add allCredentials to emulate credential registration

Fixes #4802

For Ivy integration sbt uses credential task in a peculiar way. 9fa25de84c/main/src/main/scala/sbt/Defaults.scala (L2271-L2275)

This lets the build user put `credential` task in various places, like metabuild or root project, but they would all act as if they were scoped globally. This PR adds `allCredentials` task to emulate the behavior to pass credentials into lm-coursier.

main/src/main/scala/sbt/Defaults.scala

@@ -2364,6 +2364,7 @@ object Classpaths {
     ),
     ivySbt := ivySbt0.value,
     ivyModule := { val is = ivySbt.value; new is.Module(moduleSettings.value) },
+    allCredentials := LMCoursier.allCredentialsTask.value,
     transitiveUpdate := transitiveUpdateTask.value,
     updateCacheName := {
       val binVersion = scalaBinaryVersion.value

main/src/main/scala/sbt/Keys.scala

@@ -376,6 +376,7 @@ object Keys {
   val packagedArtifacts = taskKey[Map[Artifact, File]]("Packages all artifacts for publishing and maps the Artifact definition to the generated file.").withRank(CTask)
   val publishMavenStyle = settingKey[Boolean]("Configures whether to generate and publish a pom (true) or Ivy file (false).").withRank(BSetting)
   val credentials = taskKey[Seq[Credentials]]("The credentials to use for updating and publishing.").withRank(BMinusTask)
+  val allCredentials = taskKey[Seq[Credentials]]("Aggregated credentials.").withRank(DTask)
 
   val makePom = taskKey[File]("Generates a pom for publishing when publishing Maven-style.").withRank(BPlusTask)
   val deliver = taskKey[File]("Generates the Ivy file for publishing to a repository.").withRank(BTask)

main/src/main/scala/sbt/coursierint/CoursierInputsTasks.scala

@@ -204,7 +204,7 @@ object CoursierInputsTasks {
 
   val credentialsTask = Def.task {
     val log = streams.value.log
-    val creds = sbt.Keys.credentials.value
+    val creds = sbt.Keys.allCredentials.value
       .flatMap {
         case dc: IvyDirectCredentials => List(dc)
         case fc: FileCredentials =>

main/src/main/scala/sbt/coursierint/LMCoursier.scala

@@ -9,6 +9,7 @@ package sbt
 package coursierint
 
 import java.io.File
+import scala.collection.mutable
 import lmcoursier.definitions.{
   Classifier,
   Configuration => CConfiguration,
@@ -19,11 +20,15 @@ import lmcoursier._
 import lmcoursier.credentials.Credentials
 import Keys._
 import sbt.librarymanagement._
+import sbt.librarymanagement.ivy.{ Credentials => IvyCredentials }
 import sbt.util.Logger
 import sbt.io.syntax._
 import xsbti.AppConfiguration
 
 object LMCoursier {
+  private[sbt] val credentialRegistry: mutable.Map[(String, String), IvyCredentials] =
+    mutable.Map.empty
+
   def defaultCacheLocation: File =
     sys.props.get("sbt.coursier.home") match {
       case Some(home) => new File(home).getAbsoluteFile / "cache"
@@ -188,4 +193,17 @@ object LMCoursier {
   def publicationsSetting(packageConfigs: Seq[(Configuration, CConfiguration)]): Def.Setting[_] = {
     csrPublications := CoursierArtifactsTasks.coursierPublicationsTask(packageConfigs: _*).value
   }
+
+  private[sbt] def registerCredentials(creds: IvyCredentials): Unit = {
+    val d = IvyCredentials.toDirect(creds)
+    credentialRegistry((d.host, d.realm)) = d
+  }
+
+  // This emulates Ivy's credential registration which basically keeps mutating global registry
+  def allCredentialsTask: Def.Initialize[Task[Seq[IvyCredentials]]] = Def.task {
+    (Keys.credentials in ThisBuild).value foreach registerCredentials
+    (Keys.credentials in LocalRootProject).value foreach registerCredentials
+    Keys.credentials.value foreach registerCredentials
+    credentialRegistry.values.toVector
+  }
 }