Add a --no-run flag to the script command

Author: snoyberg

ChangeLog.md

@@ -13,6 +13,8 @@ Behavior changes:
 
 Other enhancements:
 
+* Add a `--no-run` flag to the `script` command when compiling.
+
 Bug fixes:
 
 * GHC source builds work properly for recent GHC versions again. See

src/Stack/Options/ScriptParser.hs

@@ -13,6 +13,7 @@ data ScriptOpts = ScriptOpts
   , soCompile :: !ScriptExecute
   , soGhcOptions :: ![String]
   , soScriptExtraDeps :: ![PackageIdentifierRevision]
+  , soShouldRun :: !ShouldRun
   }
   deriving Show
 
@@ -22,6 +23,9 @@ data ScriptExecute
   | SEOptimize
   deriving Show
 
+data ShouldRun = YesRun | NoRun
+  deriving Show
+
 scriptOptsParser :: Parser ScriptOpts
 scriptOptsParser = ScriptOpts
     <$> many (strOption
@@ -48,5 +52,6 @@ scriptOptsParser = ScriptOpts
           (long "extra-dep" <>
             metavar "PACKAGE-VERSION" <>
             help "Extra dependencies to be added to the snapshot"))
+    <*> (flag' NoRun (long "no-run" <> help "Don't run, just compile.") <|> pure YesRun)
   where
     extraDepRead = eitherReader $ mapLeft show . parsePackageIdentifierRevision . fromString

src/Stack/Script.hs

@@ -84,6 +84,15 @@ scriptCmd opts = do
             , globalStackYaml = SYLNoProject $ soScriptExtraDeps opts
             }
 
+    case soShouldRun opts of
+      YesRun -> pure ()
+      NoRun -> do
+        unless (null $ soArgs opts) $ throwString "--no-run incompatible with arguments"
+        case soCompile opts of
+          SEInterpret -> throwString "--no-run requires either --compile or --optimize"
+          SECompile -> pure ()
+          SEOptimize -> pure ()
+
     -- Optimization: if we're compiling, and the executable is newer
     -- than the source file, run it immediately.
     local (over globalOptsL modifyGO) $
@@ -93,11 +102,16 @@ scriptCmd opts = do
         SEOptimize -> shortCut file scriptDir
 
   where
+  runCompiled file = do
+    let exeName = toExeName $ toFilePath file
+    case soShouldRun opts of
+      YesRun -> exec exeName (soArgs opts)
+      NoRun -> logInfo $ "Compilation finished, executable available at " <> fromString exeName
   shortCut file scriptDir = handleIO (const $ longWay file scriptDir) $ do
     srcMod <- getModificationTime file
     exeMod <- Dir.getModificationTime $ toExeName $ toFilePath file
     if srcMod < exeMod
-      then exec (toExeName $ toFilePath file) (soArgs opts)
+      then runCompiled file
       else longWay file scriptDir
 
   longWay file scriptDir =
@@ -168,7 +182,7 @@ scriptCmd opts = do
               compilerExeName
               (ghcArgs ++ [toFilePath file])
               (void . readProcessStdout_)
-            exec (toExeName $ toFilePath file) (soArgs opts)
+            runCompiled file
 
   toPackageName = reverse . drop 1 . dropWhile (/= '-') . reverse