Re: New feature: Post-requisites

[Alejandro Colomar (man-pages)]

Hi Paul

On 7/31/22 14:36, Paul Smith wrote:
> On Sun, 2022-07-31 at 11:45 +0200, Alejandro Colomar (man-pages) wrote:
> > > If some new post-requisite "baz" was found while building either
> > > "foo" or "bar", it would be built after those and be as if the user
> > > had invoked "make foo bar baz".
> >
> > What if one runs `make -j foo foo2` and both foo and foo2 have a
> > post-requisite of bar?  `make -j foo foo2 bar` doesn't guarantee that
> > bar will be started after foo2 ends, but this feature would need such
> > a guarantee.
>
> Well, what I was really thinking was that the postrequisites would go
> into their own list.  So the set of "current" goals would be in one
> list and the postrequisites would be added to a new list.  Once all the
> current goals were completed, then make would start working on the new
> list, and any further postrequisites would be added to a new new list.
> Etc. until the "new list" was empty (no more postrequisites were added
> during the last set of builds).

That makes sense to me.  The performance is suboptimal, I think, since 
it needs to wait for all "current" goals even if there was no actual 
dependency to some of them.  But if the implementation is much simpler, 
I think it's a good tradeoff.  Looks good to me.

The ideal solution would be to extend the DAG in some way that includes 
the post-requisites, but that would need an architectural change.

Cheers,

Alex

--
Alejandro Colomar
Linux man-pages comaintainer; http://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/