[gentoo-dev] Re: News Item: Portage Dynamic Deps

[Ulrich Mueller]

>>>>> On Wed, 24 Jan 2018, Martin Vaeth wrote:

> Ulrich Mueller <ulm@g.o> wrote:
>> "Runtime dependencies (RDEPEND). These must be installed and usable
>> before the results of an ebuild merging are treated as usable."
>> https://projects.gentoo.org/pms/6/pms.html#x1-770008.1
>>
>> IMHO this implies that the dependencies at merge time are the
>> relevant ones

> IMHO this specifies what is relevant when an emerge merging happens.
> Nothing more, nothing less.

Exactly. RDEPEND is to be evaluated at the time before the package is
merged. For PDEPEND it is even clearer: "These must be installed at
some point before the package manager finishes the batch of installs."

> _If_ one would be willing to interpret it to have a meaning also
> _after_ the emerge, then of course the RDEPEND in PMS can refer to
> the only value which is specified in PMS, i.e. that stored in the
> ebuild

... at the time when the package was merged. You cannot rely on
anything else, because the ebuild may be gone in the meantime.

> (and not in any database which is explicitly not specified by PMS).
> In other words: _If_ one puts any unsaid interpretation into that
> sentence, then this can only be dynamic deps.

No. The only thing that PMS doesn't specify is the special format of
the VDB. However, the spec says that variables must keep their values
between phase functions, which includes pkg_prerm() and pkg_postrm().
By this, *some* sort of storage mechanism must exist.

Ulrich