[Toaster] Design - Cancelling builds

[Richard Purdie]

On Thu, 2015-09-03 at 16:11 +0000, Reyna, David wrote:
> The thing is that we have all done exactly that at one time or another
> to stop an errant build, however Bitbake explicitly advises against
> that. The reason is that it is possible that a given task could be
> broken at a state that cannot be recovered from in a subsequent
> build.  
>
> And while that failure state has never been encountered in my
> experience, it is always possible given how fancy bitbake is getting
> around parallel builds and state management, and the actions to
> recover from such a state would probably not be doable from Toaster
> and would require the intervention of the system manager.

Generally bitbake itself is comparatively safe however we have no
guarantees about the underlying build systems in the individual pieces
of software though.

One pathologically bad case is when we run out of disk space, that
usually breaks build directories to the point they're unusable,
depending on where/when it happens. The same thing could happen when
killing builds although the risk is smaller.

Cheers,

Richard