[gentoo-dev] Re: Avoiding rebuilds

[Martin Vaeth <martin@mvath.de>]

Steven J. Long <slong@rathaus.eclipse.co.uk> wrote:
>>
>> > It will probably also cause confusion for comaintainers and
>> > collaborators, especially when INSTALL_VERSION points to a version
>> > that has already been removed.
>
> So use another name that can't be confused.

Perhaps there is a misunderstanding: I did not understand that the
confusion is caused by the name, but by the lack of information
about its entries:

For instance, if you bump a version, you must never forget to
check whether this variable needs to be updated.
Moreover, if you want to update that variable, you should
understand precisely why which version is listed here
in order to decide whether a recompile from that version
might be needed with the current bump or not.
This decision is not necessarily easy if the corresponding
referred ebuilds are already in the CVS attic.

Of course, if in doubt, it is a safe strategy to always
remove that variable (it can only cause redundant compilation,
while it can be fatal if you leave a version falsely).

Therefore, an automatism to "forget" this variable automatically
if not changed would be preferrable, but one would need a mechanism
for this (I have only some strange ideas for such a mechanisms:
One could encode the current ebuild version into the name of
that variable; or one could require that the current version
is the first entry in this variable [although, semanatically,
it is ignored and just serves as a "proof" that the ebuild
maintainer checked that variable]).