From e1d12f55bffb0992830d6692d79dd4baf74c6359 Mon Sep 17 00:00:00 2001
From: Luigi Frunzio <giggiux@gmail.com>
Date: Thu, 20 May 2021 20:44:02 +0200
Subject: [PATCH 1/2] Add message when trying to attach a session and the
 buildTarget is not defined.

---
 .../scala/scala/meta/internal/metals/Messages.scala   |  7 +++++++
 .../meta/internal/metals/debug/DebugProvider.scala    | 11 +++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/metals/src/main/scala/scala/meta/internal/metals/Messages.scala b/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
index 253c581c5ab..c3202c55de9 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
@@ -487,6 +487,13 @@ object Messages {
       show = true
     )
 
+  def DebugInvalidBuildTargetConf(): MessageParams = {
+    new MessageParams(
+      MessageType.Error,
+      s"Debugger configuration is missing 'buildTarget' param."
+    )
+  }
+
   object DebugClassNotFound {
 
     def invalidTargetClass(cls: String, target: String): MessageParams = {
diff --git a/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala b/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
index faeac2535d9..066b095beea 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
@@ -393,8 +393,8 @@ class DebugProvider(
 
   def resolveAttachRemoteParams(
       params: DebugUnresolvedAttachRemoteParams
-  ): Future[b.DebugSessionParams] =
-    buildTargets.findByDisplayName(params.buildTarget) match {
+  )(implicit ec: ExecutionContext): Future[b.DebugSessionParams] = {
+    val result = buildTargets.findByDisplayName(params.buildTarget) match {
       case Some(target) =>
         Future.successful(
           new b.DebugSessionParams(
@@ -406,6 +406,9 @@ class DebugProvider(
       case None =>
         Future.failed(new ju.NoSuchElementException(params.buildTarget))
     }
+    result.failed.foreach(reportErrors)
+    result
+  }
 
   private val reportErrors: PartialFunction[Throwable, Unit] = {
     case _ if buildClient.buildHasErrors =>
@@ -440,6 +443,10 @@ class DebugProvider(
       languageClient.showMessage(
         Messages.errorMessageParams(e.getMessage())
       )
+    case _: ju.NoSuchElementException =>
+      languageClient.showMessage(
+        Messages.DebugInvalidBuildTargetConf()
+      )
     case e: NoTestsFoundException =>
       languageClient.showMessage(
         Messages.errorMessageParams(e.getMessage())

From 033a93dd4a1509dade966d7f9433fd2aaca23c8f Mon Sep 17 00:00:00 2001
From: Luigi Frunzio <giggiux@gmail.com>
Date: Fri, 21 May 2021 10:28:30 +0200
Subject: [PATCH 2/2] use custom exception

---
 .../main/scala/scala/meta/internal/metals/Messages.scala   | 7 -------
 .../internal/metals/debug/BuildTargetClassesFinder.scala   | 3 +++
 .../scala/meta/internal/metals/debug/DebugProvider.scala   | 6 +++---
 3 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/metals/src/main/scala/scala/meta/internal/metals/Messages.scala b/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
index c3202c55de9..253c581c5ab 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/Messages.scala
@@ -487,13 +487,6 @@ object Messages {
       show = true
     )
 
-  def DebugInvalidBuildTargetConf(): MessageParams = {
-    new MessageParams(
-      MessageType.Error,
-      s"Debugger configuration is missing 'buildTarget' param."
-    )
-  }
-
   object DebugClassNotFound {
 
     def invalidTargetClass(cls: String, target: String): MessageParams = {
diff --git a/metals/src/main/scala/scala/meta/internal/metals/debug/BuildTargetClassesFinder.scala b/metals/src/main/scala/scala/meta/internal/metals/debug/BuildTargetClassesFinder.scala
index d191c498d84..6b90138d189 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/debug/BuildTargetClassesFinder.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/debug/BuildTargetClassesFinder.scala
@@ -143,6 +143,9 @@ class BuildTargetClassesFinder(
 case class BuildTargetNotFoundException(buildTargetName: String)
     extends Exception(s"Build target not found: $buildTargetName")
 
+case class BuildTargetUndefinedException()
+    extends Exception("Debugger configuration is missing 'buildTarget' param.")
+
 case class ClassNotFoundInBuildTargetException(
     className: String,
     buildTarget: b.BuildTarget
diff --git a/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala b/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
index 066b095beea..1eb8fa44431 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/debug/DebugProvider.scala
@@ -404,7 +404,7 @@ class DebugProvider(
           )
         )
       case None =>
-        Future.failed(new ju.NoSuchElementException(params.buildTarget))
+        Future.failed(BuildTargetUndefinedException())
     }
     result.failed.foreach(reportErrors)
     result
@@ -443,9 +443,9 @@ class DebugProvider(
       languageClient.showMessage(
         Messages.errorMessageParams(e.getMessage())
       )
-    case _: ju.NoSuchElementException =>
+    case e: BuildTargetUndefinedException =>
       languageClient.showMessage(
-        Messages.DebugInvalidBuildTargetConf()
+        Messages.errorMessageParams(e.getMessage())
       )
     case e: NoTestsFoundException =>
       languageClient.showMessage(