[oe] [RFD] increased dependency checking

[Vitus Jensen]

Hello Frans,

On Sat, 28 Aug 2010, Frans Meulenbroeks wrote:

> Currently if a package in the DEPENDS list is modified, a package that
> depends on it does not get updated even if explicitly build
> E.g. when I just updated libexif and after that did a bitbake
> mythplugins (which has a DEPENDS on libexif) libexif got build but
> mythplugins did not get rebuild.

First: bitbake isn't make.  So doing it half-automatic is OK.

> This is not really proper. E.g. if the lib changed a .h file the build
> of the using package could fail, but it could easily get unnoticed as
> one will only become aware of this when forcefully rebuilding that
> using package.

In my opinion a change of a header is a change of interface, and a change 
of the package the lib is packed into.  This always requires a bump of PR 
of that package.

> I think we can do better by better exploiting the timestamp.
> E.g. what about doing it this way:

So you don't need to exploit the timestamps, you "just" have to keep the 
dependency chain at the moment a package was built.  On the next run you 
compare the dependency chain and rebuild if a package got a new PV-PR.

This information could be kept in the bitbake cache.  When someone changes
  distro / machine / local conf he has to do the rebuild himself.  after 
all, bitbake isn't make.

Best regards,
    Vitus

-- 
Vitus Jensen, Hannover, Germany, Universe (current)
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