add a setting for repositories to fetch artifact metadata from

sbt-version-policy/src/main/scala/sbtversionpolicy/SbtVersionPolicyMima.scala

@@ -2,7 +2,7 @@ package sbtversionpolicy
 
 import scala.collection.JavaConverters.*
 import scala.util.control.NoStackTrace
-import sbt.{AutoPlugin, Def, Keys, settingKey, taskKey}
+import sbt.{AutoPlugin, Def, Keys, PluginTrigger, Plugins, settingKey, taskKey}
 import sbt.KeyRanks.Invisible
 import sbt.librarymanagement.{CrossVersion, ModuleID}
 import coursier.version.{Previous, Version, VersionCompatibility}
@@ -11,12 +11,17 @@ import MimaPlugin.autoImport.mimaPreviousArtifacts
 
 object SbtVersionPolicyMima extends AutoPlugin {
 
-  override def trigger = allRequirements
-  override def requires = MimaPlugin
+  override def trigger: PluginTrigger = allRequirements
+  override def requires: Plugins = MimaPlugin && SbtVersionPolicyPlugin
 
   object autoImport {
     val versionPolicyPreviousVersions = settingKey[Either[Throwable, Seq[String]]]("Previous versions to check compatibility against.")
     val versionPolicyFirstVersion = settingKey[Option[String]]("First version this module was or will be published for.")
+    val versionPolicyPreviousVersionRepositories = settingKey[PreviousVersionRepositories]("Repositories from which to look for previous versions of the artifact. The value can be either `CoursierDefaultRepositories` or `SbtResolvers(Set(resolverNames))`")
+
+    sealed trait PreviousVersionRepositories
+    case object CoursierDefaultRepositories extends PreviousVersionRepositories
+    case class SbtResolvers(resolverNames: Set[String]) extends PreviousVersionRepositories
 
     private[sbtversionpolicy] val getVersionPolicyPreviousVersions =
       taskKey[Seq[String]]("Get previous versions or throw the error if it failed to resolve at load time").withRank(Invisible)
@@ -36,27 +41,52 @@ object SbtVersionPolicyMima extends AutoPlugin {
 
   private lazy val previousVersionsFromRepo = Def.setting[Either[Throwable, Seq[String]]] {
 
+    val version = Keys.version.value
     val projId = Keys.projectID.value
     val sv = Keys.scalaVersion.value
     val sbv = Keys.scalaBinaryVersion.value
     val log = Keys.sLog.value
     val name = moduleName(projId, sv, sbv)
 
     val ivyProps = sbtversionpolicy.internal.Resolvers.defaultIvyProperties(Keys.ivyPaths.value.ivyHome)
-    val repos = Keys.resolvers.value.flatMap { res =>
-      val repoOpt = sbtversionpolicy.internal.Resolvers.repository(res, ivyProps, s => System.err.println(s))
-      if (repoOpt.isEmpty)
-        System.err.println(s"Warning: ignoring repository ${res.name} to get previous version")
-      repoOpt.toSeq
+
+    val repos = versionPolicyPreviousVersionRepositories.?.value match {
+      case None =>
+        // when it is necessary to fetch the artifact metadata but the repositories is not configured
+        // we throw instead of fallback to some defaults, because a mis-configuration of the setting
+        // may let the version policy check pass when it should not.
+        sys.error(
+          s"""Previous version cannot be calculated from the the current version $name:$version.
+             |Please set `versionPolicyPreviousVersionRepositories` for where to fetch the artifact metadata.
+             |Run `inspect versionPolicyPreviousVersionRepositories` for description of valid values.
+             |""".stripMargin
+        )
+
+      case Some(CoursierDefaultRepositories) =>
+        val repositories = coursierapi.Repository.defaults().asScala
+        log.info(s"Getting previous versions of $name from coursier default repositories: ${repositories.mkString("\n", "\n", "")}")
+        repositories
+
+      case Some(SbtResolvers(resolverNames)) =>
+        log.info(s"Getting previous versions of $name from resolvers: ${resolverNames.mkString("\n", "\n", "")}")
+        val resolvers = Keys.resolvers.value.map(res => res.name -> res).toMap
+        val previousVersionResolvers = resolverNames.collect(resolvers).toSeq
+        val unrecognizedResolvers = resolverNames -- previousVersionResolvers.map(_.name)
+        if (unrecognizedResolvers.nonEmpty) {
+          sys.error(s"""Unrecognized resolver names: ${unrecognizedResolvers.mkString(", ")}""")
+        }
+        previousVersionResolvers.flatMap { res =>
+          val repoOpt = sbtversionpolicy.internal.Resolvers.repository(res, ivyProps, s => System.err.println(s))
+          if (repoOpt.isEmpty)
+            sys.error(s"Warning: ignoring repository ${res.name} to get previous version")
+          repoOpt
+        }
     }
-    // Can't reference Keys.fullResolvers, which is a task.
-    // So we're using the usual default repositories from coursier here…
-    val fullRepos = coursierapi.Repository.defaults().asScala ++ repos
 
     val start = System.nanoTime()
 
     val res = coursierapi.Versions.create()
-      .withRepositories(fullRepos: _*)
+      .withRepositories(repos: _*)
       .withModule(coursierapi.Module.of(projId.organization, name))
       .versions()
 

sbt-version-policy/src/sbt-test/sbt-version-policy/aggregate-assessed-compatibility/build.sbt

@@ -1,3 +1,5 @@
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
+
 // A project with two modules (“a” and “b”) and a root module that aggregates them
 
 val v1_a =

sbt-version-policy/src/sbt-test/sbt-version-policy/api-url/build.sbt

@@ -17,7 +17,7 @@ lazy val a = project
 inThisBuild(List(
   scalaVersion := "2.12.11",
   organization := "io.github.alexarchambault.sbtversionpolicy.test",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))
 
 lazy val check = taskKey[Unit]("")
-

sbt-version-policy/src/sbt-test/sbt-version-policy/assess-compatibility-level/build.sbt

@@ -1,6 +1,7 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
 ThisBuild / versionScheme := Some("semver-spec")
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val checkTasks = Seq(
   TaskKey[Unit]("checkAssessedCompatibilityIsBinaryAndSourceCompatible") := {

sbt-version-policy/src/sbt-test/sbt-version-policy/defaults/build.sbt

@@ -1,4 +1,5 @@
 ThisBuild / versionPolicyIntention := Compatibility.BinaryCompatible
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 lazy val v1 = project
   .settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/dependency-schemes/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / scalaVersion := "2.13.6"
 ThisBuild / organization := "ch.epfl.scala"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val b1 = project
   .settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/dependency-source-incompatibilities/build.sbt

@@ -131,4 +131,5 @@ inThisBuild(List(
   scalaVersion := "2.12.11",
   libraryDependencySchemes += "org.typelevel" %% "cats-kernel" % "semver-spec",
   organization := "io.github.alexarchambault.sbtversionpolicy.test",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-ci-release/build.sbt

@@ -11,6 +11,7 @@ inThisBuild(List(
     )
   ),
   scalaVersion := "3.0.1",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
   versionPolicyIntention := Compatibility.BinaryAndSourceCompatible
 ))
 

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-dynver/build.sbt

@@ -5,6 +5,7 @@ ThisBuild / versionPolicyIntention := Compatibility.None
 // Don’t check dependencies to internal modules when the version is like `1.2.3+4-abcd1234` (which
 // is typically the version value generated by sbt-dynver in-between releases)
 ThisBuild / versionPolicyIgnoredInternalDependencyVersions := Some("^\\d+\\.\\d+\\.\\d+\\+\\d+".r)
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val a =
   project

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/build.sbt

@@ -14,7 +14,8 @@ inThisBuild(List(
       url("https://github.com/julienrf")
     )
   ),
-  scalaVersion := "3.0.1"
+  scalaVersion := "3.0.1",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))
 
 val module =

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release/build.sbt

@@ -14,7 +14,8 @@ inThisBuild(List(
       url("https://github.com/julienrf")
     )
   ),
-  scalaVersion := "3.0.1"
+  scalaVersion := "3.0.1",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))
 
 val module = project

sbt-version-policy/src/sbt-test/sbt-version-policy/export-compatibility-report/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val v1_a =
   project

sbt-version-policy/src/sbt-test/sbt-version-policy/first-version/build.sbt

@@ -1,3 +1,4 @@
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 lazy val a = project
   .settings(
@@ -22,4 +23,3 @@ lazy val b = project
   )
 
 lazy val check = taskKey[Unit]("")
-

sbt-version-policy/src/sbt-test/sbt-version-policy/ignored-internal-sbt-plugin/build.sbt

@@ -1,6 +1,7 @@
 ThisBuild / scalaVersion := "2.12.19"
 ThisBuild / organization := "com.example"
 ThisBuild / versionPolicyIntention := Compatibility.BinaryAndSourceCompatible
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val a_1 =
   project

sbt-version-policy/src/sbt-test/sbt-version-policy/in-this-build/build.sbt

@@ -20,6 +20,6 @@ inThisBuild(List(
   scalaVersion := "2.12.11",
   organization := "io.github.alexarchambault.sbtversionpolicy.test2",
   versionPolicyIntention := Compatibility.BinaryCompatible,
-  libraryDependencySchemes += "org.scala-lang.modules" %% "scala-xml" % "early-semver"
+  libraryDependencySchemes += "org.scala-lang.modules" %% "scala-xml" % "early-semver",
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))
-

sbt-version-policy/src/sbt-test/sbt-version-policy/issue-127/build.sbt

@@ -1,6 +1,7 @@
 ThisBuild / scalaVersion := "2.13.8"
 ThisBuild / resolvers += Resolver.typesafeIvyRepo("releases")
 ThisBuild / versionPolicyIntention := Compatibility.None
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val root =
   project.in(file("."))

sbt-version-policy/src/sbt-test/sbt-version-policy/mima-early-semver/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val `v0-1-0` =
   project.settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/mima-pvp/build.sbt

@@ -1,6 +1,7 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
 ThisBuild / versionScheme := Some("pvp")
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val `v0-1-0` =
   project.settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/mima-semver-spec/build.sbt

@@ -1,6 +1,7 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
 ThisBuild / versionScheme := Some("semver-spec")
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val `v0-1-0` =
   project.settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/run-mima/build.sbt

@@ -1,3 +1,5 @@
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
+
 lazy val core = project
   .settings(
     crossVersion := CrossVersion.disabled,

sbt-version-policy/src/sbt-test/sbt-version-policy/scala-3/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "3.0.0-RC3"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val `v1-0-0` =
   project.settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/simple/build.sbt

@@ -118,7 +118,8 @@ lazy val h = project
 inThisBuild(List(
   scalaVersion := "2.12.11",
   organization := "io.github.alexarchambault.sbtversionpolicy.test",
-  versionPolicyIntention := Compatibility.BinaryCompatible
+  versionPolicyIntention := Compatibility.BinaryCompatible,
+  versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories,
 ))
 
 lazy val check = taskKey[Unit]("")

sbt-version-policy/src/sbt-test/sbt-version-policy/skip-publish/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val v100 =
   project.in(file("v1-0-0")).settings(

sbt-version-policy/src/sbt-test/sbt-version-policy/version-intention-consistency/build.sbt

@@ -1,5 +1,6 @@
 ThisBuild / organization := "com.example"
 ThisBuild / scalaVersion := "2.13.2"
+ThisBuild / versionPolicyPreviousVersionRepositories := CoursierDefaultRepositories
 
 val `v0-1-0` =
   project.settings(