From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Bavier Subject: Re: [PATCH 0/2] native-search-paths for GHC Date: Wed, 07 Oct 2015 16:27:11 -0500 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:58921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjwFF-0000sC-LA for guix-devel@gnu.org; Wed, 07 Oct 2015 17:27:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZjwFB-0004Nd-Jb for guix-devel@gnu.org; Wed, 07 Oct 2015 17:27:29 -0400 Received: from smtp7.openmailbox.org ([62.4.1.41]:53084) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjwFB-0004N0-AQ for guix-devel@gnu.org; Wed, 07 Oct 2015 17:27:25 -0400 In-Reply-To: List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org To: Federico Beffa Cc: Guix-devel , federico.beffa@gmail.com On 2015-10-07 11:07, Federico Beffa wrote: > ericbavier@openmailbox.org writes: > >> From: Eric Bavier >> >> The first of these patches lets search-path-as-list function correctly >> when a >> pattern is given and the 'directory file type is specified. >> >> The second adds a native-search-paths field to our ghc package. It >> modifies >> our haskell-build-system to install a package-specific package >> database with >> each haskell library. GHC insists on a binary package cache file >> called >> 'package.cache' to be in each directory listed in GHC_PACKAGE PATH, so >> we >> uniquely name the package database directories, and use a file-pattern >> to add >> those to GHC_PACKAGE_PATH. >> >> The benefit of this over the current situation is that one gets the >> benefit of >> `guix package --search-paths`. Currently, after installing ghc >> packages, the >> user needs to know to manually add >> ~/.guix-profile/lib/ghc-7.8.4/package.conf.d to their >> GHC_PACKAGE_PATH. GHC >> package recipes would no longer need to propagate runtime >> dependencies, and >> 'guix environment' also works nicely out-of-the-box:: >> >> $ guix environment --ad-hoc ghc ghc-attoparsec >> $ ghc-pkg list >> /gnu/store/...-ghc-mtl-2.1.3.1/lib/ghc-7.8.4/ghc-mtl-2.1.3.1.conf.d >> base-4.7.0.2 >> ghc-prim-0.3.1.0 >> integer-gmp-0.5.1.0 >> mtl-2.1.3.1 >> rts-1.0 >> transformers-0.3.0.0 >> /gnu/store/...-ghc-regex-base-0.93.2/lib/ghc-7.8.4/ghc-regex-base-0.93.2.conf.d >> array-0.5.0.0 >> base-4.7.0.2 >> bytestring-0.10.4.0 >> ... >> /gnu/store/4vvmngz1w8ccm7v7mk4f4dxk45834464-ghc-attoparsec-0.13.0.0/lib/ghc-7.8.4/ghc-attoparsec-0.13.0.0.conf.d >> array-0.5.0.0 >> attoparsec-0.13.0.0 >> ... >> >> Though, as you can see in this example, libraries may be listed more >> than >> once. As far as I can tell at this point, that is just an aesthetic >> detail. >> >> Future work might involve filtering build-only library dependencies >> from the >> generated package database. We could probably also remove the ghc >> package >> database creation during profile generation. >> >> I'd be interested in hearing others' thoughts on this approach. > > Hi Eric, > > sounds like a good approach to work around the "package.cache" clash. I > have a couple of questions: > > * If I understand correctly, the configuration files of dependencies > are > copied in a unique directory for each package. Instead of copying > would a symlink work? (There are literally thousands of packages on > Hackage and hopefully Guix will get more of them.) I don't know if symlinking is allowed across store directories, though if it is, that'd be something to try. > * Some Haskell libraries have a rather large list of dependencies. For > this reason I can imagine that in some situations GHC_PACKAGE_PATH > could grow rather long. Not every package would end up with an entry in GHC_PACKAGE_PATH, only those that are installed, or declared inputs. Dependent libraries would be found when GHC examines the package databases of those packages. > This thought made me wonder if there is a > maximum length to the value of environment variables that we could > possibly hit. We've already pushed this quite far. E.g. the hydra package creates a rather sizable PER5LIB path. -- `~Eric