conflicting variants while rebuilding a dependency

[Mojca Miklavec]

Dear Riccardo,

On Sat, 12 Jan 2019 at 19:17, Riccardo Mottola via macports-users
<macports-users at lists.macports.org> wrote:
>
> Hi all!
>
> I get this (Lion 10.7):
>
> -->  Scanning binaries for linking errors
> Could not open /opt/local/lib/libexiv2.26.dylib: Error opening or
> reading file (referenced from /opt/local/lib/libgexiv2.2.dylib)
> --->  Found 1 broken file, matching files to ports
> --->  Found 1 broken port, determining rebuild order
> You can always run 'port rev-upgrade' again to fix errors.
> The following ports will be rebuilt: gexiv2 @0.10.8+python27+python36
> Continue? [Y/n]:
> Error: boost: Variant python27 conflicts with python36
> Error: Unable to open port: Error evaluating variants
> Error: rev-upgrade failed: Error rebuilding gexiv2
> Error: Follow https://guide.macports.org/#project.tickets to report a
> bug.
>
>
> is this a "change" ? my current active port has indeed both variants:
>
> The following ports are currently installed:
>    gexiv2 @0.10.8_1+python27+python36 (active)
>
> So, I suppose that when it was installed, the two python variants were
> possible, but now now anymore?

gexiv2 still has both variants enabled by default. In some ports this
is allowed, but in many it is not, if nothing else because one cannot
run a single configure step that would enable two python versions.

I didn't test, but I assume that you might be able to do
    sudo port install gexiv2
but not
    sudo port install gexiv2 +python27 +python36
if some of the dependencies with python variants are not yet
installed, or waiting for update.

This might well be a bug, or rather an unfortunate coincidence with no
easy workaround.
What happens if you clean all the ports and run
    sudo port install gexiv2
manually instead of waiting for rev-upgrade?

Mojca