Ticket #539: depends.patch

Thu Mar 26 20:51:09 GMT 2009  Ganesh Sittampalam <ganesh@earth.li>
  * add dependency reporting command

New patches:

[add dependency reporting command
Ganesh Sittampalam <ganesh@earth.li>**20090326205109] {
hunk ./Distribution/Client/List.hs 6
+--                    Ganesh Sittampalam 2009
hunk ./Distribution/Client/List.hs 14
-  list, info
+  list, info, depends
hunk ./Distribution/Client/List.hs 45
-         ( ListFlags(..), InfoFlags(..) )
+         ( ListFlags(..), InfoFlags(..), DependsFlags(..) )
hunk ./Distribution/Client/List.hs 55
+import Data.Map
+         ( Map )
+import qualified Data.Map as Map
hunk ./Distribution/Client/List.hs 59
-         ( listToMaybe, fromJust, fromMaybe, isJust, isNothing )
+         ( listToMaybe, fromJust, fromMaybe, isJust, isNothing, catMaybes )
+import Data.Set
+         ( Set )
+import qualified Data.Set as Set
hunk ./Distribution/Client/List.hs 133
+depends :: Verbosity
+        -> PackageDB
+        -> [Repo]
+        -> Compiler
+        -> ProgramConfiguration
+        -> DependsFlags
+        -> [UnresolvedDependency] --FIXME: just package names? or actually use the constraint
+        -> IO ()
+depends verbosity packageDB repos comp conf dependsFlags deps = do
+  AvailablePackageDb available _ <- getAvailablePackages verbosity repos
+  deps' <- IndexUtils.disambiguateDependencies available deps
+  Just installed <- getInstalledPackages verbosity comp packageDB conf
+  let deps'' = [ name | UnresolvedDependency (Dependency name _) _ <- deps' ]
+  let pkgs = (PackageIndex.allPackages installed
+             ,PackageIndex.allPackages available)
+      pkgsinfo = map (uncurry mergePackageInfo) $ uncurry mergePackages pkgs
+
+  let fwdmap, revmap :: Map PackageName (Set PackageName)
+      fwdmap = Map.fromList [(pkgname pkginfo, Set.fromList (dependencyNames pkginfo)) | pkginfo <- pkgsinfo ]
+      revmap = Map.fromListWith Set.union [(name2, Set.singleton name1) | (name1, names) <- Map.assocs fwdmap, name2 <- Set.elems names]
+      closeOnce mp = Map.fromListWith Set.union [(name1, Set.unions (names:namess)) | (name1, names) <- Map.assocs mp,
+                                                                                      let namess = catMaybes $ map (flip Map.lookup mp) (Set.elems names)]
+      close mp = let mp' = closeOnce mp in if mp == mp' then mp else close mp'
+
+  let maptouse = (if fromFlag (dependsRecursive dependsFlags) then close else id) $
+                 if fromFlag (dependsReverse dependsFlags) then revmap else fwdmap
+
+  let names = Set.unions $ catMaybes $ map (flip Map.lookup maptouse) deps''
+
+  putStrLn $ unwords $ map (\(PackageName n) -> n) $ Set.elems names
+
hunk ./Distribution/Client/List.hs 199
+dependencyNames :: PackageDisplayInfo -> [PackageName]
+dependencyNames = map (\(Dependency name _) -> name) . dependencies
+
hunk ./Distribution/Client/Setup.hs 23
+    , dependsCommand, DependsFlags(..)
hunk ./Distribution/Client/Setup.hs 423
+-- ------------------------------------------------------------
+-- * Depends flags
+-- ------------------------------------------------------------
+
+data DependsFlags = DependsFlags {
+    dependsRecursive :: Flag Bool,
+    dependsReverse :: Flag Bool,
+    dependsVerbosity :: Flag Verbosity
+  }
+
+defaultDependsFlags :: DependsFlags
+defaultDependsFlags = DependsFlags {
+    dependsRecursive = toFlag False,
+    dependsReverse = toFlag False,
+    dependsVerbosity = toFlag normal
+  }
+
+dependsCommand  :: CommandUI DependsFlags
+dependsCommand = CommandUI {
+    commandName         = "depends",
+    commandSynopsis     = "List dependencies of a package.",
+    commandDescription  = Nothing,
+    commandUsage        = usagePackages "depends",
+    commandDefaultFlags = defaultDependsFlags,
+    commandOptions      = \_ -> [
+        optionVerbosity dependsVerbosity (\v flags -> flags { dependsVerbosity = v })
+
+        , option [] ["recursive"]
+            "Follow dependencies recursively"
+            dependsRecursive (\v flags -> flags { dependsRecursive = v })
+            trueArg
+
+        , option [] ["reverse"]
+            "Find dependencies of the given package"
+            dependsReverse (\v flags -> flags { dependsReverse = v })
+            trueArg
+
+        ]
+  }
+
+instance Monoid DependsFlags where
+  mempty = defaultDependsFlags
+  mappend a b = DependsFlags {
+    dependsRecursive = combine dependsRecursive,
+    dependsReverse = combine dependsReverse,
+    dependsVerbosity = combine dependsVerbosity
+  }
+    where combine field = field a `mappend` field b
+
hunk ./Main.hs 25
+         , DependsFlags(..), dependsCommand
hunk ./Main.hs 47
-import Distribution.Client.List             (list, info)
+import Distribution.Client.List             (list, info, depends)
hunk ./Main.hs 125
+      ,dependsCommand         `commandAddAction` dependsAction
hunk ./Main.hs 237
+dependsAction :: DependsFlags -> [String] -> GlobalFlags -> IO ()
+dependsAction dependsFlags extraArgs globalFlags = do
+  pkgs <- either die return (parsePackageArgs extraArgs)
+  let verbosity = fromFlag (dependsVerbosity dependsFlags)
+  config <- loadConfig verbosity (globalConfigFile globalFlags) mempty
+  let configFlags  = savedConfigureFlags config
+      globalFlags' = savedGlobalFlags    config `mappend` globalFlags
+  (comp, conf) <- configCompilerAux configFlags
+  depends verbosity
+          (configPackageDB' configFlags)
+          (globalRepos globalFlags')
+          comp
+          conf
+          dependsFlags
+          [ UnresolvedDependency pkg []  | pkg <- pkgs ]
+
}

Context:

[TAG 0.6.2
Duncan Coutts <duncan@haskell.org>**20090219130720] 
[Update the README
Duncan Coutts <duncan@haskell.org>**20090219130705] 
[Add missing other-modules
Duncan Coutts <duncan@haskell.org>**20090218235206] 
[Add extra assertion into the top down dep planner
Duncan Coutts <duncan@haskell.org>**20090218234650] 
[Bump version to 0.6.2
Duncan Coutts <duncan@haskell.org>**20090218231016] 
[Update changelog for 0.6.2 release
Duncan Coutts <duncan@haskell.org>**20090218230918] 
[Tweaks to the bootstrap script
Duncan Coutts <duncan@haskell.org>**20090218223943
 Update Cabal lib version to 1.6.0.2
 Implement a couple shell script coding style recommendations.
] 
[Disable the upgrade command for now.
Duncan Coutts <duncan@haskell.org>**20090218221752] 
[Add warnings in the case that no remote servers have been specified
Duncan Coutts <duncan@haskell.org>**20090216181424
 It's not strictly an error but it can be rather confusing.
] 
[Put an explanation of the config file format at the top in comments.
Duncan Coutts <duncan@haskell.org>**20090215190817] 
[Change the field order in the initial config file.
Duncan Coutts <duncan@haskell.org>**20090215190727
 Also update the name of one excluded field.
] 
[Put the default logging and reporting setting in the initial config file.
Duncan Coutts <duncan@haskell.org>**20090215190524] 
[Complete the implementation of --build-summary=TEMPLATE
Duncan Coutts <duncan@haskell.org>**20090215190254
 Actually respect the new flag. It's actually a list of template files
 and all specified files get written to. This allows us to specify
 a default build log file and also have the user write to extra ones.
 The summary file template can contain $pkgid $compiler etc.
] 
[Rearrange user interface for build logging
Duncan Coutts <duncan@haskell.org>**20090215185800
 The new options (as described in ticket #501) are:
   --build-summary=TEMPLATE
   --build-log=TEMPLATE
   --remote-build-reporting=LEVEL
   where LELVEL `elem` [none,anonymous,detailed]
] 
[always check environment variables for HTTP proxy first
Ganesh Sittampalam <ganesh.sittampalam@credit-suisse.com>**20090210230736] 
[Improve the cabal update notice
Duncan Coutts <duncan@haskell.org>**20090209211844] 
[Don't report that packages are cached at the default verbosity level
Duncan Coutts <duncan@haskell.org>**20090209201228
 It's just not that useful. Report it at -v verobisty level, and
 change the text and formatting.
] 
[Fix #490, unpack now gives a proper error message.
Andrea Vezzosi <sanzhiyan@gmail.com>**20090208165240
 Ignore-this: 358dd291624f8858a52ae2ff27a7e0c2
] 
[Use the new withTempDirectory function
Duncan Coutts <duncan@haskell.org>**20090202012255
 In particular it means that install will unpack packages into
 different temp dirs on each invocation which means that running
 install on the same package for different compilers at the same
 time should not clash. This is quite useful for testing.
] 
[Add compat withTempDirectory function
Duncan Coutts <duncan@haskell.org>**20090202011917
 This is already in Cabal HEAD but we cannot use that yet
] 
[Add homepage and bug-reports fields to .cabal file
Duncan Coutts <duncan@haskell.org>**20090201225021] 
[Remove the prefernece and cabal lib version flags from the InstallFlags
Duncan Coutts <duncan@haskell.org>**20090126012412
 They are now in the ConfigExFlags instead.
] 
[Change the install and configure modules to use the extended config flags
Duncan Coutts <duncan@haskell.org>**20090126011942] 
[Add ConfigExFlags into the configure, install and upgrade commands
Duncan Coutts <duncan@haskell.org>**20090126010918
 Not yet passed all the way through.
] 
[Add ConfigExFlags and related command
Duncan Coutts <duncan@haskell.org>**20090126010132
 This is for configure flags that we use in the configure command in the
 cabal command line tool that are not present in runghc Setup configure
 command line interface. These are flags that we are moving from the
 install command, so that we can also use them for the configure command.
 Initially it's just the flags for specifying package version preferences
 and  the cabal library version. We'll add constraints later.
] 
[Remove unnecessary qualified use of ConfigFlags
Duncan Coutts <duncan@haskell.org>**20090126003951] 
[Make configure use the dependency resolver
Duncan Coutts <duncan@haskell.org>**20090125170951
 This means it makes smarter decisions and also decions that are more
 consistent with those taken by the install command.
] 
[Update HTTP dep in the bootstrap script
Duncan Coutts <duncan@haskell.org>**20090123160700] 
[Improve error message when ghc or ghc-pkg are mismatched or not found 
Duncan Coutts <duncan@haskell.org>**20090123160550] 
[Don't use grep -e, solaris does not like it
Duncan Coutts <duncan@haskell.org>**20090123160443] 
[Fix some FIXMEs and do some TODOs in the list command
Duncan Coutts <duncan@haskell.org>**20090123004810
 Now properly prints if the haddock docs are installed and if the
 tarball is cached. It did print them before but it was lying.
] 
[Add initial implementation of cabal info
Duncan Coutts <duncan@haskell.org>**20090119025202
 It provides more detailed information on a particular package.
 Still a few TODOs. Fixes #361, #449 and #456.
] 
[Only print the config file location for the global --help
Duncan Coutts <duncan@haskell.org>**20090116175900] 
[Update to using HTTP-4000.x
Duncan Coutts <duncan@haskell.org>**20090116135646
 This should fix a long-standing bug with http proxies (ticket #352)
 It should also make downloads faster, or at least use less memory.
] 
[Parse compiler field from old config files correctly
Duncan Coutts <duncan@haskell.org>**20090116002851
 Really old versions of cabal-install generated a default config
 containing "compiler: GHC". Sadly the new way we generate the
 config file parser from the command line parser means we end up
 with a case-sensitive parser as it only matches the exact
 command line flags. So we hack it and add in a traditional
 parser for that field only. Really the command line and config
 file infrastructure needs rewriting again. Sigh.
] 
[Improve the printing of config file field parse error messages
Duncan Coutts <duncan@haskell.org>**20090116001421] 
[Read install dirs correctly from old-style .cabal/config files
Duncan Coutts <duncan@haskell.org>**20090116001321
 Should fix ticket #365
] 
[Note in the README that zlib needs the zlib C lib package
Duncan Coutts <duncan@haskell.org>**20090116000541] 
[Traditional /bin/sh portability fixes for bootstrap.sh
Duncan Coutts <duncan@haskell.org>**20090115113227] 
[More improvments to the bootstrap.sh script
Duncan Coutts <duncan@haskell.org>**20090115110612] 
[Rewrite the bootstrap.sh script
Duncan Coutts <duncan@haskell.org>**20090115102210
 Hopefully more useful and more robust. In particular it does not
 download and install packages where suitable versions are already
 installed. It also checks for deps.
] 
[Don't add installed constraints system packages that are not installed
Duncan Coutts <duncan@haskell.org>**20090114143540
 In particular fixes a problem (ticket #439) where we required the
 installed version of ghc-prim with compilers that do not have that
 package such as ghc-6.8 and older, hugs, nhc, lhc etc.
] 
[cabal update now reports if a newer version of cabal-install is available
Duncan Coutts <duncan@haskell.org>**20090114133220] 
[Warn if a package index from a remote repo is 15 days or older
Duncan Coutts <duncan@haskell.org>**20090114124827
 For example it will print:
 Warning: The package list for 'hackage.haskell.org' is 16 days old.
 Run 'cabal update' to get the latest list of available packages.
] 
[Don't display the category in cabal list output
Duncan Coutts <duncan@haskell.org>**20090114003549
 It is probably not sufficiently useful to justify the space it takes.
] 
[In cabal list, always display available and installed versions
Duncan Coutts <duncan@haskell.org>**20090114003329
 Previously we omitted the line if it was not installed, or was
 not available. However that confused people because it was not
 obvious that it would list both. Now it shows something like:
  * foo
        Latest version available: 1.0
        Latest version installed: [ Not installed ]
] 
[Print the location of the config file in the global --help
Duncan Coutts <duncan@haskell.org>**20090113192215
 Ticket #413
] 
[Improve the cabal --help output
Duncan Coutts <duncan@haskell.org>**20090113192058
 Put the general info message at the top and make the explanation of
 installing a hackage package somewhat clearer.
] 
[Display examples in cabal install --help
Duncan Coutts <duncan@haskell.org>**20090113161426
 Examples: 
   cabal install                     Package in the current directory
   cabal install foo                 Package from the hackage server
   cabal install foo-1.0             Specific version of a package
   cabal install 'foo < 2'           Constrained package version
] 
[Print a newline after entering upload password
Duncan Coutts <duncan@haskell.org>**20090113142604
 So we end up with:
   Hackage password: 
   Uploading test.tar.gz...
 rather than:
   Hackage password: Uploading test.tar.gz...
] 
[Respect the --package-db flag when compiling Setup.hs
Duncan Coutts <duncan@haskell.org>**20081221184755
 Fixes ticket #394.
] 
[Use a more precise package substitution test in improvePlan
Duncan Coutts <duncan@haskell.org>**20081219215922
 This is where we take a valid plan and we "improve" it by swapping
 installed packages for available packages wherever possible. This
 change is to the condition we use in deciding if it is safe to use
 the installed package in place of a reinstall. Previously we checked
 that the dependencies of the installed version were exactly the same
 as the dependencies we were planning to reinstall with. That was
 valid but rather conservative. It caused problems in some situations
 where the installed package did not exactly match the available
 package (eg when using development versions of a package or of ghc).
 What we do now is test if the extra constraints implied by selecting
 the installed version are consistent with the existing set of
 constraints. This involves threading the constraint set around. In
 theory this should even cope with adding additional packages to the
 plan as a result of selecting an installed package.
] 
[Use installed constraints instead of hiding versions of the base package
Duncan Coutts <duncan@haskell.org>**20081219193740
 We want to stop cabal-install from accidentally trying to upgrade
 the base package since this doesn't work in most cases. We used to
 achieve that by deleting the base package from the available package
 index. We now do it by leaving the package index as is and instead
 adding a constraint that we pick only an installed version of base.
 This is a nicer hack and has the potential to give better error
 messages.
] 
[Extend the invariant on the Constraints ADT
Duncan Coutts <duncan@haskell.org>**20081219192309
 It now carries around the original version of the database
 purely so that it can do a much more extensive consistency
 check. Packages are never gained or lost, just transfered
 between pots in various slightly tricky ways.
] 
[Fix constraint set handling for installed constraints
Duncan Coutts <duncan@haskell.org>**20081219182328
 A rather subtle bug. The code was actually correct but the transitionsTo
 assertion was not accounting for a transition between the case where
 a package's available version had been excluded and then the whole thing
 got excluded by a version constraint. It counted one side as a loss
 without a corresponding gain on the other side.
] 
[Add a install/upgrade --preference='foo < 2' flag
Duncan Coutts <duncan@haskell.org>**20081218213849
 This behaves just like the preferred-versions file in the hackage index
 but it can be specified on the command line or in a config file.
] 
[Generalise the way preferences are specified to the resolver
Duncan Coutts <duncan@haskell.org>**20081218204917
 We still provide a default global policy, but now we give a
 list of per-package preferences which can be on the version
 or installed state. Later preferences override earlier ones.
] 
[Workaround for a url parsing bug that breaks http proxies that need auth
Duncan Coutts <duncan@haskell.org>**20081218165541
 Diagnosis and patch from Valery V. Vorotyntsev.
] 
[Implement cabal install --constraint=
Duncan Coutts <duncan@haskell.org>**20081216235032
 Connect up the existing user interface with the new dep resolver api.
] 
[Have the dep resolver take constraints and targets separately
Duncan Coutts <duncan@haskell.org>**20081216233446] 
[Add PackageInstalledConstraint to the PackageConstraint type
Duncan Coutts <duncan@haskell.org>**20081215224538
 This should be useful for things like preventing upgrading
 the base package for ghc.
] 
[A bit more renaming in the top down resolver
Duncan Coutts <duncan@haskell.org>**20081215224324] 
[Take preferences into account in the bogus resolver
Duncan Coutts <duncan@haskell.org>**20081215221728] 
[Mostly renaming and trivial refactoring
Duncan Coutts <duncan@haskell.org>**20081215221034] 
[Change the dep resolver interface to pass constraints separately from targets
Duncan Coutts <duncan@haskell.org>**20081215215634
 This lets us specify constraints for packages that are not targets.
] 
[Rename and rearrange the PackagePreferences type
Duncan Coutts <duncan@haskell.org>**20081215204836] 
[Don't re-export PackageName from Distribution.Client.Dependency
Duncan Coutts <duncan@haskell.org>**20081215203617
 It used to be a type alias.
] 
[Use the Platform type rather than passing around the OS and Arch separately
Duncan Coutts <duncan@haskell.org>**20081215202856] 
[Bump version to 0.6.1
Duncan Coutts <duncan@haskell.org>**20081210224713] 
[Tidy up the unpack code
Duncan Coutts <duncan@haskell.org>**20081210223633
 Also fix a bug for tar files that contain entries for files
 without preceding entries for the directories they are in.
] 
[Clean up the code in Main
Duncan Coutts <duncan@haskell.org>**20081210223242
 Make the names more regular and set up the various flags
 in a more regular way.
] 
[Use (\_ -> []) instead of mempty to avoid funky Monoid instance
Duncan Coutts <duncan@haskell.org>**20081210223106
 This would let us build with ghc-6.4 or nhc if it were not for other issues.
] 
[Fix warning aobut -fffi in OPTIONS pragma
Duncan Coutts <duncan@haskell.org>**20081203005449] 
[Mention where files get downloaded to at verbosity level verbose
Duncan Coutts <duncan@haskell.org>**20081203004427] 
[Implement 'cabal unpack' command as in #390
Andrea Vezzosi <sanzhiyan@gmail.com>**20081113185923] 
[Remove use of tabs
Duncan Coutts <duncan@haskell.org>**20081122163527] 
[Put explicit lower bound on version of base
Duncan Coutts <duncan@haskell.org>**20081122163151
 It does not build with ghc-6.4.2, missing Functor instance for Either.
] 
[Use a more general fix for "cabal install base"
Duncan Coutts <duncan@haskell.org>**20081122163026
 It's not specific to LHC. Normally we prevent upgrading of base
 since it's unlikely to work and would normally be accidental.
 However when the user explicitly asks to upgrade base then we
 let them do that and they can keep the pieces when it breaks.
] 
[Warn about use of tabs
Duncan Coutts <duncan@haskell.org>**20081122154309] 
[Only send the base file name when uploading tarballs
Duncan Coutts <duncan@haskell.org>**20080903230334
 The server should ignore the dir part anyway but there's no
 need to send it in the first place.
] 
[Slightly better lhc support.
Lemmih <lemmih@gmail.com>**20081121034338
 Ignore-this: 9f51f465aa87d1c6677ca492f877ecd6
] 
[TAG 0.6.0
Duncan Coutts <duncan@haskell.org>**20081011195420] 
[Bump version to 0.6.0
Duncan Coutts <duncan@haskell.org>**20081011195314] 
[Improve the README, better install instructions
Duncan Coutts <duncan@haskell.org>**20081011185919
 And slightly better intro guide to the main commands.
] 
[Bump versions of deps in the bootstrap script
Duncan Coutts <duncan@haskell.org>**20081011184937] 
[Add Eq for a couple types in the anon build reports
Duncan Coutts <duncan@haskell.org>**20081011184825] 
[Drop silly export
Duncan Coutts <duncan@haskell.org>**20081011184805] 
[Apparnetly builds with unix-2.0 which is what came with ghc-6.6
Duncan Coutts <duncan@haskell.org>**20081010234836] 
[Fix the -i dir for compiling Setup.hs when it's the current dir
Duncan Coutts <duncan@haskell.org>**20081010234558
 map "" to "."
] 
[Tidy up the preferred-versions file parser
Duncan Coutts <duncan@haskell.org>**20081010070105] 
[Bump version number and dependencies
Duncan Coutts <duncan@haskell.org>**20081010065854] 
[Relax deps to build with ghc-6.10
Duncan Coutts <duncan@haskell.org>**20081007230701] 
[Handle build reports with missing logs better
Duncan Coutts <duncan@haskell.org>**20081007230635] 
[Add DownloadFailed as a possible failure for installation
Duncan Coutts <duncan@haskell.org>**20081007230418
 Should now be caught during installing a bunch of packages
 and not cause immediate overall failure. It should instead
 be treated like any other package build failure and be
 reported at the end and only affect other dependent builds.
] 
[Fix search paths for compiling Setup.hs scrips
Duncan Coutts <duncan@haskell.org>**20081007213630
 and in particular for bootstrapping the Cabal lib.
] 
[Fix selecting paired packages
Duncan Coutts <duncan@haskell.org>**20081007062930
 Previously when we selected base 4 (and as a consequence
 slected base 3 too) we didn't properly trace the dependencies
 of base 3 so if nothing actually required base 3 then we ended
 up with base 3 in the solution but not with syb which it
 depends on. Consequently the solution was invalid.
 Now we select the paired package properly (hopefully).
] 
[Take preferred versions into account in dependency planning
Duncan Coutts <duncan@haskell.org>**20081006055129
 This means we can now globally prefer base 3 rather than 4.
 However we need to be slightly careful or we end up deciding
 to do silly things like rebuild haskell98 against base 3.
 That would happen because the h98 package doesn't constrain
 the choice to one or the other and we would prefer base 3.
 So we have to add that we really prefer whatever it uses
 currently (if any).
] 
[Pass the package suggested version constraints through to the resolver
Duncan Coutts <duncan@haskell.org>**20081006042758
 Not used yet.
] 
[Fix selection of paired packages
Duncan Coutts <duncan@haskell.org>**20081006040616] 
[Read preferred versions from the package index
Duncan Coutts <duncan@haskell.org>**20081006030259
 From a file named 'preferred-versions' in the 00-index.tar.gz
 If there are several they are combined. Contents is like:
 base < 4
 one suggested version constraint per line.
] 
[Refactor and update the hackage index reading code
Duncan Coutts <duncan@haskell.org>**20081005202747] 
[Print more details about what is to be installed with -v
Duncan Coutts <duncan@haskell.org>**20081005075556
 Reports if installs are new or reinstalls and for reinstalls
 prints what dependencies have changed.
] 
[When finalising paired packages, cope with there being multiple choices
Duncan Coutts <duncan@haskell.org>**20081005053821
 For ordinary packages we selected a single version which means
  we added an equality constraint. As a consequence we used to
 assume there was only one version left when finalising. For
 paired packages there may be two versions left if the package
 did not directly constrain the choice to just one. If there is
 more than one version remaining then we have to pick between
 them. At the moment we still pick the highest version, but
 later we can take a global preference or polciy into account.
] 
[When selecting paired packages, select both.
Duncan Coutts <duncan@haskell.org>**20081005053804] 
[Handle constraints on paired packages
Duncan Coutts <duncan@haskell.org>**20081005051919
 The trick is that when applying constraints to paired
 packages, the constraint has to exclude both packages at
 once. We exclude the pair together or not at all. If it
 would only exclude one then we discard the constraint.
] 
[Add the notion of paired packages to the Constraints ADT
Duncan Coutts <duncan@haskell.org>**20081005013141
 Packages like base-3 and base-4 are paired. This means they are
 supposed to be treated equivalently in some contexts. Paired
 packages are installed packages with the same name where one
 version depends on the other.
] 
[Make InstalledPackage an instance of PackageFixedDeps
Duncan Coutts <duncan@haskell.org>**20081005012741] 
[Add the glue code to actully report excluded packages
Duncan Coutts <duncan@haskell.org>**20081005001400
 Now displayed in the output of install --dry-run -v
] 
[Have Constraints.constrain report the excluded packages
Duncan Coutts <duncan@haskell.org>**20081004235006
 Each time we apply a constraint we can end up excluding some
 extra package. Report that list of packages because it is
 quite interesting information to get insight into what the
 resolver is actually doing.
] 
[Separate the construction of the exclusion list from its use
Duncan Coutts <duncan@haskell.org>**20081004234421
 Previously directly inserted packages into the excluded package
 list. Now we generate a list of them and then add them. We want
 the list of newly excluded packages separately because it is
 interesting information to report to the user when -v is on.
] 
[Generalise the logging of selected and discarded packages
Duncan Coutts <duncan@haskell.org>**20081004232555
 Allow for selecting several packages in one go.
 Currently when we select a package we only list the over versions
 of the same package that that excludes, and not the other packages
 we exclude by applying the dependency constraints of the selected
 package. In future we would like to do that so we now report the
 package name of discards not just the version. Though we do group
 by the package name to avoid too much repition.
] 
[Fix infinite loop in the TopDown dependency resolver
Andrea Vezzosi <sanzhiyan@gmail.com>**20080925181441
 The loop occurred only if a package depended on another one
 with the same name, e.g. base-3.0.3.0 <- base-4.0.0.0
] 
[small improvements to bootstrap
Duncan Coutts <duncan@haskell.org>**20080926214828
 patch sent in by brian0, ticket #357
] 
[Update to the development version of the Cabal lib
Duncan Coutts <duncan@haskell.org>**20080831225243
 The branch of cabal-install that tracks Cabal-1.4 now lives at
 http://darcs.haskell.org/cabal-branches/cabal-install-0.5/
] 
[Allow use of curl in bootstrap.sh
Duncan Coutts <duncan@haskell.org>**20080826233400
 Patch from jsnx. Fixes ticket #343. Also, use "cd blah; cd .."
 instead of "pushd blah; popd" as some shells lack pushd/popd
] 
[Relax version constraint on unix package
Duncan Coutts <duncan@haskell.org>**20080826232851
 Allows building with ghc-6.6.1
] 
[Use mplus not mappend for combining tar filename checks
Duncan Coutts <duncan@haskell.org>**20080826232606
 mappend would join the error messages in the case that both
 checks failed. Also the monoid instance was new in base 3.
] 
[TAG 0.5.2
Duncan Coutts <duncan@haskell.org>**20080826214238] 
Patch bundle hash:
d3ff023708178ec167f7752a57b39d8a6f676f54