path normalisation in "base"

[René J.V. Bertin]

Hi,

I'd like to understand a bit better why the base layer does path normalisation in a number of places where its use isn't immediately obvious to me, like for instance the action_provides procedure in the port script. If that's not so broad of a question that it cannot be answered with a single, succinct explanation.

I can see how it would probably be required in a sandboxing context, and I have no idea exactly what kind of sandboxing MacPorts does. (I do seem to recall whatever issues it had with e.g. a symlinked $prefix were resolved a while ago.)

To come back to action_provides: if the registry saves a port's "intended" paths (the ones stored in the software image tarball), why do a lookup of the actual/resolved path? That would make it impossible to check which port installs a symlink (to a file or directory installed by itself, some other port, or even to something in system space), regardless of whether there are "unexpected" symlinks in the path, no?

R.