throw Result.Failure for prettier error messages

main/server/src/mill/main/server/Server.scala

@@ -6,7 +6,7 @@ import scala.jdk.CollectionConverters._
 import org.newsclub.net.unix.AFUNIXServerSocket
 import org.newsclub.net.unix.AFUNIXSocketAddress
 import mill.main.client._
-import mill.api.SystemStreams
+import mill.api.{Result, SystemStreams}
 import mill.main.client.ProxyStream.Output
 import mill.main.client.lock.{Lock, Locks}
 
@@ -63,7 +63,7 @@ abstract class Server[T](
           }
         ) ()
 
-      }.getOrElse(throw new Exception("Mill server process already present"))
+      }.getOrElse(throw Result.Failure("Mill server process already present"))
     finally exitServer()
   }
 

main/util/src/mill/util/Jvm.scala

@@ -185,7 +185,8 @@ object Jvm extends CoursierSupport {
       Runtime.getRuntime().removeShutdownHook(shutdownHook)
     }
     if (process.exitCode() == 0) ()
-    else throw new Exception("Interactive Subprocess Failed (exit code " + process.exitCode() + ")")
+    else
+      throw Result.Failure("Interactive Subprocess Failed (exit code " + process.exitCode() + ")")
   }
 
   /**

scalalib/api/src/mill/scalalib/api/ZincWorkerUtil.scala

@@ -1,7 +1,7 @@
 package mill.scalalib.api
 
 import mill.api.Loose.Agg
-import mill.api.PathRef
+import mill.api.{PathRef, Result}
 import scala.util.matching.Regex
 
 trait ZincWorkerUtil {
@@ -38,7 +38,7 @@ trait ZincWorkerUtil {
 
     classPath.iterator
       .find(pathRef => mavenStyleMatch(pathRef.path.last) || ivyStyleMatch(pathRef.path))
-      .getOrElse(throw new Exception(
+      .getOrElse(throw Result.Failure(
         s"Cannot find **/$name-$versionPrefix*$suffix or **/$versionPrefix*/$dir/$name$suffix in ${classPath.iterator.mkString("[", ", ", "]")}"
       ))
   }
@@ -68,7 +68,7 @@ trait ZincWorkerUtil {
 
   def scalaJSBinaryVersion(scalaJSVersion: String): String = scalaJSVersion match {
     case _ if scalaJSVersion.startsWith("0.6.") =>
-      throw new Exception("Scala.js 0.6 is not supported")
+      throw Result.Failure("Scala.js 0.6 is not supported")
     case ScalaJSFullVersion(major, minor, patch, suffix) =>
       if (suffix != null && minor == "0" && patch == "0")
         s"$major.$minor$suffix"
@@ -78,7 +78,7 @@ trait ZincWorkerUtil {
 
   def scalaJSWorkerVersion(scalaJSVersion: String): String = scalaJSVersion match {
     case _ if scalaJSVersion.startsWith("0.6.") =>
-      throw new Exception("Scala.js 0.6 is not supported")
+      throw Result.Failure("Scala.js 0.6 is not supported")
     case ScalaJSFullVersion(major, _, _, _) =>
       major
   }

scalalib/src/mill/scalalib/CrossModuleBase.scala

@@ -1,6 +1,7 @@
 package mill.scalalib
 
 import mill.T
+import mill.api.Result
 import mill.define.Cross
 import mill.define.Cross.Resolver
 import mill.scalalib.api.ZincWorkerUtil
@@ -31,7 +32,7 @@ trait CrossModuleBase extends ScalaModule with Cross.Module[String] {
           )
           .collectFirst { case x => x }
           .getOrElse(
-            throw new Exception(
+            throw Result.Failure(
               s"Unable to find compatible cross version between $crossScalaVersion and " +
                 c.crossModules.map(_.crossScalaVersion).mkString(",")
             )

scalalib/src/mill/scalalib/Dep.scala

@@ -1,12 +1,12 @@
 package mill.scalalib
 
-import upickle.default.{macroRW, ReadWriter => RW}
+import coursier.core.{Configuration, Dependency}
+import mill.api.Result
 import mill.scalalib.CrossVersion._
-import coursier.core.Dependency
 import mill.scalalib.api.ZincWorkerUtil
+import upickle.default.{macroRW, ReadWriter => RW}
 
 import scala.annotation.unused
-import coursier.core.Configuration
 
 case class Dep(dep: coursier.Dependency, cross: CrossVersion, force: Boolean) {
   require(
@@ -110,8 +110,8 @@ object Dep {
       s.split('=') match {
         case Array("classifier", v) => as.withClassifier(coursier.Classifier(v))
         case Array("type", v) => as.withType(coursier.Type(v))
-        case Array(k, v) => throw new Exception(s"Unrecognized attribute: [$s]")
-        case _ => throw new Exception(s"Unable to parse attribute specifier: [$s]")
+        case Array(k, v) => throw Result.Failure(s"Unrecognized attribute: [$s]")
+        case _ => throw Result.Failure(s"Unable to parse attribute specifier: [$s]")
       }
     }
     (module.split(':') match {
@@ -121,7 +121,7 @@ object Dep {
       case Array(a, "", b, "", c) => Dep(a, b, c, cross = Binary(platformed = true))
       case Array(a, "", "", b, c) => Dep(a, b, c, cross = Full(platformed = false))
       case Array(a, "", "", b, "", c) => Dep(a, b, c, cross = Full(platformed = true))
-      case _ => throw new Exception(s"Unable to parse signature: [$signature]")
+      case _ => throw Result.Failure(s"Unable to parse signature: [$signature]")
     }).configure(attributes = attributes)
   }
   def apply(

scalalib/src/mill/scalalib/PublishModule.scala

@@ -20,7 +20,7 @@ trait PublishModule extends JavaModule { outer =>
   override def moduleDeps: Seq[PublishModule] = super.moduleDeps.map {
     case m: PublishModule => m
     case other =>
-      throw new Exception(
+      throw Result.Failure(
         s"PublishModule moduleDeps need to be also PublishModules. $other is not a PublishModule"
       )
   }

scalalib/src/mill/scalalib/ZincWorkerModule.scala

@@ -76,7 +76,7 @@ trait ZincWorkerModule extends mill.Module with OfflineSupportModule { self: Cou
             scalaCompilerBridgeJar(x, y, repositoriesTask())
               .asSuccess
               .getOrElse(
-                throw new Exception(s"Failed to load compiler bridge for $x $y")
+                throw Result.Failure(s"Failed to load compiler bridge for $x $y")
               )
               .value
         )),

scalalib/src/mill/scalalib/publish/SonatypeHttpApi.scala

@@ -5,18 +5,16 @@ import java.util.Base64
 import scala.annotation.tailrec
 import scala.concurrent.duration._
 
+import mill.api.Result
 import mill.main.BuildInfo
-import requests.BaseSession
-import ujson.ParseException
-import requests.Session
 
 class SonatypeHttpApi(
     uri: String,
     credentials: String,
     readTimeout: Int,
     connectTimeout: Int
 ) {
-  val http: Session = requests.Session(
+  val http: requests.Session = requests.Session(
     readTimeout = readTimeout,
     connectTimeout = connectTimeout,
     maxRedirects = 0,
@@ -29,7 +27,9 @@ class SonatypeHttpApi(
     "Authorization" -> s"Basic $base64Creds",
     "Accept" -> "application/json",
     "Content-Type" -> "application/json",
-    "User-Agent" -> s"mill-${BuildInfo.millVersion}${BaseSession.defaultHeaders.get("User-Agent").map(" (" + _ + ")").getOrElse("")}"
+    "User-Agent" -> s"mill-${BuildInfo.millVersion}${requests.BaseSession.defaultHeaders.get(
+        "User-Agent"
+      ).map(" (" + _ + ")").getOrElse("")}"
   )
 
   // https://oss.sonatype.org/nexus-staging-plugin/default/docs/path__staging_profiles.html
@@ -42,7 +42,7 @@ class SonatypeHttpApi(
     )
 
     if (!response.is2xx) {
-      throw new Exception(s"$uri/staging/profiles returned ${response.statusCode}")
+      throw Result.Failure(s"$uri/staging/profiles returned ${response.statusCode}")
     }
 
     val resourceUri =
@@ -67,7 +67,7 @@ class SonatypeHttpApi(
     try {
       ujson.read(response.text())("type").str
     } catch {
-      case e: ParseException =>
+      case e: ujson.ParseException =>
         throw new RuntimeException(
           s"Could not parse HTTP response. ${e.getMessage()}" + "\n" + s"Raw response: ${response}",
           e