Avoid writing a JS file when executing spago run (#846)

Author: sigma-andex

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+Other improvements:
+- Avoid writing a JS file when executing `spago run` (#845, #846)
+
 ## [0.20.4] - 2022-01-29
 
 Bugfixes:

src/Spago/Build.hs

@@ -330,29 +330,25 @@ runBackend maybeBackend RunDirectories{ sourceDir, executeDir } moduleName maybe
   build (Just postBuild)
   where
     fromFilePath = Text.pack . Turtle.encodeString
-    runJsSource = fromFilePath (sourceDir Turtle.</> ".spago/run.js")
     nodeArgs = Text.intercalate " " $ map unBackendArg extraArgs
     nodeContents outputPath' =
       fold
-        [ "#!/usr/bin/env node\n\n"
-        , "require('"
+        [ "require('"
         , Text.replace "\\" "/" (fromFilePath sourceDir)
         , "/"
         , Text.pack outputPath'
         , "/"
         , unModuleName moduleName
         , "').main()"
         ]
-    nodeCmd = "node " <> runJsSource <> " " <> nodeArgs
+    nodeCmd outputPath'= "node -e \"" <> nodeContents outputPath' <> "\" " <> nodeArgs
     nodeAction outputPath' = do
-      logDebug $ "Writing " <> displayShow @Text runJsSource
-      writeTextFile runJsSource (nodeContents outputPath')
-      void $ chmod executable $ pathFromText runJsSource
       -- cd to executeDir in case it isn't the same as sourceDir
       logDebug $ "Executing from: " <> displayShow @FilePath executeDir
       Turtle.cd executeDir
       -- We build a process by hand here because we need to forward the stdin to the backend process
-      let processWithStdin = (Process.shell (Text.unpack nodeCmd)) { Process.std_in = Process.Inherit }
+      logDebug $ "Running node command: `" <> (display $ nodeCmd outputPath') <> "`"
+      let processWithStdin = (Process.shell (Text.unpack $ nodeCmd outputPath')) { Process.std_in = Process.Inherit }
       Turtle.system processWithStdin empty >>= \case
         ExitSuccess   -> maybe (pure ()) (logInfo . display) maybeSuccessMessage
         ExitFailure n -> die [ display failureMessage <> "exit code: " <> repr n ]

test/fixtures/spago-run-args.purs

@@ -10,5 +10,5 @@ import Data.Show (show)
 main :: Effect Unit
 main = do
   args <- argv
-  -- dropping the first two args, node path and script name, to make test stable
-  log $ show $ drop 2 args
+  -- dropping the first arg, node path to make test stable
+  log $ show $ drop 1 args