From 8d065aa3264dc97ea1ed2eee298b6c6ddac80d94 Mon Sep 17 00:00:00 2001
From: exoego <mogami@exoego.net>
Date: Tue, 18 Jun 2019 08:25:14 +0900
Subject: [PATCH] Show user guidance to configuration file if file not exists

---
 .../tanishiking/scalaunfmt/cli/Cli.scala      | 19 +++++++++++++++++--
 .../tanishiking/scalaunfmt/cli/CliSpec.scala  | 14 +++++++++++++-
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/main/scala/com/github/tanishiking/scalaunfmt/cli/Cli.scala b/src/main/scala/com/github/tanishiking/scalaunfmt/cli/Cli.scala
index 5b21389..8ac5fb4 100644
--- a/src/main/scala/com/github/tanishiking/scalaunfmt/cli/Cli.scala
+++ b/src/main/scala/com/github/tanishiking/scalaunfmt/cli/Cli.scala
@@ -1,11 +1,14 @@
 package com.github.tanishiking.scalaunfmt.cli
 
 import java.io.PrintStream
+import java.nio.file.NoSuchFileException
 
 import com.github.tanishiking.scalaunfmt.core.Runner
-import metaconfig.{Conf, Configured}
+import metaconfig.{ Conf, Configured }
 import metaconfig.typesafeconfig._
 
+import scala.util.{ Failure, Success, Try }
+
 object Cli {
   def main(args: Array[String]): Unit = {
     CliArgParser.scoptParser.parse(args, CliOptions()) match {
@@ -22,7 +25,19 @@ object Cli {
 
     val runner = new Runner(errStream)
 
-    Conf.parseFile(confPath.toFile) match {
+    val conf = Try {
+      Conf.parseFile(confPath.toFile)
+    } match {
+      case Success(v) => v
+      case Failure(e: NoSuchFileException) =>
+        throw new IllegalArgumentException(
+          s"""Configuration file ${e.getFile} not found.
+             |Provide the file in reference to https://github.com/tanishiking/scalaunfmt#configuration""".stripMargin
+        )
+      case Failure(e) => throw e // unknown
+    }
+
+    conf match {
       case Configured.Ok(value) =>
         runner.run(
           files,
diff --git a/src/test/scala/com/github/tanishiking/scalaunfmt/cli/CliSpec.scala b/src/test/scala/com/github/tanishiking/scalaunfmt/cli/CliSpec.scala
index 0934e94..48e0295 100644
--- a/src/test/scala/com/github/tanishiking/scalaunfmt/cli/CliSpec.scala
+++ b/src/test/scala/com/github/tanishiking/scalaunfmt/cli/CliSpec.scala
@@ -1,13 +1,25 @@
 package com.github.tanishiking.scalaunfmt.cli
 
 import java.io.{ByteArrayOutputStream, PrintStream}
-import java.nio.file.Files
+import java.nio.file.{Files, NoSuchFileException, Paths}
 
 import org.scalatest.{FunSpec, Matchers}
 
 class CliSpec extends FunSpec with Matchers {
   describe("Cli") {
     describe("run") {
+      it("should show error message to guide users to create a config file") {
+        val configPath = Paths.get("NO.SUCH.FILE.conf")
+        val opt = CliOptions(
+          config = configPath,
+          version = "2.0.0-RC5"
+        )
+        val ex = intercept[IllegalArgumentException] {
+          Cli.run(opt, System.out, System.err)
+        }
+        assert(ex.getMessage.contains("Configuration file NO.SUCH.FILE.conf not found."))
+      }
+
       it("should throw exception for unparsable config") {
         val configPath = Files.createTempFile("temp", ".conf")
         val unparsableConf =