Ignore commas in pip show, etc.

What’s the problem this feature will solve? Currently on using pip show on a package with multiple dependencies they are listed comma separated, e.g.:

>pip show mayavi
Name: mayavi
Version: 4.6.0
Summary: UNKNOWN
Home-page: http://docs.enthought.com/mayavi/mayavi/
Author: Prabhu Ramachandran, et. al.
Author-email: [e-mail]
License: BSD
Location: c:\python36_64\lib\site-packages
Requires: apptools, envisage, numpy, pyface, pygments, traits, traitsui, vtk
Required-by:

But if, for example we wish to check the licence for all of the dependencies so copy the last line to pip show with:>pip show apptools, envisage, numpy, pyface, pygments, traits, traitsui, vtk it fails silently on everything but vtk. This could easily lead the user, especially if they are using a pipe to filter the licence lines and remove duplicates, to draw the wrong conclusion.

Describe the solution you’d like It the list processing for pip show and other commands were to add a strip of the comma character rather than the relying user understanding what happened an performing a manual edit then the results would be as intuitively expected.

In the real world example above stripping commas from the target list would have the same effect as >pip show apptools envisage numpy pyface pygments traits traitsui vtk

Alternative Solutions

Additional context

[GadgetSteve]

Added a new issue #6858 to separate the issues, and any PRs, as pointed out above by @chrahunt this is really a separate issue that has been about for a long time.

[GadgetSteve]

Wondering about the scope of the required testing!

1. Test that the desired change works in the specific expected place OR
2. Test all of the places that it will result in a change of behavior, i.e. just about every pip command would be able to accept a comma space separated list as well as a space separated list.