python-build-system does not wrap script correctly

[Foo Chuan Wei <chuanwei.foo@hotmail.com>]

I am trying to package "Speedometer" [1]. This is the package
definition:

--8<---------------cut here---------------start------------->8---
(define-public speedometer
  (package
    (name "speedometer")
    (version "2.8")
    (source
     (origin
       (method url-fetch)
       (uri (pypi-uri "Speedometer" version))
       (sha256
        (base32 "0qgpjmahy0wlfszqxg0067ck2xab5k6j42d0ifxg1j281yqnm9bx"))))
    (build-system python-build-system)
    (arguments
     `(#:python ,python-2))
    (propagated-inputs
     `(("python2-urwid" ,python2-urwid)))
    (home-page "https://excess.org/speedometer/")
    (synopsis "Measure and display the rate of data across a network connection")
    (description
     "Console monitor of the rate of data across a network connection or data
being stored in a file.")
    (license license:lgpl2.1+)))
--8<---------------cut here---------------end--------------->8---

It builds and installs successfully. However, when the wrapper script is
run, this error appears:

--8<---------------cut here---------------start------------->8---
Traceback (most recent call last):
  File "/gnu/store/chr1cx6ia0is8s9d07s1nzdla30r6vs1-speedometer-2.8/bin/.speedometer-real", line 11, in <module>
    load_entry_point('Speedometer==2.8', 'console_scripts', 'speedometer')()
  File "/gnu/store/d3jwdk2v7xck82z3y3hs99033m9nkkw0-python2-2.7.17/lib/python2.7/site-packages/pkg_resources/__init__.py", line 489, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/gnu/store/d3jwdk2v7xck82z3y3hs99033m9nkkw0-python2-2.7.17/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2852, in load_entry_point
    return ep.load()
  File "/gnu/store/d3jwdk2v7xck82z3y3hs99033m9nkkw0-python2-2.7.17/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2443, in load
    return self.resolve()
  File "/gnu/store/d3jwdk2v7xck82z3y3hs99033m9nkkw0-python2-2.7.17/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2449, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/gnu/store/chr1cx6ia0is8s9d07s1nzdla30r6vs1-speedometer-2.8/bin/speedometer.py", line 2
    export PYTHONPATH="/gnu/store/chr1cx6ia0is8s9d07s1nzdla30r6vs1-speedometer-2.8/lib/python2.7/site-packages:/gnu/store/d3jwdk2v7xck82z3y3hs99033m9nkkw0-python2-2.7.17/lib/python2.7/site-packages:/gnu/store/1iszjcyvb537m6cif7fqrrh95r0sg9wp-python2-urwid-2.1.0/lib/python2.7/site-packages${PYTHONPATH:+:}$PYTHONPATH"
                    ^
SyntaxError: invalid syntax
--8<---------------cut here---------------end--------------->8---

There is apparently something wrong with the wrapper script. What is it?

I worked around the problem by adding this phase:

--8<---------------cut here---------------start------------->8---
(add-after 'unpack 'fix-script
  (lambda _
    (substitute* "setup.py"
      (("'scripts': \\['speedometer.py'\\],")
       "'packages': ['.'],"))))
--8<---------------cut here---------------end--------------->8---

[1]: https://github.com/wardi/speedometer/tree/release-2.8