[Aptitude-devel] Bug#804103: no method to bulk unmark forbid-version

[積丹尼 Dan Jacobson]

Say one has
# aptitude search ~i|grep ^iF
iF  perl                            - Larry Wall's Practical Extraction and Repo
iF  perl-base                       - minimal Perl system
iF  perl-doc                        - Perl documentation

Our goal today is to just remove the forbid-version marking, nothing
else.

Man page says

       forbid-version
           Forbid a package from being upgraded to a particular version. This
           will prevent aptitude from automatically upgrading to this version,
           but will allow automatic upgrades to future versions. By default,
           aptitude will select the version to which the package would
           normally be upgraded; you may override this selection by appending
           "=<version>" to the package name: for instance, "aptitude
           forbid-version vim=1.2.3.broken-4".

           This command is useful for avoiding broken versions of packages
           without having to set and clear manual holds. If you decide you
           really want the forbidden version after all, "aptitude install
           <package>" will remove the ban.

OK, we see there is no simple way to remove the forbid-version marking,
other than using the install command.

Well if one does
# aptitude install perl perl-base perl-doc
One might be met with one after another uncomfortable choices, all of
which one rejects, as they involve removing packages.

So now trying one at a time
# aptitude install perl
# aptitude install perl-doc
# aptitude install perl-base

We are still met with one after another dangerous choices,
finally reaching one that will just leave everything intact.

And indeed we finally reach our goal of just removing the forbidden
notation.

However it takes
* Manual intervention, whereas
# aptitude forbid-version perl perl-base perl-doc
didn't.
And
* many times more work. Also dangerous.

Therefor aptitude needs a unmarkforbid, just like unmarkauto.