src/Pure/General/mercurial.scala

--- a/src/Pure/General/mercurial.scala	Sat Apr 04 18:05:37 2020 +0200
+++ b/src/Pure/General/mercurial.scala	Sat Apr 04 18:13:05 2020 +0200
@@ -274,7 +274,7 @@
 
           while (repos.importing) {
             progress.echo("Awaiting remote repository ...")
-            Thread.sleep(500)
+            Time.seconds(0.5).sleep
             repos = phabricator.the_repository(repos.phid)
           }