Listing the ports that will be upgraded in advance

[René JV Bertin]

> On 19 Feb 2015, at 14:20, Clemens Lang <cal at macports.org> wrote:
> 
> 
> ----- On 19 Feb, 2015, at 13:33, René J.V. Bertin rjvbertin at gmail.com wrote:
> 
>> Had that today on a remote VM which apparently had a borked doxygen install, and
>> which insisted on installing doxygen+docs because that variant exists and the
>> dependent port was requested with that variant. I still don't understand, but
>> finally a `upgrade --force` to reinstall the regular version solved the issue.
> 
> When a port is installed, the variants you pass on the command line will be used
> in all dependent ports as well.
> 
> 
>> Mojca: I've grown the habit to use -n almost all the time to avoid unasked-for
>> upgrading ... but as shown above that doesn't always prevent all upgrading ...
> 
> -n is considered harmful, because you will miss required rebuilds that *must* be
> done before a software can be used again. Passing -n for upgrade may well have
> caused your broken doxygen install. Please do not make using -n a habit unless
> you are very well aware of the risks and can identify and fix the fallout

Possible, but from what I could tell the only that was broken was the registry entry. Doxygen contains only a binary, basically,  and any issues due to -n should haven been caught by the rev-upgrade step before I started on the dependent port. 
Right?

R