See FL-6885. In this case, XDG_CACHE_HOME, when exported, is able to enter the ebuild build environment and cause go and other compilers to fail.
Gentoo has a workaround for this problem in the form of xdg_environment_reset, a function defined in xdg-utils.eclass.
However, it seems more reasonable that Portage would ensure a minimal, sane environment for building packages and not allow any potentially problematic or compile-impacting environment variables to enter the build environment. This can cause a variety of problems as documented in FL-6885. If some kind of whitelisting or blacklisting currently exists for environment variables, then it doesn't appear to be sufficient.
- is blocked by
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FL-9590 Setting XDG_CACHE_HOME breaks dev-python/pygobject
- Closed
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FL-9591 Setting XDG_CACHE_HOME breaks net-dns/avahi
- Closed
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FL-9594 Setting XDG_CACHE_HOME breaks dev-libs/libxmlb
- Closed
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FL-9595 Setting XDG_CACHE_HOME breaks x11-libs/bamf
- Closed
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FL-9596 Setting XDG_CACHE_HOME breaks media-libs/gegl
- Closed
-
FL-9597 Setting XDG_CACHE_HOME breaks media-libs/libmypaint
- Closed
-
FL-9598 Setting XDG_CACHE_HOME breaks x11-libs/pango
- Closed
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FL-9589 Setting XDG_CACHE_HOME breaks several ebuilds
- Closed
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FL-9303 Portage: support chroot with only critical device nodes
- Work Queue
- relates to
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FL-6885 XDG_CACHE_HOME env var allowed inside ebuild environment, breaking go
- Closed