pappy