Should BuildSystem download updated external packages when they are out of date?

Richard Tran Mills rmills at
Fri Oct 2 09:11:40 CDT 2009

BuildSystem Folks (Matt, mainly),

This is not really a problem for me since I know about this behavior already, 
but I note that it can cause significant confusion when has been 
asked to download a package and a very out of date version of that package 
already exists in $PETSC_DIR/externalpackages.  In this case, 
doesn't do anything since the package is already there, but in some cases the 
interfaces have changed and that package isn't actually usable.  For instance, 
if hypre-2.0.0 is present, it won't work with the current petsc-dev, but the 
configure proceeds anyway, even though things won't work unless hypre-2.4.0b 
is downloaded.  In such a case, deleting the hypre-2.0.0 directory and 
re-running will fix the problem, but it seems like this isn't 
very user-friendly and I know that it does cause some confusion.

I am no BuildSystem hacker (I think I've committed a change maybed once, in 
2005?).  Can someone tell me if it is reasonable to make download 
the new package if the old one is too out of date?


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