Don't build stack dependencies by default

Adds a global option `--stack-build-deps` to enable old behavior

Language/Haskell/GhcMod/CabalHelper.hs

@@ -208,7 +208,7 @@ withCabal action = do
                 -- "--flag PACKAGE:[-]FLAG Override flags set in stack.yaml
                 -- (applies to local packages and extra-deps)"
 
-                stackReconfigure crdl (optPrograms opts)
+                stackReconfigure (optStackBuildDeps opts) crdl (optPrograms opts)
             _ ->
                 error $ "withCabal: unsupported project type: " ++ show proj
 
@@ -234,12 +234,13 @@ withCabal action = do
             flagOpt = ["--flags", unwords $ map toFlag flgs]
 
         liftIO $ void $ readProc (T.cabalProgram progs) ("configure":progOpts) ""
-   stackReconfigure crdl progs = do
+   stackReconfigure deps crdl progs = do
      withDirectory_ (cradleRootDir crdl) $ do
        supported <- haveStackSupport
        if supported
           then do
-            spawn [T.stackProgram progs, "build", "--only-dependencies", "."]
+            when deps $
+              spawn [T.stackProgram progs, "build", "--only-dependencies", "."]
             spawn [T.stackProgram progs, "build", "--only-configure", "."]
           else
             gmLog GmWarning "" $ strDoc $ "Stack project configuration is out of date, please reconfigure manually using 'stack build' as your stack version is too old (need at least 0.1.4.0)"

Language/Haskell/GhcMod/Options/Options.hs

@@ -146,6 +146,10 @@ globalArgSpec = Options
           <=> value "UTF-8"
           <=> showDefault
           <=> help "I/O encoding"
+      <*> switch
+          $$  long "stack-build-deps"
+          <=> showDefault
+          <=> help "Build dependencies if needed when using stack"
   where
     fileMappingSpec =
       getFileMapping . splitOn '=' <$> strOption

Language/Haskell/GhcMod/Types.hs

@@ -106,6 +106,7 @@ data Options = Options {
   , optGhcUserOptions :: [GHCOption]
   , optFileMappings   :: [(FilePath, Maybe FilePath)]
   , optEncoding       :: String
+  , optStackBuildDeps :: Bool
   } deriving (Show)
 
 -- | A default 'Options'.
@@ -126,6 +127,7 @@ defaultOptions = Options {
   , optGhcUserOptions = []
   , optFileMappings   = []
   , optEncoding       = "UTF-8"
+  , optStackBuildDeps = False
   }
 
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