Optional dependencies should not be treated as a "dependency" kind, of which there are only three -- regular, build, and dev. "Optional deps" should instead be handled as a boolean flag, which is what cargo does. A dependency can be both a build dependency and optional simultaneously, but currently cargo-deps will erase one of these.

Optional dependencies can be displayed with a dashed line.

Some of the integration tests evaluate that certain words are present in the stdout output, which can break or change with updates to the logging verbosity. The following tests specifically do this:

integration/update/empty-deps                                                                                                                                                     
integration/u

Right now, when we want to add a common directory to ignore, we need to go to each integration and add an item. Adding support for some common global ignores would be really useful. Some common directories to ignore are often:

vendor/
test/
testdata/
hack/