Feature proposal: Pip dry-run

[Nitzan Raz]

I wrote a little script that uses the pip libs to check if `pip install` would "do something" (as in install new stuff).

http://blog.backslasher.net/pip-dry-run.html

I think it'll be a good addition to the pip toolbelt, but I saw that there was such a feature a long time ago and it was deprecated. Was the specific implementation problematic or is it considered "bad practice" by the pip people?

Thanks!