./dev/update_packages.py fails awkwardly if pub is not in your path #64

./dev/update_packages.py [/src/flutter]
Updating cassowary ...
Traceback (most recent call last):
File "./dev/update_packages.py", line 19, in
update(os.path.join(FLUTTER_ROOT, 'packages'))
File "./dev/update_packages.py", line 17, in update
subprocess.check_call(['pub', 'get'], cwd=package_dir)
File "/usr/lib/python2.7/subprocess.py", line 535, in check_call
retcode = call(_popenargs, *_kwargs)
File "/usr/lib/python2.7/subprocess.py", line 522, in call
return Popen(_popenargs, *_kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 710, in init
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory

%pub [/src/flutter]
zsh: command not found: pub