Gentoo Archives: gentoo-dev

From: David Leverton <levertond@××××××××××.com>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] [pre-GLEP] Optional runtime dependencies via runtime-switchable USE flags
Date: Fri, 22 Jun 2012 18:31:18
In Reply to: Re: [gentoo-dev] [pre-GLEP] Optional runtime dependencies via runtime-switchable USE flags by Ian Stakenvicius
Ian Stakenvicius wrote:
> Technically it could, but the issue here would be what you are going > to do with a has_version check on an IUSE_RUNTIME dep -- the package > should do filesystem-identical installs no matter what status of > IUSE_RUNTIME flags, so whatever one would do with a has_version check > would have to not change any part of the build or installation.
In principle it would be used for more or less the same thing as it would in a dependency, i.e. check whether the runtime-only dependencies for that feature are satisfied - the difference being that the package can specify arbitrary if-yes and if-no behaviours, rather than just "fail the dependency resolution" or not. (Modulo the problem being discussed in this subthread, that a "no" answer isn't reliable.) For example, some tool used during the build might have a "slow" mode that always works, and a "fast" mode that requires some other program to be installed and that has to be requested explicitly. So the package that uses the tool might want to do something like src_compile() { if has_version dev-util/buildtool[fast]; then buildtool --fast else buildtool fi }