Allow limiting the scope of '--allow-newer'.

Cabal/Distribution/Simple/Configure.hs

@@ -98,7 +98,7 @@ import qualified Data.ByteString.Lazy.Char8 as BLC8
 import Data.List
     ( (\\), nub, partition, isPrefixOf, inits, stripPrefix )
 import Data.Maybe
-    ( isNothing, catMaybes, fromMaybe, isJust )
+    ( isNothing, catMaybes, fromMaybe, mapMaybe, isJust )
 import Data.Either
     ( partitionEithers )
 import qualified Data.Set as Set
@@ -315,7 +315,9 @@ configure (pkg_descr0', pbi) cfg = do
           -- Ignore '--allow-newer' when we're given '--exact-configuration'.
           if fromFlagOrDefault False (configExactConfiguration cfg)
           then pkg_descr0'
-          else relaxPackageDeps (configAllowNewer cfg) pkg_descr0'
+          else relaxPackageDeps
+               (fromMaybe AllowNewerNone $ configAllowNewer cfg)
+               pkg_descr0'
 
     setupMessage verbosity "Configuring" (packageId pkg_descr0)
 
@@ -794,18 +796,28 @@ dependencySatisfiable
         isInternalDep = not . null
                       $ PackageIndex.lookupDependency internalPackageSet d
 
--- | Relax the dependencies of this package if needed
+-- | Relax the dependencies of this package if needed.
 relaxPackageDeps :: AllowNewer -> GenericPackageDescription
                  -> GenericPackageDescription
-relaxPackageDeps AllowNewerNone = id
-relaxPackageDeps AllowNewerAll  =
-  transformAllBuildDepends $ \(Dependency pkgName verRange) ->
-  Dependency pkgName (removeUpperBound verRange)
-relaxPackageDeps (AllowNewerSome pkgNames) =
-  transformAllBuildDepends $ \d@(Dependency pkgName verRange) ->
-  if pkgName `elem` pkgNames
-  then Dependency pkgName (removeUpperBound verRange)
-  else d
+relaxPackageDeps AllowNewerNone gpd = gpd
+relaxPackageDeps AllowNewerAll  gpd = transformAllBuildDepends relaxAll gpd
+  where
+    relaxAll = \(Dependency pkgName verRange) ->
+      Dependency pkgName (removeUpperBound verRange)
+relaxPackageDeps (AllowNewerSome allowNewerDeps') gpd =
+  transformAllBuildDepends relaxSome gpd
+  where
+    thisPkgName    = packageName gpd
+    allowNewerDeps = mapMaybe f allowNewerDeps'
+
+    f (Setup.AllowNewerDep p) = Just p
+    f (Setup.AllowNewerDepScoped scope p) | scope == thisPkgName = Just p
+                                          | otherwise            = Nothing
+
+    relaxSome = \d@(Dependency depName verRange) ->
+      if depName `elem` allowNewerDeps
+      then Dependency depName (removeUpperBound verRange)
+      else d
 
 -- | Finalize a generic package description.  The workhorse is
 -- 'finalizePackageDescription' but there's a bit of other nattering

Cabal/Distribution/Simple/Setup.hs

@@ -34,7 +34,7 @@ module Distribution.Simple.Setup (
 
   GlobalFlags(..),   emptyGlobalFlags,   defaultGlobalFlags,   globalCommand,
   ConfigFlags(..),   emptyConfigFlags,   defaultConfigFlags,   configureCommand,
-  AllowNewer(..),    isAllowNewer,
+  AllowNewer(..),    AllowNewerDep(..),  isAllowNewer,
   configAbsolutePaths, readPackageDbList, showPackageDbList,
   CopyFlags(..),     emptyCopyFlags,     defaultCopyFlags,     copyCommand,
   InstallFlags(..),  emptyInstallFlags,  defaultInstallFlags,  installCommand,
@@ -86,11 +86,12 @@ import Distribution.Utils.NubList
 import Distribution.Compat.Binary (Binary)
 import Distribution.Compat.Semigroup as Semi
 
-import Control.Monad (liftM)
-import Data.List   ( sort )
-import Data.Maybe  ( listToMaybe )
-import Data.Char   ( isSpace, isAlpha )
-import GHC.Generics (Generic)
+import Control.Applicative as A ( Applicative(..), (<*) )
+import Control.Monad            ( liftM )
+import Data.List                ( sort )
+import Data.Maybe               ( listToMaybe )
+import Data.Char                ( isSpace, isAlpha )
+import GHC.Generics             ( Generic )
 
 -- FIXME Not sure where this should live
 defaultDistPref :: FilePath
@@ -266,13 +267,29 @@ data AllowNewer =
   AllowNewerNone
 
   -- | Ignore upper bounds in dependencies on the given packages.
-  | AllowNewerSome [PackageName]
+  | AllowNewerSome [AllowNewerDep]
 
   -- | Ignore upper bounds in dependencies on all packages.
   | AllowNewerAll
-  deriving (Eq, Ord, Read, Show, Generic)
+  deriving (Read, Show, Generic)
+
+-- | Dependencies can be relaxed either for all packages in the install plan, or
+-- only for some packages.
+data AllowNewerDep = AllowNewerDep PackageName
+                   | AllowNewerDepScoped PackageName PackageName
+                   deriving (Read, Show, Generic)
+
+instance Text AllowNewerDep where
+  disp (AllowNewerDep p0)          = disp p0
+  disp (AllowNewerDepScoped p0 p1) = disp p0 Disp.<> Disp.colon Disp.<> disp p1
+
+  parse = scopedP Parse.<++ normalP
+    where
+      scopedP = AllowNewerDepScoped `fmap` parse A.<* Parse.char ':' A.<*> parse
+      normalP = AllowNewerDep       `fmap` parse
 
 instance Binary AllowNewer
+instance Binary AllowNewerDep
 
 instance Semigroup AllowNewer where
   AllowNewerNone       <> r                    = r
@@ -291,19 +308,15 @@ isAllowNewer AllowNewerNone     = False
 isAllowNewer (AllowNewerSome _) = True
 isAllowNewer AllowNewerAll      = True
 
-allowNewerParser :: ReadE AllowNewer
-allowNewerParser = ReadE $ \s ->
-  case readPToMaybe pkgsParser s of
-    Just pkgs -> Right . AllowNewerSome $ pkgs
-    Nothing   -> Left ("Cannot parse the list of packages: " ++ s)
-  where
-    pkgsParser = Parse.sepBy1 parse (Parse.char ',')
+allowNewerParser :: Parse.ReadP r (Maybe AllowNewer)
+allowNewerParser =
+  (Just . AllowNewerSome) `fmap` Parse.sepBy1 parse (Parse.char ',')
 
-allowNewerPrinter :: AllowNewer -> [Maybe String]
-allowNewerPrinter AllowNewerNone        = []
-allowNewerPrinter AllowNewerAll         = [Nothing]
-allowNewerPrinter (AllowNewerSome pkgs) =
-  [Just . intercalate "," . map display $ pkgs]
+allowNewerPrinter :: (Maybe AllowNewer) -> [Maybe String]
+allowNewerPrinter Nothing                      = []
+allowNewerPrinter (Just AllowNewerNone)        = []
+allowNewerPrinter (Just AllowNewerAll)         = [Nothing]
+allowNewerPrinter (Just (AllowNewerSome pkgs)) = map (Just . display) $ pkgs
 
 -- | Flags to @configure@ command.
 --
@@ -375,8 +388,9 @@ data ConfigFlags = ConfigFlags {
       -- ^Halt and show an error message indicating an error in flag assignment
     configRelocatable :: Flag Bool, -- ^ Enable relocatable package built
     configDebugInfo :: Flag DebugInfoLevel,  -- ^ Emit debug info.
-    configAllowNewer :: AllowNewer      -- ^ Ignore upper bounds on all or some
-                                        -- dependencies.
+    configAllowNewer :: Maybe AllowNewer
+    -- ^ Ignore upper bounds on all or some dependencies. Wrapped in 'Maybe' to
+    -- distinguish between "default" and "explicitly disabled".
   }
   deriving (Generic, Read, Show)
 
@@ -423,7 +437,7 @@ defaultConfigFlags progConf = emptyConfigFlags {
     configFlagError    = NoFlag,
     configRelocatable  = Flag False,
     configDebugInfo    = Flag NoDebugInfo,
-    configAllowNewer   = AllowNewerNone
+    configAllowNewer   = Nothing
   }
 
 configureCommand :: ProgramConfiguration -> CommandUI ConfigFlags
@@ -669,7 +683,9 @@ configureOptions showOrParseArgs =
       ,option [] ["allow-newer"]
        ("Ignore upper bounds in all dependencies or DEPS")
        configAllowNewer (\v flags -> flags { configAllowNewer = v})
-       (optArg "DEPS" allowNewerParser AllowNewerAll allowNewerPrinter)
+       (optArg "DEPS"
+        (readP_to_E ("Cannot parse the list of packages: " ++) allowNewerParser)
+        (Just AllowNewerAll) allowNewerPrinter)
 
       ,option "" ["exact-configuration"]
          "All direct dependencies and flags are provided on the command line."

Cabal/doc/installing-packages.markdown

@@ -982,8 +982,26 @@ be controlled with the following command line options.
     $ cabal install --allow-newer=bar --constraint="bar==2.1" foo
     ~~~~~~~~~~~~~~~~
 
-    It's also possible to enable `--allow-newer` permanently by setting
-    `allow-newer: True` in the `~/.cabal/config` file.
+    It's also possible to limit the scope of `--allow-newer` to single
+    packages with the `--allow-newer=scope:dep` syntax. This means that the
+    dependency on `dep` will be relaxed only for the package `scope`.
+
+    Example:
+
+    ~~~~~~~~~~~~~~~~
+    # Relax upper bound in foo's dependency on base; also relax upper bound in
+    # every package's dependency on lens.
+    $ cabal install --allow-newer=foo:base,lens
+
+    # Relax upper bounds in foo's dependency on base and bar's dependency
+    # on time; also relax the upper bound in the dependency on lens specified by
+    # any package.
+    $ cabal install --allow-newer=foo:base,lens --allow-newer=bar:time
+    ~~~~~~~~~~~~~~~~
+
+    Finally, one can enable `--allow-newer` permanently by setting `allow-newer:
+    True` in the `~/.cabal/config` file. Enabling 'allow-newer' selectively is
+    also supported in the config file (`allow-newer: foo, bar, baz:base`).
 
 `--constraint=`_constraint_
 :   Restrict solutions involving a package to a given version range.

Cabal/tests/PackageTests/Tests.hs

@@ -236,6 +236,15 @@ nonSharedLibTests config =
         shouldFail $ cabal "configure" ["--enable-benchmarks", "--enable-tests"]
         cabal "configure" ["--enable-benchmarks", "--enable-tests"
                           ,"--allow-newer"]
+        shouldFail $ cabal "configure" ["--allow-newer=Foo:base"]
+        shouldFail $ cabal "configure" ["--allow-newer=Foo:base"
+                                       ,"--enable-tests", "--enable-benchmarks"]
+        cabal "configure" ["--allow-newer=AllowNewer:base"]
+        cabal "configure" ["--allow-newer=AllowNewer:base"
+                          ,"--allow-newer=Foo:base"]
+        cabal "configure" ["--allow-newer=AllowNewer:base"
+                          ,"--allow-newer=Foo:base"
+                          ,"--enable-tests", "--enable-benchmarks"]
 
   -- Test that Cabal can choose flags to disable building a component when that
   -- component's dependencies are unavailable. The build should succeed without

cabal-install/Distribution/Client/Config.hs

@@ -62,6 +62,7 @@ import Distribution.Simple.Compiler
          ( DebugInfoLevel(..), OptimisationLevel(..) )
 import Distribution.Simple.Setup
          ( ConfigFlags(..), configureOptions, defaultConfigFlags
+         , AllowNewer(..)
          , HaddockFlags(..), haddockOptions, defaultHaddockFlags
          , installDirsOptions, optionDistPref
          , programConfigurationPaths', programConfigurationOptions
@@ -75,7 +76,7 @@ import Distribution.ParseUtils
          , locatedErrorMsg, showPWarning
          , readFields, warning, lineNo
          , simpleField, listField, spaceListField
-         , parseFilePathQ, parseTokenQ )
+         , parseFilePathQ, parseOptCommaList, parseTokenQ )
 import Distribution.Client.ParseUtils
          ( parseFields, ppFields, ppSection )
 import Distribution.Client.HttpUtils
@@ -107,7 +108,7 @@ import Data.Monoid
 import Control.Monad
          ( when, unless, foldM, liftM, liftM2 )
 import qualified Distribution.Compat.ReadP as Parse
-         ( option )
+         ( (<++), option )
 import Distribution.Compat.Semigroup
          ( Semigroup((<>)) )
 import qualified Text.PrettyPrint as Disp
@@ -639,7 +640,8 @@ commentSavedConfig = do
     savedInstallFlags      = defaultInstallFlags,
     savedConfigureExFlags  = defaultConfigExFlags,
     savedConfigureFlags    = (defaultConfigFlags defaultProgramConfiguration) {
-      configUserInstall    = toFlag defaultUserInstall
+      configUserInstall    = toFlag defaultUserInstall,
+      configAllowNewer     = Just AllowNewerNone
     },
     savedUserInstallDirs   = fmap toFlag userInstallDirs,
     savedGlobalInstallDirs = fmap toFlag globalInstallDirs,
@@ -668,6 +670,18 @@ configFieldDescriptions src =
        [simpleField "compiler"
           (fromFlagOrDefault Disp.empty . fmap Text.disp) (optional Text.parse)
           configHcFlavor (\v flags -> flags { configHcFlavor = v })
+       ,let showAllowNewer Nothing               = mempty
+            showAllowNewer (Just AllowNewerNone) = Disp.text "False"
+            showAllowNewer (Just _)              = Disp.text "True"
+
+            toAllowNewer True  = Just AllowNewerAll
+            toAllowNewer False = Just AllowNewerNone
+
+            pkgs = (Just . AllowNewerSome) `fmap` parseOptCommaList Text.parse
+            parseAllowNewer = (toAllowNewer `fmap` Text.parse) Parse.<++ pkgs in
+        simpleField "allow-newer"
+        showAllowNewer parseAllowNewer
+        configAllowNewer (\v flags -> flags { configAllowNewer = v })
         -- TODO: The following is a temporary fix. The "optimization"
         -- and "debug-info" fields are OptArg, and viewAsFieldDescr
         -- fails on that. Instead of a hand-written hackaged parser

cabal-install/Distribution/Client/Configure.hs

@@ -43,7 +43,8 @@ import Distribution.Simple.Compiler
          ( Compiler, CompilerInfo, compilerInfo, PackageDB(..), PackageDBStack )
 import Distribution.Simple.Program (ProgramConfiguration )
 import Distribution.Simple.Setup
-         ( ConfigFlags(..), fromFlag, toFlag, flagToMaybe, fromFlagOrDefault )
+         ( ConfigFlags(..), AllowNewer(..)
+         , fromFlag, toFlag, flagToMaybe, fromFlagOrDefault )
 import Distribution.Simple.PackageIndex
          ( InstalledPackageIndex, lookupPackageName )
 import Distribution.Simple.Utils
@@ -86,7 +87,8 @@ chooseCabalVersion configFlags maybeVersion =
   where
     -- Cabal < 1.19.2 doesn't support '--exact-configuration' which is needed
     -- for '--allow-newer' to work.
-    allowNewer = isAllowNewer (configAllowNewer configFlags)
+    allowNewer = isAllowNewer
+                 (fromMaybe AllowNewerNone $ configAllowNewer configFlags)
 
     defaultVersionRange = if allowNewer
                           then orLaterVersion (Version [1,19,2] [])
@@ -288,7 +290,8 @@ planLocalPackage verbosity comp platform configFlags configExFlags
         fromFlagOrDefault False $ configBenchmarks configFlags
 
       resolverParams =
-          removeUpperBounds (configAllowNewer configFlags)
+          removeUpperBounds
+          (fromMaybe AllowNewerNone $ configAllowNewer configFlags)
 
         . addPreferences
             -- preferences from the config file or command line

cabal-install/Distribution/Client/Install.hs

@@ -124,6 +124,7 @@ import qualified Distribution.Simple.Configure as Configure
 import Distribution.Simple.Setup
          ( haddockCommand, HaddockFlags(..)
          , buildCommand, BuildFlags(..), emptyBuildFlags
+         , AllowNewer(..)
          , toFlag, fromFlag, fromFlagOrDefault, flagToMaybe, defaultDistPref )
 import qualified Distribution.Simple.Setup as Cabal
          ( Flag(..)
@@ -417,7 +418,7 @@ planPackages comp platform mSandboxPkgInfo solver
     maxBackjumps     = fromFlag (installMaxBackjumps      installFlags)
     upgradeDeps      = fromFlag (installUpgradeDeps       installFlags)
     onlyDeps         = fromFlag (installOnlyDeps          installFlags)
-    allowNewer       = (configAllowNewer         configFlags)
+    allowNewer       = fromMaybe AllowNewerNone (configAllowNewer configFlags)
 
 -- | Remove the provided targets from the install plan.
 pruneInstallPlan :: Package targetpkg

cabal-install/Distribution/Client/Setup.hs

@@ -370,7 +370,7 @@ filterConfigureFlags flags cabalLibVersion
       configConstraints = [],
       -- Passing '--allow-newer' to Setup.hs is unnecessary, we use
       -- '--exact-configuration' instead.
-      configAllowNewer  = Cabal.AllowNewerNone
+      configAllowNewer  = Just Cabal.AllowNewerNone
       }
 
     -- Cabal < 1.23 doesn't know about '--profiling-detail'.

cabal-install/changelog

@@ -47,6 +47,10 @@
 	* New config file field: 'extra-framework-dirs' (extra locations
 	to find OS X frameworks in). Can be also specified as an argument
 	for 'install' and 'configure' commands (#3158).
+	* It's now possible to limit the scope of '--allow-newer' to
+	single packages in the install plan (#2756).
+	* Full '--allow-newer' syntax is now supported in the config file
+	(that is, 'allow-newer: base, ghc-prim,  some-package:vector') (#3171).
 
 1.22.0.0 Johan Tibell <johan.tibell@gmail.com> January 2015
 	* New command: user-config (#2159).