Added --repl and --no-server and changed behavior of -i/--interactive for #926

build.sc

@@ -597,7 +597,7 @@ def launcherScript(shellJvmArgs: Seq[String],
          |    COURSIER_CACHE=.coursier ${java("mill.MillMain")}
          |else
          |    case "$$1" in
-         |      -i | --interactive )
+         |      -i | --interactive | --repl | --no-server )
          |        ${java("mill.MillMain")}
          |        ;;
          |      *)
@@ -616,6 +616,8 @@ def launcherScript(shellJvmArgs: Seq[String],
          |if not "%JAVA_HOME%"=="" set "JAVACMD=%JAVA_HOME%\\bin\\java.exe"
          |if "%1" == "-i" set _I_=true
          |if "%1" == "--interactive" set _I_=true
+         |if "%1" == "--repl" set _I_=true
+         |if "%1" == "--no-server" set _I_=true
          |if defined _I_ (
          |  ${java("mill.MillMain")}
          |) else (

docs/pages/1 - Intro to Mill.md

@@ -65,7 +65,9 @@ Mill also works on a sh environment on Windows (e.g.,
 [WSL](https://docs.microsoft.com/en-us/windows/wsl);
 to get started, follow the instructions in the [manual](#manual) section below. Note that:
 
-* In some environments (such as WSL), mill might have to be run using interactive mode (`-i`)
+* In some environments (such as WSL), mill might have to be run
+  without a server (using `-i`, `--interactive`, `--no-server`, or
+  `--repl`.)
 
 * On Cygwin, run the following after downloading mill:
 
@@ -707,10 +709,10 @@ generate an IntelliJ project config for your build.
 This also configures IntelliJ to allow easy navigate & code-completion within
 your build file itself.
 
-## The Build Repl
+## The Build REPL
 
 ```bash
-$ mill -i
+$ mill --repl
 Loading...
 @ foo
 res0: foo.type = ammonite.predef.build#foo:4
@@ -747,10 +749,10 @@ res2: mill.scalalib.api.CompilationResult = CompilationResult(
 )
 ```
 
-You can run `mill -i` to open a build REPL; this is a Scala console with your
-`build.sc` loaded, which lets you run tasks interactively. The task-running
-syntax is slightly different from the command-line, but more in-line with how
-you would depend on tasks from within your build file.
+You can run `mill --repl` to open a build REPL; this is a Scala console with
+your `build.sc` loaded, which lets you run tasks interactively. The
+task-running syntax is slightly different from the command-line, but more
+in-line with how you would depend on tasks from within your build file.
 
 You can use this REPL to interactively explore your build to see what is available.
 

docs/pages/2 - Configuring Mill.md

@@ -297,10 +297,11 @@ the same testing framework, etc. and all that can be extracted out into the
 
 Mill builds on ammonite which allows you to
 [define global configuration](http://ammonite.io/#ScriptPredef). Depending on
-how you start mill 2 different files will be loaded. For interactive mode it's
-`~/.mill/ammonite/predef.sc` and from the command line it's
-`~/.mill/ammonite/predefScript.sc`. You might want to create a symlink from one
-to the other to avoid duplication.
+how you start mill, one of two files will be loaded. For the build REPL
+(`--repl` or `-i` without specifying a target), `~/.mill/ammonite/predef.sc`
+will be loaded, and for builds from the command line the file
+`~/.mill/ammonite/predefScript.sc` will be included. You might want to create
+a symlink from one to the other to avoid duplication.
 
 Example `~/.mill/ammonite/predef.sc`
 ```scala

main/src/MillMain.scala

@@ -13,13 +13,8 @@ import mill.api.DummyInputStream
 object MillMain {
 
   def main(args: Array[String]): Unit = {
-    // Remove the trailing interactive parameter, we already handled it on call site
-    val as = args match {
-      case Array(s, _*) if s == "-i" || s == "--interactive" => args.tail
-      case _ => args
-    }
     val (result, _) = main0(
-      as,
+      args,
       None,
       ammonite.Main.isInteractive(),
       System.in,
@@ -49,11 +44,32 @@ object MillMain {
 
     val removed = Set("predef-code", "no-home-predef")
 
+    var repl = false
+    val replSignature = Arg[Config, Unit](
+      "repl", None,
+      "Run Mill in interactive mode and start a build REPL. In this mode, no mill server will be used. Must be the first argument.",
+      (c, v) => {
+        repl = true
+        c
+      }
+    )
+
+    var noServer = false
+    val noServerSignature = Arg[Config, Unit](
+      "no-server", None,
+      "Run Mill in interactive mode, suitable for opening REPLs and taking user input. In this mode, no mill server will be used. Must be the first argument.",
+      (c, v) => {
+        noServer = true
+        c
+      }
+    )
+
     var interactive = false
     val interactiveSignature = Arg[Config, Unit](
       "interactive", Some('i'),
-      "Run Mill in interactive mode, suitable for opening REPLs and taking user input. In this mode, no mill server will be used.",
+      "Run Mill in interactive mode, suitable for opening REPLs and taking user input. In this mode, no mill server will be used. Must be the first argument.",
       (c, v) => {
+        // check for stdin == DummyInputStream, which means this wasn't handled
         interactive = true
         c
       }
@@ -134,6 +150,8 @@ object MillMain {
     val millArgSignature =
       Cli.genericSignature.filter(a => !removed(a.name)) ++
         Seq(
+          replSignature,
+          noServerSignature,
           interactiveSignature,
           showVersionSignature,
           disableTickerSignature,
@@ -149,10 +167,14 @@ object MillMain {
       millArgSignature,
       Cli.Config(home = millHome, remoteLogging = false)
     ) match {
-      case _ if interactive =>
+      case _ if (interactive || repl || noServer)
+                  && stdin == DummyInputStream =>
         // because this parameter was handled earlier (when in first position),
         // here it is too late and we can't handle it properly.
-        stderr.println("-i/--interactive must be passed in as the first argument")
+        stderr.println("-i/--interactive/--repl/--no-server must be passed in as the first argument")
+        (false, None)
+      case _ if Seq(interactive, repl, noServer).count(identity) > 1 =>
+        stderr.println("Only one of -i/--interactive, --repl, or --no-server may be given")
         (false, None)
       case Left(msg) =>
         stderr.println(msg)
@@ -177,16 +199,24 @@ object MillMain {
         (true, None)
 
       case Right((cliConfig, leftoverArgs)) =>
-
-        val repl = leftoverArgs.isEmpty
-        if (repl && stdin == DummyInputStream) {
-          stderr.println("Build repl needs to be run with the -i/--interactive flag")
+        val useRepl = repl || (interactive && leftoverArgs.isEmpty)
+        if ( repl && leftoverArgs.nonEmpty ) {
+          stderr.println("No target may be provided with the --repl flag")
+          (false, stateCache)
+        } else if ( leftoverArgs.isEmpty && noServer ) {
+          stderr.println("A target must be provided when not starting a build REPL")
+          (false, stateCache)
+        } else if ( useRepl && stdin == DummyInputStream ) {
+          stderr.println("Build REPL needs to be run with the -i/--interactive/--repl flag")
           (false, stateCache)
         }else{
+          if ( useRepl && interactive ) {
+            stderr.println("WARNING: Starting a build REPL without --repl is deprecated")
+          }
           val systemProps = initialSystemProperties ++ extraSystemProperties
 
           val config =
-            if(!repl) cliConfig
+            if(!useRepl) cliConfig
             else cliConfig.copy(
               predefCode =
                 s"""import $$file.build, build._
@@ -232,7 +262,7 @@ object MillMain {
               }
             }
 
-            if (repl) {
+            if (useRepl) {
               runner.printInfo("Loading...")
               (runner.watchLoop(isRepl = true, printing = false, _.run()), runner.stateCache)
             } else {