Add log message for missing cabal-fmt executable

Author: fendor

plugins/hls-cabal-fmt-plugin/src/Ide/Plugin/CabalFmt.hs

@@ -21,6 +21,7 @@ data Log
 =LogProcessInvocationFailureInt
  | LogReadCreateProcessInfoString [String]
  | LogInvalidInvocationInfo
+ | LogCabalFmtNotFound
 deriving (Show)
 
 instancePrettyLogwhere
@@ -31,6 +32,7 @@ instance Pretty Log where
  ["Invocation of cabal-fmt with arguments"<+> pretty args]
 ++ ["failed with standard error:"<+> pretty stdErrorOut |not (null stdErrorOut)]
 LogInvalidInvocationInfo->"Invocation of cabal-fmt with range was called but is not supported."
+LogCabalFmtNotFound->"Couldn't find executable 'cabal-fmt'"
 
 descriptor::Recorder (WithPriorityLog) ->PluginId->PluginDescriptorIdeState
 descriptor recorder plId =
@@ -66,6 +68,7 @@ provider recorder _ide FormatText contents nfp opts = liftIO $ do
 let fmtDiff = makeDiffTextEdit contents (T.pack out)
 pure$Right fmtDiff
 Nothing->do
+logErrorLogCabalFmtNotFound
 pure$Left (ResponseErrorInvalidRequest"No installation of cabal-fmt could be found. Please install it into your global environment."Nothing)
 where
  fp = fromNormalizedFilePath nfp