return (pkgs2, preload1, new_this_pkg)
--- -----------------------------------------------------------------------------
+-- ----------------------------------------------------------------------------
--
--- Eliminate any packages which have dangling dependencies (
--- because the dependency was removed by -ignore-package).
+-- Detect any packages that have missing dependencies, and also any
+-- mutually-recursive groups of packages (loops in the package graph
+-- are not allowed). We do this by taking the least fixpoint of the
+-- dependency graph, repeatedly adding packages whose dependencies are
+-- satisfied until no more can be added.
--
elimDanglingDeps
:: DynFlags
-> [PackageId] -- ignored packages
-> IO [PackageConfig]
-elimDanglingDeps dflags pkgs ignored =
- case partition (not.null.snd) (map (getDanglingDeps pkgs ignored) pkgs) of
- ([],ps) -> return (map fst ps)
- (ps,qs) -> do
- mapM_ reportElim ps
- elimDanglingDeps dflags (map fst qs)
- (ignored ++ map packageConfigId (map fst ps))
+elimDanglingDeps dflags pkgs ignored = go [] pkgs'
where
+ pkgs' = filter (\p -> packageConfigId p `notElem` ignored) pkgs
+
+ go avail not_avail =
+ case partitionWith (depsAvailable avail) not_avail of
+ ([], not_avail) -> do mapM_ reportElim not_avail; return avail
+ (new_avail, not_avail) -> go (new_avail ++ avail) (map fst not_avail)
+
+ depsAvailable :: [PackageConfig] -> PackageConfig
+ -> Either PackageConfig (PackageConfig, [PackageIdentifier])
+ depsAvailable pkgs_ok pkg
+ | null dangling = Left pkg
+ | otherwise = Right (pkg, dangling)
+ where dangling = filter (`notElem` pids) (depends pkg)
+ pids = map package pkgs_ok
+
reportElim (p, deps) =
debugTraceMsg dflags 2 $
(ptext SLIT("package") <+> pprPkg p <+>
- ptext SLIT("will be ignored due to missing dependencies:") $$
+ ptext SLIT("will be ignored due to missing or recursive dependencies:") $$
nest 2 (hsep (map (text.showPackageId) deps)))
- getDanglingDeps pkgs ignored p = (p, filter dangling (depends p))
- where dangling pid = mkPackageId pid `elem` ignored
-
-- -----------------------------------------------------------------------------
-- When all the command-line options are in, we can process our package
-- settings and populate the package state.