libpng transition?

Jack Howarth howarth at
Fri Jan 21 11:10:08 PST 2011

On Fri, Jan 21, 2011 at 10:45:36AM -0800, Dan Ports wrote:
> Implicit in here is the assumption that you're always upgrading all of
> your outdated ports at once -- `port upgrade outdated`.
> If you saw a new version of libpng and decided you wanted to upgrade
> it (for all of the exciting new features a graphics library can offer?)
> but not all your other ports, `port upgrade libpng` would happily let
> you do that and leave most of your system broken. 
> I'd be happier if there were a warning that these other ports need to
> be upgraded too or they're going to break. Not sure how we could
> achieve that, though.

   I not referring to that. Rather I am concerned about the case where
libpng and a number of packages that require it are already installed.
If the user does a 'sudo port selfupdate' and 'sudo port outdated', what
insures that none of the packages being upgraded aren't built before the
new soversion of libpng is installed? The absence of any checks for
version dependencies in MacPorts appears to make that impossible. It is
very unfortunate that the depends-lib file doesn't allow for a syntax

depends-lib: port:libpng(>=1.4)


depends-lib: port:libpng(>=1.4.5-1)

such that port could attempt to order the build such that the version
dependencies are met.

> Dan
> -- 
> Dan R. K. Ports              MIT CSAIL      

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