--package-cache

gistfile1.txt

"--package-cache"

- a new "pip install" config option that offers name-based (i.e. not url-based) caching.
- the "--download-cache" option would stay as it is, and not be altered
- the package-cache dir would just contain packages (e.g. "nose-1.2.tar.gz", or lxml-2.5[..].whl), anything you've installed while using it.
- the package-cache would be turned off by default, since the user assumes a certain amount of risk/responsibility in using it (no hash checking)
- the package-cache (if turned on) would be checked prior to using the PackageFinder (which searches pypi and findlinks)
    (if the req was "nose", any nose version in the package-cache would "win", unless --upgrade is specified)
- package-cache offers an alternative to this workflow:
    - pip install -d DIR PACKAGES
    - pip install --no-index --find-links=DIR PACKAGES
- "--package-cache" could be used with "--download-cache", but to no advantage most of the time.  the only case I can imagine it would help:
     - you've never used "--package-cache" before, but you have a download-cache
     - the first attempt at using package-cache would benefit from an existing download-cache.