Re: [gentoo-dev] Questions on overlays, repositories and PMS

[Michael Lienhardt <michael.lienhardt@laposte.net>]

Il 23/02/2018 20:37, Alec Warner ha scritto:
> My general observation is that Gentoo is not successful as an organization about deprecating and removing things. One area where Gentoo has done well is in EAPI and in PMS itself, with mostly-clear versioning and standards and whatnot. But in general if something worked 15 years ago, it probably still works today (doubly so for sys-apps/portage).
> 
> There is a different question when building a tool like yours if it is worth the effort to support things that are 15 years old and are possibly not used (particularly in cases where functionality was replaced). I'd recommend starting with the basic implementation and adding support for the 'older' formats when users ask for them; but this is mostly a trade-off in efforts. If your goal is to build 
> a "100% compatible" tool then you will probably need to support these edge cases.

You have a very good point.
I'd like to be complete (it's a side effect of working in formal methods), but it's quite unrealistic as I am the only developer in this project, and it's true that there are few technical design choices that were made in portage that I'd be happier not to implement.
I'd like to implement the /etc/portage/repos.conf system to remove as many hard coded references to /usr/portage in my code as possible.
Moreover, the /etc/portage/repos.conf system looks nice, modular with explicit dependencies and it almost unifies all the repositories (I don't really understand the need of a DEFAULT section).

If possible, I'd rather avoid implementing things that are deprecated, but like you pointed out, few are (portage seems to be always expanding with new/alternative functionalities).
The ones that are, like the /etc/portage/package.keywords file, seem to be still used (I've got a request to support it in my get_installation.sh script).
Additionally, there are two systems that I did not want to implement but had to: the IUSE_IMPLICIT and USE_EXPAND.
I didn't find any good documentation on these systems (nor the PMS nor https://dev.gentoo.org/%7Ezmedico/portage/doc/man/portage.5.html are very clear on the subject -- the PMS is still clearer), I tested a lot and looked at the portage implementation...
I don't understand the reason to implement these systems with bash variables expanded with prefixes, while many of the USE flag manipulation is done with dedicated files (use.*, package.use.*).
It really felt like an old design choice kept there because it worked, but which could be simplified.

On a similar topic, does anyone still have USE-related variables in his /etc/env.d folder? (https://wiki.gentoo.org/wiki/USE_ORDER)
It seems to me that portage's current effort is to have all configuration files in /etc/portage or in the profile.

Best,
Michael Lienhardt