Improve outdated ghc-pkg cache warning

Sometimes you get this:

WARNING: cache is out of date: /home/user/.ghc/x86_64-linux-7.8.3/package.conf.d/package.cache.
Use 'ghc-pkg recache' to fix

The warning is correct but a bit confusing, because running ghc-pkg recache does nothing here: It will by default update your global package DB, and the DB the warning is about will still be out of date.

This seems to have frustrated others as well: https://gist.github.com/mcandre/5789498

I suggest we make the message more clear: You might have to pass --user to update this cache file.

Trac metadata

Trac field	Value
Version	7.8.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	ghc-pkg
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	nh2
Operating system
Architecture

mentioned in issue #7990 (closed)

changed milestone to %7.10.1

changed weight to 5

added Tbug Trac import ghc-pkg labels

Sounds like a good idea to me. Would someone like to create and validate a patch?

Simon

removed milestone

Moving to 7.12.1 milestone; if you feel this is an error and should be addressed sooner, please move it back to the 7.10.1 milestone.

Trac metadata

Trac field	Value
Differential revisions	→ D658

mentioned in commit e7fab334

closed

Merged, thanks!

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

changed milestone to %8.0.1

Milestone renamed

added Pnormal label