path: root/src/Propellor/Types/Core.hs
diff options
authorJoey Hess2018-04-23 13:20:13 -0400
committerJoey Hess2018-04-23 13:20:13 -0400
commit9228bda32f0a3f6d52e7cc5eb444376e7b024d8c (patch)
treee3ada017b0f625db8b39a2212ab82c8e32a62b7c /src/Propellor/Types/Core.hs
parent5ecbec11127449fefe4812fd6b374801ce8499c1 (diff)
semigroup monoid change fallout; drop ghc 7 support
Fix build with ghc 8.4, which broke due to the Semigroup Monoid change. See Dropped support for building propellor with ghc 7 (as in debian oldstable), to avoid needing to depend on the semigroups transitional package, but also because it's just too old to be worth supporting. If we indeed drop ghc 7 support entirely, some code to support "jessie" can be removed; concurrent-output can be de-embedded, and the Singletons code can be simplified. This commit was sponsored by Jack Hill on Patreon.
Diffstat (limited to 'src/Propellor/Types/Core.hs')
1 files changed, 7 insertions, 3 deletions
diff --git a/src/Propellor/Types/Core.hs b/src/Propellor/Types/Core.hs
index a805f561..cd3e09c5 100644
--- a/src/Propellor/Types/Core.hs
+++ b/src/Propellor/Types/Core.hs
@@ -10,6 +10,7 @@ import Propellor.Types.OS
import Propellor.Types.Result
import Data.Monoid
+import qualified Data.Semigroup as Sem
import "mtl" Control.Monad.RWS.Strict
import Control.Monad.Catch
import Control.Applicative
@@ -50,15 +51,18 @@ instance LiftPropellor IO where
-- | When two actions are appended together, the second action
-- is only run if the first action does not fail.
-instance Monoid (Propellor Result) where
- mempty = return NoChange
- mappend x y = do
+instance Sem.Semigroup (Propellor Result) where
+ x <> y = do
rx <- x
case rx of
FailedChange -> return FailedChange
_ -> do
ry <- y
return (rx <> ry)
+instance Monoid (Propellor Result) where
+ mempty = return NoChange
+ mappend = (<>)
-- | An action that Propellor runs at the end, after trying to satisfy all
-- properties. It's passed the combined Result of the entire Propellor run.