What is 'tuple' object has no attribute 'is_prerelease' while installing zc.buildout=1.7.1

(plone-python)tclap1006@tclap1006-Lenovo-G50-70:~/Desktop/myplonesite/devtools$ bin/buildout
While:
Installing.
Checking for upgrades.
Getting distribution for 'zc.buildout==1.7.1'.

An internal error occurred due to a bug in either zc.buildout or in a
recipe being used:
Traceback (most recent call last):
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/buildout.py", line 1992, in main
getattr(buildout, command)(args)
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/buildout.py", line 515, in install
self._maybe_upgrade()
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/buildout.py", line 950, in _maybe_upgrade
allow_hosts = self._allow_hosts
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 883, in install
return installer.install(specs, working_set)
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 664, in install
for_buildout_run=for_buildout_run):
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 496, in _get_dist
dist, avail = self._satisfied(requirement)
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 253, in _satisfied
return None, self._obtain(req, source)
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 439, in _obtain
if _final_version(dist.parsed_version)
File "/home/tclap1006/Desktop/myplonesite/devtools/eggs/zc.buildout-2.5.0-py2.7.egg/zc/buildout/easy_install.py", line 1500, in _final_version
return not parsed_version.is_prerelease
AttributeError: 'tuple' object has no attribute 'is_prerelease'

you are using zc.buildout==2.5 and you require zc.buildout==1.7.1.

you probably bootstrapped your installation with an old version of the bootstrap.py script; update the script using something like:

wget http://downloads.buildout.org/2/bootstrap.py -O bootstrap.py

and/or use:

python bootstrap.py --buildout-version=1.7.1

using Python from your virtualenv.

run buildout again.

just a little bit more information on this error as I just stumbled upon it: seems that the cause is a bug in Python 2.7.3.

in my specific case I have one machine with Debian Wheezy:

# apt-cache policy python
python:
  Installed: 2.7.3-4+deb7u1
  Candidate: 2.7.3-4+deb7u1
  Version table:
 *** 2.7.3-4+deb7u1 0
        500 http://mirrors.digitalocean.com/debian/ wheezy/main amd64 Packages
        100 /var/lib/dpkg/status

in this machine I can't upgrade Python easily and I must use zc.buildout 1.7.1.