remote: add SuccessCodeReply

Add SuccessCodeReply to replace instances of the () reply type.

The serialization behavior is more clear with the more explicit type.

hnix-store-remote/hnix-store-remote.cabal

@@ -93,6 +93,7 @@ library
     , System.Nix.Store.Remote.Types.StoreReply
     , System.Nix.Store.Remote.Types.StoreText
     , System.Nix.Store.Remote.Types.SubstituteMode
+    , System.Nix.Store.Remote.Types.SuccessCodeReply
     , System.Nix.Store.Remote.Types.TrustedFlag
     , System.Nix.Store.Remote.Types.Verbosity
     , System.Nix.Store.Remote.Types.WorkerMagic

hnix-store-remote/src/System/Nix/Store/Remote/Client.hs

@@ -26,7 +26,7 @@ module System.Nix.Store.Remote.Client
   , module System.Nix.Store.Remote.Client.Core
   ) where
 
-import Control.Monad (when)
+import Control.Monad (void, when)
 import Control.Monad.Except (throwError)
 import Data.HashSet (HashSet)
 import Data.Map (Map)
@@ -96,7 +96,7 @@ addSignatures
   => StorePath
   -> Set Signature
   -> m ()
-addSignatures p signatures = doReq (AddSignatures p signatures)
+addSignatures p signatures = (void . doReq) (AddSignatures p signatures)
 
 -- | Add temporary garbage collector root.
 --
@@ -105,14 +105,14 @@ addTempRoot
   :: MonadRemoteStore m
   => StorePath
   -> m ()
-addTempRoot = doReq . AddTempRoot
+addTempRoot = void . doReq . AddTempRoot
 
 -- | Add indirect garbage collector root.
 addIndirectRoot
   :: MonadRemoteStore m
   => StorePath
   -> m ()
-addIndirectRoot = doReq . AddIndirectRoot
+addIndirectRoot = void . doReq . AddIndirectRoot
 
 -- | Build a derivation available at @StorePath@
 buildDerivation
@@ -139,7 +139,7 @@ buildPaths
   => Set DerivedPath
   -> BuildMode
   -> m ()
-buildPaths a b = doReq (BuildPaths a b)
+buildPaths a b = (void . doReq) (BuildPaths a b)
 
 collectGarbage
   :: MonadRemoteStore m
@@ -151,7 +151,7 @@ ensurePath
   :: MonadRemoteStore m
   => StorePath
   -> m ()
-ensurePath = doReq . EnsurePath
+ensurePath = void . doReq . EnsurePath
 
 -- | Find garbage collector roots.
 findRoots
@@ -235,12 +235,12 @@ queryMissing = doReq . QueryMissing
 optimiseStore
   :: MonadRemoteStore m
   => m ()
-optimiseStore = doReq OptimiseStore
+optimiseStore = (void . doReq) OptimiseStore
 
 syncWithGC
   :: MonadRemoteStore m
   => m ()
-syncWithGC = doReq SyncWithGC
+syncWithGC = (void . doReq) SyncWithGC
 
 verifyStore
   :: MonadRemoteStore m

hnix-store-remote/src/System/Nix/Store/Remote/Serializer.hs

@@ -1368,14 +1368,14 @@ mapPutER = mapErrorST ReplySError_PrimPut
 -- | Parse a bool returned at the end of simple operations.
 -- This is always 1 (@True@) so we assert that it really is so.
 -- Errors for these operations are indicated via @Logger_Error@.
-opSuccess :: NixSerializer r ReplySError ()
+opSuccess :: NixSerializer r ReplySError SuccessCodeReply
 opSuccess = Serializer
   { getS = do
       retCode <- mapGetER $ getS bool
       Control.Monad.unless
         (retCode == True)
         $ throwError ReplySError_UnexpectedFalseOpSuccess
-      pure ()
+      pure SuccessCodeReply
   , putS = \_ -> mapPutER $ putS bool True
   }
 

hnix-store-remote/src/System/Nix/Store/Remote/Types.hs

@@ -9,6 +9,7 @@ module System.Nix.Store.Remote.Types
   , module System.Nix.Store.Remote.Types.StoreRequest
   , module System.Nix.Store.Remote.Types.StoreText
   , module System.Nix.Store.Remote.Types.SubstituteMode
+  , module System.Nix.Store.Remote.Types.SuccessCodeReply
   , module System.Nix.Store.Remote.Types.TrustedFlag
   , module System.Nix.Store.Remote.Types.Verbosity
   , module System.Nix.Store.Remote.Types.WorkerMagic
@@ -25,6 +26,7 @@ import System.Nix.Store.Remote.Types.StoreConfig
 import System.Nix.Store.Remote.Types.StoreRequest
 import System.Nix.Store.Remote.Types.StoreText
 import System.Nix.Store.Remote.Types.SubstituteMode
+import System.Nix.Store.Remote.Types.SuccessCodeReply
 import System.Nix.Store.Remote.Types.TrustedFlag
 import System.Nix.Store.Remote.Types.Verbosity
 import System.Nix.Store.Remote.Types.WorkerMagic

hnix-store-remote/src/System/Nix/Store/Remote/Types/StoreReply.hs

@@ -8,6 +8,7 @@ import System.Nix.Build (BuildResult)
 import System.Nix.StorePath (StorePath, StorePathName)
 import System.Nix.StorePath.Metadata (Metadata)
 import System.Nix.Store.Remote.Serializer
+import System.Nix.Store.Remote.Types.SuccessCodeReply (SuccessCodeReply)
 import System.Nix.Store.Remote.Types.GC (GCResult, GCRoot)
 import System.Nix.Store.Remote.Types.Query.Missing (Missing)
 import System.Nix.Store.Remote.Types.StoreConfig (ProtoStoreConfig)
@@ -20,7 +21,7 @@ import System.Nix.Store.Remote.Types.StoreConfig (ProtoStoreConfig)
 class StoreReply a where
   getReplyS :: NixSerializer ProtoStoreConfig ReplySError a
 
-instance StoreReply () where
+instance StoreReply SuccessCodeReply where
   getReplyS = opSuccess
 
 instance StoreReply Bool where

hnix-store-remote/src/System/Nix/Store/Remote/Types/StoreRequest.hs

@@ -28,6 +28,7 @@ import System.Nix.Store.Remote.Types.CheckMode (CheckMode)
 import System.Nix.Store.Remote.Types.Query.Missing (Missing)
 import System.Nix.Store.Remote.Types.StoreText (StoreText)
 import System.Nix.Store.Remote.Types.SubstituteMode (SubstituteMode)
+import System.Nix.Store.Remote.Types.SuccessCodeReply (SuccessCodeReply)
 
 data StoreRequest :: Type -> Type where
   -- | Add @NarSource@ to the store.
@@ -51,18 +52,18 @@ data StoreRequest :: Type -> Type where
   AddSignatures
     :: StorePath
     -> Set Signature
-    -> StoreRequest ()
+    -> StoreRequest SuccessCodeReply
 
   AddIndirectRoot
     :: StorePath
-    -> StoreRequest ()
+    -> StoreRequest SuccessCodeReply
 
   -- | Add temporary garbage collector root.
   --
   -- This root is removed as soon as the client exits.
   AddTempRoot
     :: StorePath
-    -> StoreRequest ()
+    -> StoreRequest SuccessCodeReply
 
   -- | Build paths if they are an actual derivations.
   --
@@ -70,7 +71,7 @@ data StoreRequest :: Type -> Type where
   BuildPaths
     :: Set DerivedPath
     -> BuildMode
-    -> StoreRequest ()
+    -> StoreRequest SuccessCodeReply
 
   BuildDerivation
     :: StorePath
@@ -84,7 +85,7 @@ data StoreRequest :: Type -> Type where
 
   EnsurePath
     :: StorePath
-    -> StoreRequest ()
+    -> StoreRequest SuccessCodeReply
 
   -- | Find garbage collector roots.
   FindRoots
@@ -138,10 +139,10 @@ data StoreRequest :: Type -> Type where
     -> StoreRequest Missing
 
   OptimiseStore
-    :: StoreRequest ()
+    :: StoreRequest SuccessCodeReply
 
   SyncWithGC
-    :: StoreRequest ()
+    :: StoreRequest SuccessCodeReply
 
   -- returns True on errors
   VerifyStore

hnix-store-remote/src/System/Nix/Store/Remote/Types/SuccessCodeReply.hs

@@ -0,0 +1,8 @@
+module System.Nix.Store.Remote.Types.SuccessCodeReply
+  ( SuccessCodeReply(..)
+  ) where
+
+-- | Reply that checks an int success return value
+data SuccessCodeReply = SuccessCodeReply
+  deriving (Show)
+