From a18188d157cd08e45043d3a20c763a183fa0be1f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Wro=C5=84ski?= <lukaszwronski98@gmail.com>
Date: Wed, 28 Dec 2022 12:10:03 +0100
Subject: [PATCH] Remove suffix `.aux` from progName when installed by cs

---
 modules/cli/src/main/scala/scala/cli/ScalaCli.scala | 10 +++++++++-
 .../installcompletions/InstallCompletions.scala     | 12 ++++--------
 .../scala/scala/cli/integration/SipScalaTests.scala | 13 +++++++++++++
 3 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/modules/cli/src/main/scala/scala/cli/ScalaCli.scala b/modules/cli/src/main/scala/scala/cli/ScalaCli.scala
index b95912572a..3105d6d66c 100644
--- a/modules/cli/src/main/scala/scala/cli/ScalaCli.scala
+++ b/modules/cli/src/main/scala/scala/cli/ScalaCli.scala
@@ -4,6 +4,7 @@ import sun.misc.{Signal, SignalHandler}
 
 import java.io.{ByteArrayOutputStream, File, PrintStream}
 import java.nio.charset.StandardCharsets
+import java.nio.file.Paths
 import java.util.Locale
 
 import scala.build.blooprifle.FailedToStartServerException
@@ -21,7 +22,14 @@ object ScalaCli {
     // the Scala CLI native image, no need to manually load it.
     coursier.jniutils.LoadWindowsLibrary.assumeInitialized()
 
-  val progName = (new Argv0).get("scala-cli")
+  val progName = {
+    val argv0 = (new Argv0).get("scala-cli")
+    val last  = Paths.get(argv0).getFileName.toString
+    last match {
+      case s".${name}.aux" => name // cs install binaries under .app-name.aux and add to the PATH
+      case _               => argv0
+    }
+  }
 
   private def checkName(name: String) = {
     val baseProgName = if (Properties.isWin) progName.stripSuffix(".exe") else progName
diff --git a/modules/cli/src/main/scala/scala/cli/commands/installcompletions/InstallCompletions.scala b/modules/cli/src/main/scala/scala/cli/commands/installcompletions/InstallCompletions.scala
index 4249677fb4..7d19cf94bc 100644
--- a/modules/cli/src/main/scala/scala/cli/commands/installcompletions/InstallCompletions.scala
+++ b/modules/cli/src/main/scala/scala/cli/commands/installcompletions/InstallCompletions.scala
@@ -5,12 +5,13 @@ import caseapp.core.complete.{Bash, Zsh}
 
 import java.io.File
 import java.nio.charset.Charset
+import java.nio.file.Paths
 import java.util
 
 import scala.build.Logger
-import scala.cli.CurrentParams
 import scala.cli.commands.ScalaCommand
 import scala.cli.internal.{Argv0, ProfileFileUpdater}
+import scala.cli.{CurrentParams, ScalaCli}
 
 object InstallCompletions extends ScalaCommand[InstallCompletionsOptions] {
   override def names = List(
@@ -101,13 +102,8 @@ object InstallCompletions extends ScalaCommand[InstallCompletionsOptions] {
 
   def getName(name: Option[String]): String =
     name.getOrElse {
-      val baseName = (new Argv0).get(baseRunnerName)
-      val idx      = baseName.lastIndexOf(File.separator)
-      val last     = if (idx < 0) baseName else baseName.drop(idx + 1)
-      last match {
-        case s".${name}.aux" => name // // cs install binaries under .app-name.aux
-        case name            => name
-      }
+      val progName = ScalaCli.progName
+      Paths.get(progName).getFileName.toString
     }
 
   def getFormat(format: Option[String]): Option[String] =
diff --git a/modules/integration/src/test/scala/scala/cli/integration/SipScalaTests.scala b/modules/integration/src/test/scala/scala/cli/integration/SipScalaTests.scala
index 013d77b5e8..a173ae7453 100644
--- a/modules/integration/src/test/scala/scala/cli/integration/SipScalaTests.scala
+++ b/modules/integration/src/test/scala/scala/cli/integration/SipScalaTests.scala
@@ -107,6 +107,19 @@ class SipScalaTests extends ScalaCliSuite {
       }
     }
 
+  if (TestUtil.isNativeCli)
+    test(s"usage instruction should point to scala when installing by cs") { // https://github.com/VirtusLab/scala-cli/issues/1662
+      TestInputs.empty.fromRoot {
+        root => // cs install binaries under .app-name.aux and scala-cli should drop .aux from progName
+          val binary       = "scala".prepareBinary(root)
+          val csBinaryName = root / ".scala.aux"
+          os.move(binary, csBinaryName)
+          val output = os.proc(csBinaryName, "test", "--usage").call(check = false).out.text().trim
+          val usageMsg = TestUtil.removeAnsiColors(output)
+          expect(usageMsg == "Usage: scala test [options]")
+      }
+    }
+
   def testHelpOutput(binaryName: String): Unit = TestInputs.empty.fromRoot { root =>
     val binary = binaryName.prepareBinary(root)
     for { helpOption <- Seq("help", "-help", "--help") } {