deepseq all things returned from ResourceT http

Potentially fixes https://git-annex.branchable.com/bugs/concurrent_git-annex-copy_to_s3_special_remote_fails/
although I don't know if it does.

My thinking is, ResourceT may allocate a resource and then free it,
and a unforced thunk to that resource could result in reading memory
that has since been overwritten by something else, or in a SEGV,
depending. While that seems kind of like a bug in ResourceT to me, if it
is what's happening, this will avoid it. If it's not, this doesn't
really hurt much since the values are all smallish.

This commit was sponsored by Graham Spencer on Patreon.

Types/Export.hs

@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE DeriveGeneric #-}
+
 module Types.Export (
 	ExportLocation,
 	mkExportLocation,
@@ -20,12 +22,16 @@ import Utility.Split
 import Utility.FileSystemEncoding
 
 import qualified System.FilePath.Posix as Posix
+import GHC.Generics
+import Control.DeepSeq
 
 -- A location on a remote that a key can be exported to.
 -- The RawFilePath will be relative to the top of the remote,
 -- and uses unix-style path separators.
 newtype ExportLocation = ExportLocation RawFilePath
-	deriving (Show, Eq)
+	deriving (Show, Eq, Generic)
+
+instance NFData ExportLocation
 
 mkExportLocation :: RawFilePath -> ExportLocation
 mkExportLocation = ExportLocation . toInternalGitPath

Types/Import.hs

@@ -5,10 +5,14 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE DeriveGeneric #-}
+
 module Types.Import where
 
 import qualified Data.ByteString as S
 import Data.Char
+import Control.DeepSeq
+import GHC.Generics
 
 import Types.Export
 import Utility.QuickCheck
@@ -29,7 +33,9 @@ fromImportLocation = fromExportLocation
  - the repository. It should be reasonably short since it is stored in the
  - git-annex branch. -}
 newtype ContentIdentifier = ContentIdentifier S.ByteString
-	deriving (Eq, Ord, Show)
+	deriving (Eq, Ord, Show, Generic)
+
+instance NFData ContentIdentifier
 
 instance Arbitrary ContentIdentifier where
 	-- Avoid non-ascii ContentIdentifiers because fully arbitrary
@@ -47,4 +53,6 @@ data ImportableContents info = ImportableContents
 	-- files that are stored in them. This is equivilant to a git
 	-- commit history.
 	}
-	deriving (Show)
+	deriving (Show, Generic)
+
+instance NFData info => NFData (ImportableContents info)