Re: Progress on Mac installation cloning

[Ethan A M. <sf...@us...>]

On Friday, 04 March, 2016 00:02:06 Mojca Miklavec wrote:
> 
> > Are you saying that I should make an /opt/gnuplot directory
> > on the build machine, put the required dynamic libraries there,
> > and tell the gnuplot build that the libraries are in /opt/gnuplot?
> 
> Yes, that would be much better than installing dynamic libraries into /usr/local

I very much disagree with this.
The whole point of shared libraries is that they are, well, _shared_.
When a single copy of the library is shared, that means security fixes, 
library bug-fixes, and upgrades benefit all programs on the system.
If you keep a separate copy for each program then you would have to update
and rebuild each of those separate copies in parallel.  What a headache.


> > And your point is that the dynamic libraries in /opt/gnuplot
> > are less likely to get clobbered than if they are in their
> > "standard" places?
> 
> Yes.

Where "clobbered" can mean "updated or fixed"

> Gnuplot binary alone is in fact not problematic at all, but as soon as
> you start shipping some libraries (like libpng.dylib inside
> /usr/local/lib/libpng.dylib if you wouldn't build it statically for
> some reason) this is just asking for problems later on. (Even if user
> just decides to install MacPorts or HomeBrew later on, libpng.dylib in
> /usr/local/lib will cause numerous headaches for that user and any bug
> reports that the user would try to file would be immediately closed
> with "please remove that library from /usr/local/lib".)

That is the exact opposite of a supportable system layout IMHO.
If there is a bug in the library, that is exactly when you _do_ want a
single shared copy so that fixing the bug benefits all users of the library.

Now it is true that if you manage to build a defective copy of a library
then putting it in /usr/local/lib could harm other programs as well as 
breaking your intended client.  But putting that defective library in your
private directory isn't going to get you a working client either, 
nor would including it permanently in your executable as a static library.

	Ethan