port upgrade outdated fails

[Chris Jones]

>> gcc9 default the default when it was release, last year.
>>
>> Its up to you what you do here. either use gcc8, or gcc9. not a mixture of both.
>>
>> Chris
>>
> 
> If the port was built with the gcc8 variant, ‘port upgrade outdated’ shouldn’t change that. Doesn’t make sense.
> 

That is exactly the problem.

Some of your ports are installed with the gcc8 variant. If you did not 
explicitly request this then it must have been the default at the time 
you first installed that port. Since then, port upgrades have preserved 
that choice *even* if the default subsequently changed to gcc9.

Them at some point the default gfortran provider was changed to gcc9, 
when that compiler was added to macPorts after its release.

After this point, when you installed a port for the first time you would 
have used the new default variant again (unless you explicitly ask for 
something else). so you got gcc9.

Bottom line. You have a mixture of gcc8 and gcc9 variants in use, and 
some ports do not support this, as made clear by the message at the 
start of this thread. You have to, for these ports, pick one or the other...

Ball is in your court to fix this.

Chris