Move Coursier cache check

main/src/main/scala/sbt/MainLoop.scala

@@ -32,10 +32,6 @@ object MainLoop {
   /** Entry point to run the remaining commands in State with managed global logging.*/
   def runLogged(state: State): xsbti.MainResult = {
 
-    // This warns if ~/.coursier/cache is found.
-    // Temporary, remove when updating coursier to 2.0.0 final.
-    lmcoursier.CoursierConfiguration.checkLegacyCache()
-
     // We've disabled jline shutdown hooks to prevent classloader leaks, and have been careful to always restore
     // the jline terminal in finally blocks, but hitting ctrl+c prevents finally blocks from being executed, in that
     // case the only way to restore the terminal is in a shutdown hook.

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

@@ -37,10 +37,18 @@ object LMCoursier {
   private[this] val credentialRegistry: ConcurrentHashMap[(String, String), IvyCredentials] =
     new ConcurrentHashMap
 
+  private[this] lazy val checkLegacyCache: Unit = {
+    // This warns if ~/.coursier/cache is found.
+    // Temporary, remove when updating coursier to 2.0.0 final.
+    lmcoursier.CoursierConfiguration.checkLegacyCache()
+  }
+
   def defaultCacheLocation: File =
     sys.props.get("sbt.coursier.home") match {
       case Some(home) => new File(home).getAbsoluteFile / "cache"
-      case _          => CoursierDependencyResolution.defaultCacheLocation
+      case _ =>
+        checkLegacyCache
+        CoursierDependencyResolution.defaultCacheLocation
     }
 
   def relaxedForAllModules: Seq[(ModuleMatchers, Reconciliation)] =