`emerge` command (like `emerge -vj`) uses the exported customized env variables when install a package, and stores these variables in the '/var/db/pkg/<cate>/<name>-<ver>/environment.bz2' file. However the `emerge --config` drops the exported customized env variables when executing, so I cannot override the previous stored exported variables. This inconsistent behavior is so weird! Either none of them should respect the exported env vars, or both should be, I think. Not sure if it's a special consideration in portage. Reproducible: Always Steps to Reproduce: e.g.: the 'net-misc/keycloak' pkg in my overlay dev branch: https://github.com/bekcpear/ryans-repos/tree/dev/net-misc/keycloak-bin 1. # export KC_DB=postgres 2. # emerge -vj net-misc/keycloak 3. # export KC_DB=dev-file 4. # emerge --config net-misc/keycloak Actual Results: Than, you will see the got KC_DB value by pkg_config is still 'postgres', and can't find a way to override it. Variables that are not stored by the environment.bz2 file cannot be obtained by the pkg_config function either.
This is a side-effect of the PMS requirement that variables set in a given ebuild phase function must be preserved/restored for later phases. https://projects.gentoo.org/pms/8/pms.html#x1-11400011.2 To accomplish this, Portage saves the variables at the end of each function, and restores them before running the next one. In this case, it is treating pkg_config as a "later function". The same behavior happens in pkg_preinst and pkg_postinst when you install a binpkg, for example.
I understand what you mean, that is to say, although the execution time of pkg_config may be far away from the time when the package emerges, and pkg_config may be executed many times after that, each pkg_config operation is designed to be strongly associated with the environment in which the package was installed. Although it is different from what I imagined, it is already understandable. However, if possible, I still recommend considering pkg_config as a tool to modify the package configuration multiple times in subsequent environments.
