[gentoo-dev] Re: new virtual -- virtual/go to fix go build time dependencies

[Jonathan Callen]

On 03/01/2017 07:18 PM, William Hubbs wrote:
> All,
>
> the dependencies for dev-lang/go need to force a rebuild every time the
> compiler is downgraded or upgraded.
>
> To avoid abusing slot dependencies for dev-lang/go since it is not
> needed at runtime I need to do the following.
>
> I need to introduce virtual/go-1.7.5, virtual/go-1.8 and
> virtual/go-9999. The attachment shows 1.8 but it is the same for all
> versions.
>
> Also, the attached patch needs to be applied to golang-base.eclass.
>
> This is based on the following wiki page:
>
> Ahttps://wiki.gentoo.org/wiki/Project:Quality_Assurance/Subslots#Using_virtuals_to_expose_multiple_ABIs
>
> Any thoughts?
>
> William
>

Unfortunately, this would allow the user to remove all versions of
dev-lang/go before attempting to compile a package using go, as
virtual/go has no RDEPENDs, and only RDEPENDs of DEPENDs are required to
be present (not DEPENDs of DEPENDs).

That is, the following sequence of actions would be perfectly legal,
according to the dependencies:

Merge dev-lang/go
Merge virtual/go
Unmerge dev-lang/go
Merge {package using golang-base.eclass}

While my initial thought was to just add dev-lang/go to the DEPEND in
the eclass (in addition to virtual/go), that doesn't quite work as the
two packages are allowed to get out of sync because virtual/go doesn't
RDEPEND on dev-lang/go at all (so you could install virtual/go for your
current version of dev-lang/go, then upgrade dev-lang/go without
upgrading virtual/go).

-- 
Jonathan Callen