Re: clarification of `rev-list --no-walk ^<rev>`?

"Philip Oakley" [off-list ref] writes:

quoted

The "--no-walk" tells the rev-list machinery "I have only positives;
do not traverse from them AT ALL but just use these positives".
Only under that condition, the order of the positive ends you list
on the command line matters.

What does "--do-walk" do ("Overrides a previous --no-walk"), and when
would it be applied?

Wouldn't 

    $ git cherry-pick --no-walk --do-walk A

end up walking the history behind A and reproducing the history
since the root commit?