Facet parameter needs to be maintained when sorting search results

[Kathy Lussier]

Evergreen version: all

This issue was originally reported by Jason Stephenson in https://bugs.launchpad.net/evergreen/+bug/1028560.

When you limit your search results using a facet and then click to sort the results, you are no longer limiting by facet. For example, if I do a search for Harry Potter in the MVLC catalog, I get 409 results. If I then click on the Topic Subject facet for wizards, I get 156 results. If I then choose to sort by title, I'm back to 409 results.

Jason originally fixed this issue by adding a hidden field for the facet that would maintain the parameter while sorting. However, the fix had the unintended consequence of maintaining the facet when a new search is launched - https://bugs.launchpad.net/evergreen/+bug/1091659.

To fix that problem, we then removed the hidden field with the facet parameter, but we are still left with the original problem that sorting a search results list removes the facet parameter, which is unexpected. We need a way to maintain the parameter in sorting, but not when launching a new search.

Note that this is similar to https://bugs.launchpad.net/evergreen/+bug/1206593, where we want to maintain the depth parameter in sorting, but probably do not want to maintain it for a new search.

[Kathy Lussier (klussier)]

Marking this as a duplicate of https://bugs.launchpad.net/evergreen/+bug/1206593. I'll change the title there so that it covers all types of parameters, not just the depth parameter.