mercurial/revset.py

--- a/mercurial/revset.py	Sat Mar 21 13:27:47 2020 +0900
+++ b/mercurial/revset.py	Sat Mar 21 13:39:39 2020 +0900
@@ -2109,7 +2109,10 @@
         # i18n: "rev" is a keyword
         raise error.ParseError(_(b"rev expects a number"))
     if l not in _virtualrevs:
-        repo.changelog.node(l)  # check that the rev exists
+        try:
+            repo.changelog.node(l)  # check that the rev exists
+        except IndexError:
+            raise error.RepoLookupError(_(b"unknown revision '%d'") % l)
     return subset & baseset([l])