From b402dc87136700be1c231954366c42b67133eaa4 Mon Sep 17 00:00:00 2001
From: Mikhail Glushenkov <mikhail.glushenkov@gmail.com>
Date: Sat, 20 Feb 2016 17:31:07 +0100
Subject: [PATCH] Support full 'allow-newer' syntax in the config file.

---
 Cabal/Distribution/Simple/Setup.hs          | 14 ++++++--------
 Cabal/doc/installing-packages.markdown      |  3 ++-
 cabal-install/Distribution/Client/Config.hs |  7 ++++---
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Cabal/Distribution/Simple/Setup.hs b/Cabal/Distribution/Simple/Setup.hs
index 0556a708318..f9ef3244c67 100644
--- a/Cabal/Distribution/Simple/Setup.hs
+++ b/Cabal/Distribution/Simple/Setup.hs
@@ -308,13 +308,9 @@ isAllowNewer AllowNewerNone     = False
 isAllowNewer (AllowNewerSome _) = True
 isAllowNewer AllowNewerAll      = True
 
-allowNewerParser :: ReadE (Maybe AllowNewer)
-allowNewerParser = ReadE $ \s ->
-  case readPToMaybe pkgsParser s of
-    Just pkgs -> Right . Just . 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 :: (Maybe AllowNewer) -> [Maybe String]
 allowNewerPrinter Nothing                      = []
@@ -687,7 +683,9 @@ configureOptions showOrParseArgs =
       ,option [] ["allow-newer"]
        ("Ignore upper bounds in all dependencies or DEPS")
        configAllowNewer (\v flags -> flags { configAllowNewer = v})
-       (optArg "DEPS" allowNewerParser (Just 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."
diff --git a/Cabal/doc/installing-packages.markdown b/Cabal/doc/installing-packages.markdown
index 75ee4a743c5..fbb995d31dc 100644
--- a/Cabal/doc/installing-packages.markdown
+++ b/Cabal/doc/installing-packages.markdown
@@ -1000,7 +1000,8 @@ be controlled with the following command line options.
     ~~~~~~~~~~~~~~~~
 
     Finally, one can enable `--allow-newer` permanently by setting `allow-newer:
-    True` in the `~/.cabal/config` file.
+    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.
diff --git a/cabal-install/Distribution/Client/Config.hs b/cabal-install/Distribution/Client/Config.hs
index 76dade22be1..ffbb18c34b0 100644
--- a/cabal-install/Distribution/Client/Config.hs
+++ b/cabal-install/Distribution/Client/Config.hs
@@ -76,7 +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
@@ -108,7 +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
@@ -677,7 +677,8 @@ configFieldDescriptions src =
             toAllowNewer True  = Just AllowNewerAll
             toAllowNewer False = Just AllowNewerNone
 
-            parseAllowNewer = toAllowNewer `fmap` Text.parse in
+            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 })