[gentoo-user] Re: A Glitch in the Matrix or just another burb of emerge... ;)

[Jonathan Callen]

On 05/10/2016 10:59 PM, Hartmut Figge wrote:
> Jonathan Callen:
>
>> I haven't looked into why gcc 4.9 blocks older versions now, although
>> I know it didn't always do so.
>
> I was bitten by that problem today. First I masked gcc-4.9 so I was able
> to do an emerge @world. Then I commented out the masking of gcc-4.9 and
> tried to emerge it, I got
>
> i5-64 hafi # emerge -pv  gcc
>
> These are the packages that would be merged, in order:
>
> Calculating dependencies... done!
> [ebuild   R    ] sys-devel/gcc-4.9.3:4.9.3::gentoo  USE="cxx fortran
> (multilib) nls nptl openmp sanitize vtv%* (-altivec) (-awt) -cilk -debug
> -doc (-fixed-point) -gcj -go -graphite (-hardened) (-libssp) -multislot
> -nopie -nossp -objc -objc++ -objc-gc -regression-test -vanilla" 39 KiB
> [blocks B      ] <sys-devel/gcc-4.9 ("<sys-devel/gcc-4.9" is blocking
> sys-devel/gcc-4.9.3)
>
> Total: 1 package (1 reinstall), Size of downloads: 39 KiB
> Conflict: 1 block (1 unsatisfied)
>
>  * Error: The above package list contains packages which cannot be
>  * installed at the same time on the same system.
>
>   (sys-devel/gcc-4.9.3:4.9.3/4.9.3::gentoo, ebuild scheduled for merge)
> pulled in by
>     gcc
>     sys-devel/gcc required by @system
>     >=sys-devel/gcc-4.9.3 required by
> (dev-java/icedtea-bin-7.2.6.6-r1:7/7::gentoo, installed)
>
>   (sys-devel/gcc-4.7.4:4.7.4/4.7.4::gentoo, installed) pulled in by
>     sys-devel/gcc:4.7.4 required by @selected
>
> It seems judicious to stay with the masked gcc until the problem is
> fixed or someone offers a solution.
>
> Hartmut
>
>
>


Looking further at the ebuilds in question, it appears that if you wish
to have older versions of GCC installed with >=gcc-4.9, you need to have
USE=multislot on the *newer* versions of gcc (this USE=multislot doesn't
appear to be completely broken like the old USE=multislot was; now the
SLOTs are constant with respect to USE).

-- 
Jonathan Callen