revert: extract actual revert in its own function
With this small refactoring, the computation of the action to perform and the
actual change to the disk happen in different function. This allows extension to
wrap the later in case of need. The initial motivation is the `remotefilelog`
extension that need to prefetch all the file content to be checked out.
hide outer repo
$ hg init
Test case sensitive configuration
$ echo '[Section]' >> $HGRCPATH
$ echo 'KeY = Case Sensitive' >> $HGRCPATH
$ echo 'key = lower case' >> $HGRCPATH
$ hg showconfig Section
Section.KeY=Case Sensitive
Section.key=lower case
Test "%unset"
$ cat >> $HGRCPATH <<EOF
> [unsettest]
> local-hgrcpath = should be unset (HGRCPATH)
> %unset local-hgrcpath
>
> global = should be unset (HGRCPATH)
>
> both = should be unset (HGRCPATH)
>
> set-after-unset = should be unset (HGRCPATH)
> EOF
$ cat >> .hg/hgrc <<EOF
> [unsettest]
> local-hgrc = should be unset (.hg/hgrc)
> %unset local-hgrc
>
> %unset global
>
> both = should be unset (.hg/hgrc)
> %unset both
>
> set-after-unset = should be unset (.hg/hgrc)
> %unset set-after-unset
> set-after-unset = should be set (.hg/hgrc)
> EOF
$ hg showconfig unsettest
unsettest.set-after-unset=should be set (.hg/hgrc)