bail if any custom profile-formats entries are defined in layout.conf

[radhermit]

In this context, bailing would mean logging a repo initialization error and exiting.

Unlike what was done in pkgcore, this time around it's probably worth forcing people wanting such features to sponsor their inclusion in the spec and development. I don't think it's feasible to continue implementing features that are mainly described on a semi-obscure man page.

This should mostly be an issue for overlays as portage has (ab)used profile-formats for years in order to avoid doing the work to get features into the spec and thus have meaningful discussions about them.

[radhermit]

Note that this currently bails if any values are defined as the default value pms isn't meant to be used by itself for regular repos and is only used when tacking extensions on top of it.

Also, it could be better to conditionally bail if profiles are accessed at all when any custom extensions are set as technically accessing repo data that doesn't relate to profiles should work as expected in most cases (e.g. generating repo pkg metadata), but this method is much cleaner to implement, will get user's attention more abruptly, and perhaps spur some action to be taken (in the next decade or two).

[radhermit]

Finally, as a future comment to those running into this when targeting overlays using custom profile-formats (e.g. running pkgcruft scan or pk repo metadata regen), please use this as an impetus to ask for and/or work towards adding profile features you feel are missing to the spec. Portage's use of profile-formats has gone on far too long and has avoided defining even the most basic ones in the spec.