Cabal-1.22 keyed library filepaths

[Edward Z. Yang]

Hey Jens,

The motivation for truncating the names and version was to keep
symbol name sizes manageable even with the addition of the hash,
while giving at least some hint when working with the symbols
directly.  It doesn't seem that this rationale applies for library
names, so it's possible we could separate these (in any case, only
the hash really matters: the package name/version are included
in the hash), but we'd have to figure out where in the current codebase
makes assumptions about this.

Edward

Excerpts from Jens Petersen's message of 2015-01-18 17:54:34 -0800:
> Hi,
> 
> I see that with Cabal-1.22, library paths are now of the form:
> 
>  /usr/lib64/ghc-7.10.0.20141222/direc_3m6Ew9I164U5MIkATLCdb8/
> libHSdirec_3m6Ew9I164U5MIkATLCdb8-ghc7.10.0.20141222.so
> 
> etc.
> 
> Is the 5 character truncation of package names (and no version) necessary?
> It makes it pretty hard to see at a glance what package a particular
> directory or file belongs to and seems there is no easy way to work out the
> package version without referring to the package.conf file/dir.
> 
> If possible I would prefer a filepath format like:
> 
>  /usr/lib64/ghc-7.10.0.20141222/directory-1.2.1.1_3m6Ew9I164U5MIkATLCdb8/
> libHSdirectory-1.2.1.1_3m6Ew9I164U5MIkATLCdb8-ghc7.10.0.20141222.so
> 
> Would that be feasible/make sense?
> 
> Jens