Re: "pip install scons" result in a broken installation that is unusable

Dear Bill,

Thank you for your reply.

For me it still fails:

[sfux@lo-login-01 ~]$ pip install --index-url https://test.pypi.org/simple/ scons==3.1.0.alpha.20181011
Looking in indexes: https://test.pypi.org/simple/
Collecting scons==3.1.0.alpha.20181011
Installing collected packages: scons
Successfully installed scons-3.1.0a20181011
[sfux@lo-login-01 ~]$ scons
SCons import failed. Unable to find engine files in:
  /cluster/apps/python/2.7.14/bin/../engine
  /cluster/apps/python/2.7.14/bin/scons-local-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/bin/scons-local
  /cluster/apps/python/2.7.14/lib64/python2.7/site-packages/lib/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib64/python2.7/site-packages/lib/python2.7/site-packages/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib/python2.7/site-packages/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib/python2.7/site-packages/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib64/scons-3.1.0.alpha.20181011
  /cluster/apps/python/2.7.14/lib64/python2.7/site-packages/lib/scons
  /cluster/apps/python/2.7.14/lib/scons
  /cluster/apps/python/2.7.14/lib/scons
  /cluster/apps/python/2.7.14/lib64/python2.7/site-packages/lib/python2.7/site-packages/scons
  /cluster/apps/python/2.7.14/lib/python2.7/site-packages/scons
  /cluster/apps/python/2.7.14/lib/python2.7/site-packages/scons
  /cluster/apps/python/2.7.14/lib64/scons
Traceback (most recent call last):
  File "/cluster/apps/python/2.7.14/bin/scons", line 192, in <module>
    import SCons.Script
ImportError: No module named SCons.Script
[sfux@lo-login-01 ~]$

Not using virtualenv is a personal preference, like not using Anaconda to install Python itself or like preferring pip over distutils. I don't like the additional step of activating the virtualenv because I would like to keep things as simple as possible for our cluster users.

If virtualenv is a hard requirement for using SCons, then this should be added to the Readme.md file on github. Currently the Readme.md file states with regards to dependencies:
Execution Requirements

Running SCons requires Python version 2.7.* and Python 3.5 or higher. There should be no other dependencies or requirements to run SCons.

Installation Requirements

Nothing special.

Best regards

Sam

--
ETH Zurich, Dr. sc. ETH Samuel Fux
High Performance Computing, Scientific IT Services
WEC D 13, Weinbergstrasse 11, 8092 Zurich, Switzerland
Phone +41 44 632 57 63, http://www.id.ethz.ch/
[email protected]
________________________________
Von: Scons-users [[email protected]]" im Auftrag von "Bill Deegan [[email protected]]
Gesendet: Donnerstag, 11. Oktober 2018 19:45
An: SCons users mailing list
Betreff: Re: [Scons-users] "pip install scons" result in a broken installation that is unusable

This issue is resolved by patch merged into master in may.
https://github.com/SCons/scons/pull/3134

You can try via package I just uploaded to testpypi
pip install --index-url https://test.pypi.org/simple/ scons==3.1.0.alpha.20181011

Please let me know if this works for you.
I tried in a freshly built python on my linux system.
Seems to work for me.

-Bill



On Thu, Oct 11, 2018 at 1:37 PM Mats Wichmann <[email protected]<mailto:[email protected]>> wrote:
On 10/11/2018 10:37 AM, Mats Wichmann wrote:
> On 10/11/2018 10:19 AM, Bill Deegan wrote:
>> It should work with recent pip.
>> Let me take a look today.
>> -Bill
>
> IMO, some of the paths are ready as they are and should not be joined
> with further bits. a little reorg is needed there.

to be a little less cryptic, it seems that the very first place a path
could be added to prefs is here:

# - running from egg check
try:
    import pkg_resources
except ImportError:
    pass
else:
    # when running from an egg add the egg's directory
    try:
        d = pkg_resources.get_distribution('scons')
    except pkg_resources.DistributionNotFound:
        pass
    else:
        prefs.append(d.location)

This stanza succeeds on all kinds of installations, "running from egg"
does not seem precise; whatever get_distribution looks for is found both
in Linux distro packages and pip installed locations.  This gives you
back a path that does not want 'lib' or 'lib/pythonX.Y/site-packages'
appended. For example for a particular virtualenv that has pip-install'd
scons, that stanza yields:

/home/mats/.virtualenvs/py27+scons/lib/python2.7

Further down, after the appending that happens in the two list
comprehensions to all the paths in prefs, that expanded to these two:

/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib
/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib/python2.7/site-packages

which are throwaways, engine will never be found in those after they are
expanded to these four locations on the final round:

/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib/scons-3.0.1
/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib/python2.7/site-packages/scons-3.0.1
/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib/scons
/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/lib/python2.7/site-packages/scons

there is no site-packages/lib and definitely no
site-packages/lib/.../site-packages - really this is the problem Samuel
is seeing.

What we really wanted to generate from that original first path was:

/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/scons-3.0.1
/home/mats/.virtualenvs/py27+scons/lib/python2.7/site-packages/scons

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