[gentoo-pms] A way for trying to prevent useless rebuilds

[gentoo-pms] A way for trying to prevent useless rebuilds

[Pacho Ramos]

This question comes to my mind every time a developer decides to
drop/add a USE flag to ebuilds like gcc/webkit-gtk/libreoffice... 

I think that we should have a file (like used for category movements) to
let PM know how to handle this situation. 

For example, 
category/foo-1.0 has a "gnome" USE flag but, later, that one is dropped:
-> If it is now *enabling* that support always, our file could have
something like:
category/foo gnome + -> that would mean that, when "gnome" USE flag is
NOT found, portage assumes it as being enabled, that will mean that
people having previously "gnome" enabled wouldn't need to rebuild the
package

... and the opposite

What do you think?

Thanks

Re: [gentoo-pms] A way for trying to prevent useless rebuilds

[Michał Górny]

[-- Attachment #1: Type: text/plain, Size: 1302 bytes --]

Dnia 2013-07-25, o godz. 21:15:48
Pacho Ramos <pacho@gentoo.org> napisał(a):

> This question comes to my mind every time a developer decides to
> drop/add a USE flag to ebuilds like gcc/webkit-gtk/libreoffice... 
> 
> I think that we should have a file (like used for category movements) to
> let PM know how to handle this situation. 
> 
> For example, 
> category/foo-1.0 has a "gnome" USE flag but, later, that one is dropped:
> -> If it is now *enabling* that support always, our file could have
> something like:
> category/foo gnome + -> that would mean that, when "gnome" USE flag is
> NOT found, portage assumes it as being enabled, that will mean that
> people having previously "gnome" enabled wouldn't need to rebuild the
> package
> 
> ... and the opposite
> 
> What do you think?

I'd go for reusing USE dependency defaults syntax, that is:

  category/foo gnome(+)

and:

  category/foo gnome(-)

And honestly, I have no idea how safe is that. We'd probably need
version ranges to use it effectively and safely, e.g.

  ~category/foo-2..4 gnome(+)

No idea if and how this should interact with USE dependency defaults
in other packages.

Ciaran will probably have more doubts.

> 
> Thanks
> 
> 
> 



-- 
Best regards,
Michał Górny

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 966 bytes --]

Re: [gentoo-pms] A way for trying to prevent useless rebuilds

[Pacho Ramos]

El sáb, 27-07-2013 a las 00:22 +0200, Michał Górny escribió:
> I'd go for reusing USE dependency defaults syntax, that is:
> 
>   category/foo gnome(+)
> 
> and:
> 
>   category/foo gnome(-)

Nice, I was thinking in that syntax when suggesting this ;)

> 
> And honestly, I have no idea how safe is that. We'd probably need
> version ranges to use it effectively and safely, e.g.
> 
>   ~category/foo-2..4 gnome(+)
> 

I think this only makes sense when a USE flag is changed without
bump/revbump as, otherwise, people will get a rebuild anyway, then:
=category/foo-1.x gnome(+)

should work

> No idea if and how this should interact with USE dependency defaults
> in other packages.
> 
> Ciaran will probably have more doubts.
> 

I have seen sometimes people suggesting to manually edit VDB to change
the USE flag if wanting to prevent rebuild (I remember this hack for a
change in USE flags that affected a ton of kde related packages years
ago). My idea would be that this "editing" should be done by portage (or
PM) and, then, this should be a two steps process:
1. First one should be used to change VDB
2. Second one would be to do the usual dep calculation with new VDB
information