More attempts at robustizing BSP (#6056)

Author: lihaoyi

libs/script/src/ScriptModuleInit.scala

@@ -126,18 +126,8 @@ object ScriptModuleInit
     discoverScriptFiles(workspaceRoot, os.Path(mill.constants.OutFiles.out, workspaceRoot))
       .filter(p => !nonScriptSourceFolders.exists(p.startsWith(_)))
       .flatMap { scriptPath =>
-        try {
-          resolveScriptModule(scriptPath.toString, eval.resolveScriptModuleDep).map { result =>
-            (scriptPath.toNIO, result)
-          }
-        } catch {
-          case e: Exception =>
-            // If resolving a script module fails, just log it and ignore
-            // it rather than blowing up the whole BSP import process
-            println("Failed to instantiate script during BSP import and discovery: " + scriptPath)
-            println(e)
-            e.printStackTrace()
-            None
+        resolveScriptModule(scriptPath.toString, eval.resolveScriptModuleDep).map { result =>
+          (scriptPath.toNIO, result)
         }
       }
   }

runner/bsp/worker/src/mill/bsp/worker/BspEvaluators.scala

@@ -86,9 +86,12 @@ private[mill] class BspEvaluators(
       .invoke(null, nonScriptSources, eval)
       .asInstanceOf[Seq[(java.nio.file.Path, mill.api.Result[BspModuleApi])]]
 
-    result.map {
+    result.flatMap {
       case (scriptPath: java.nio.file.Path, mill.api.Result.Success(module: BspModuleApi)) =>
-        (new BuildTargetIdentifier(Utils.sanitizeUri(scriptPath)), (module, eval))
+        Some((new BuildTargetIdentifier(Utils.sanitizeUri(scriptPath)), (module, eval)))
+      case (scriptPath: java.nio.file.Path, mill.api.Result.Failure(msg: String)) =>
+        println(s"Failed to instantiate script module for BSP: $scriptPath failed with $msg")
+        None
     }
   }
   lazy val bspModulesById: Map[BuildTargetIdentifier, (BspModuleApi, EvaluatorApi)] = {