package.conf should be under /var, not /usr

[igloo]

fhs-2.3 says:

/usr is the second major section of the filesystem. /usr is shareable,
read-only data. That means that /usr should be shareable between various
FHS-compliant hosts and must not be written to. Any information that is
host-specific or varies with time is stored elsewhere.

package.conf is not shareable, as different machines may have different packages installed, so we should put it under /var instead.

[duncan]

Replying to igloo:

package.conf is not shareable, as different machines may have different packages installed, so we should put it under /var instead.

Right. Note that the initial/pristine version of the package db could be stored along with ghc in lib. The first time ghc-pkg registers a new global package then the db should be made under /var. Either the pristine one should be copied to /var or the one in /var should extend the pristine one.

The point is, a binary install should still be relocatable. Instllation should not have to create any global db in /var. That can be defered to runtime rather than install time. Like the way ghc-pkg makes the per-user db on demand.

[igloo]

punting

[duncan]

See also  http://hackage.haskell.org/trac/hackage/ticket/543