Exception when version is not specified in requirements.txt

[zerthimon]

It would be nice if devpi-builder could install the latest version of requred package, when no version is specified for it ...

Traceback (most recent call last):
  File "/usr/local/bin/devpi-builder", line 11, in <module>
    sys.exit(main())
  File "/usr/local/lib/python2.7/dist-packages/devpi_builder/cli.py", line 105, in main
    packages = requirements.read(args.requirements)
  File "/usr/local/lib/python2.7/dist-packages/devpi_builder/requirements.py", line 41, in read
    _extract_project_version(requirement) for requirement in pkg_resources.parse_requirements(input_file)
  File "/usr/local/lib/python2.7/dist-packages/devpi_builder/requirements.py", line 27, in _extract_project_version
    raise ValueError('Version specification is missing for "{}".'.format(requirement))
ValueError: Version specification is missing for "websocket-client".

[theMarix]

This is an interesting suggestion. I have actually had this use-case myself before. But it vanished because we now pip-compile all requirements used in our tests.

The tricky part about adding this feature is that I there was a reason why it currently is not allowed. We want to make sure that we don't accidentally build a wrong version. E.g. when automatically building all packages that passed a defined clearance process. So it is essential for use to retain the old behaviour.

If it is possible to get both behaviours – enabling the user to select the desired one – without adding too much complexity to the code base that would be great, though.