Be better at starting Code on various OS

- On OS X, use "open -a" so that code does not need to be added to the PATH
- On Windows, use "cmd.exe /C" since that seems to be required to look
  in the PATH
On every OS, pass "-n" to Code to start a new instance, this makes
things more reproducible.

Author: smarter

docs/docs/usage/ide-support.md

@@ -17,9 +17,7 @@ Dotty, please follow the instructions at https://github.com/lampepfl/dotty-examp
 Usage
 =====
 1. Install [Visual Studio Code](https://code.visualstudio.com/).
-2. Make sure `code`, the binary for Visual Studio Code, is on your `$PATH`, this
-   is the case if you can start the IDE by running `code` in a terminal.
-3. In your project, run:
+2. In your project, run:
 ```shell
 sbt launchIDE
 ```

project/Build.scala

@@ -15,6 +15,7 @@ import sbt.Package.ManifestAttributes
 import com.typesafe.sbteclipse.plugin.EclipsePlugin._
 
 import dotty.tools.sbtplugin.DottyPlugin.autoImport._
+import dotty.tools.sbtplugin.DottyIDEPlugin.runProcess
 import dotty.tools.sbtplugin.DottyIDEPlugin.autoImport._
 import org.scalajs.sbtplugin.ScalaJSPlugin
 import org.scalajs.sbtplugin.ScalaJSPlugin.autoImport._
@@ -766,8 +767,13 @@ object Build {
         val mainClass = "dotty.tools.languageserver.Main"
         val extensionPath = (baseDirectory in `vscode-dotty`).value.getAbsolutePath
 
-        val codeArgs = if (inputArgs.isEmpty) List((baseDirectory.value / "..").getAbsolutePath) else inputArgs
-        val allArgs = List("-client_command", "code", s"--extensionDevelopmentPath=$extensionPath") ++ codeArgs
+        val codeArgs =
+          s"--extensionDevelopmentPath=$extensionPath" +:
+            (if (inputArgs.isEmpty) List((baseDirectory.value / "..").getAbsolutePath) else inputArgs)
+
+        val clientCommand = codeCommand.value ++ codeArgs
+
+        val allArgs = "-client_command" +: clientCommand
 
         runTask(Runtime, mainClass, allArgs: _*)
       }.dependsOn(compile in (`vscode-dotty`, Compile)).evaluated
@@ -944,12 +950,7 @@ object Build {
         // Currently, vscode-dotty depends on daltonjorge.scala for syntax highlighting,
         // this is not automatically installed when starting the extension in development mode
         // (--extensionDevelopmentPath=...)
-        val exitCodeInstall = new java.lang.ProcessBuilder("code", "--install-extension", "daltonjorge.scala")
-          .inheritIO()
-          .start()
-          .waitFor()
-        if (exitCodeInstall != 0)
-          throw new MessageOnlyException("Installing dependency daltonjorge.scala failed")
+        runProcess(codeCommand.value ++ Seq("--install-extension", "daltonjorge.scala"), wait = true)
 
         sbt.inc.Analysis.Empty
       },
@@ -986,14 +987,9 @@ object Build {
         val inputArgs = spaceDelimited("<arg>").parsed
         val codeArgs = if (inputArgs.isEmpty) List((baseDirectory.value / "..").getAbsolutePath) else inputArgs
         val extensionPath = baseDirectory.value.getAbsolutePath
-        val processArgs = List("code", s"--extensionDevelopmentPath=${extensionPath}") ++ codeArgs
+        val processArgs = List(s"--extensionDevelopmentPath=${extensionPath}") ++ codeArgs
 
-        val exitCode = new java.lang.ProcessBuilder(processArgs: _*)
-          .inheritIO()
-          .start()
-          .waitFor()
-        if (exitCode != 0)
-          throw new MessageOnlyException("Running Visual Studio Code failed")
+        runProcess(codeCommand.value ++ processArgs, wait = true)
       }.dependsOn(compile in Compile).evaluated
     )
 

sbt-dotty/src/dotty/tools/sbtplugin/DottyIDEPlugin.scala

@@ -5,6 +5,7 @@ import sbt.Keys._
 import java.io._
 import java.lang.ProcessBuilder
 import scala.collection.mutable
+import scala.util.Properties.{ isWin, isMac }
 
 import dotty.tools.languageserver.config.ProjectConfig
 
@@ -123,9 +124,24 @@ object DottyIDEPlugin extends AutoPlugin {
     runTask(joinedTask, state)
   }
 
+  def runProcess(cmd: Seq[String], wait: Boolean = false, directory: File = null): Unit = {
+    val pb0 = new ProcessBuilder(cmd: _*).inheritIO()
+    val pb = if (directory != null) pb0.directory(directory) else pb0
+    if (wait) {
+      val exitCode = pb.start().waitFor()
+      if (exitCode != 0) {
+        val cmdString = cmd.mkString(" ")
+        throw new MessageOnlyException("""Running command "${cmdString}" failed.""")
+      }
+    }
+    else
+      pb.start()
+  }
+
   private val projectConfig = taskKey[Option[ProjectConfig]]("")
 
   object autoImport {
+    val codeCommand = taskKey[Seq[String]]("Command to start VSCode")
     val runCode = taskKey[Unit]("Start VSCode, usually called from launchIDE")
     val launchIDE = taskKey[Unit]("Configure and run VSCode on this project")
   }
@@ -203,17 +219,18 @@ object DottyIDEPlugin extends AutoPlugin {
   override def buildSettings: Seq[Setting[_]] = Seq(
     commands ++= Seq(configureIDE, compileForIDE),
 
+    codeCommand := {
+      if (isWin)
+        Seq("cmd.exe", "/C", "code", "-n")
+      else if (isMac)
+        Seq("open", "-a", "Visual Studio Code", "--args", "-n")
+      else
+        Seq("code", "-n")
+    },
+
     runCode := {
-      val exitCode = new ProcessBuilder("code", "--install-extension", "lampepfl.dotty")
-        .inheritIO()
-        .start()
-        .waitFor()
-      if (exitCode != 0)
-        throw new MessageOnlyException("Installing the Dotty support for VSCode failed")
-
-      new ProcessBuilder("code", baseDirectory.value.getAbsolutePath)
-        .inheritIO()
-        .start()
+      runProcess(codeCommand.value ++ Seq("--install-extension", "lampepfl.dotty"), wait = true)
+      runProcess(codeCommand.value ++ Seq("."), directory = baseDirectory.value)
     }
 
   ) ++ addCommandAlias("launchIDE", ";configureIDE;runCode")

vscode-dotty/README.md

@@ -5,10 +5,7 @@ To use this in your own Scala project, you must first get it to compile with
 Dotty, please follow the instructions at https://github.com/lampepfl/dotty-example-project
 
 ## Starting Visual Studio Code from sbt
-First, make sure `code`, the binary for Visual Studio Code, is on your `$PATH`,
-this is the case if you can start the IDE by running `code` in a terminal.
-
-If this is the case and your project succesfully compiles with dotty, you can
+Once your project succesfully compiles with dotty, you can
 simply use the `launchIDE` command provided by the sbt-dotty plugin:
 
 ```shell