Broken _DEPENDS logic

[Roger Marquis]

>> Found why mailman is trying (and failing) to reinstall postfix and it
>> appears to be a bug in other ports as well.
>>
>> Shouldn't these ports be querying the pkg db rather than checking for a
>> particular file, particularly when the file is incorrectly specified?
>
> Have you read the Porters' Handbook?

Not being a port maintainer, no.

> But, generally, the answer to your question is "no," becuase it is often
> the case that more than one port can serve as a dependency for another
> port. Your suggestion amounts to saying that only one port can satisfy a
> dependency for another port, which is not the case.

Not sure I understand the explanation but to clarify this specific case:
the mail/mailman port's dependency on mail/postfix fails because it look
for an installed file at a specific path without regards for the postfix
port's INST_BASE option.

Roger