diff -r 25512a65cefd -r 9e5b4dbe8ff2 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Wed May 27 12:56:13 2020 +0200
+++ b/mercurial/localrepo.py	Sat Jan 18 10:07:07 2020 -0800
@@ -509,6 +509,11 @@
         except OSError as e:
             if e.errno != errno.ENOENT:
                 raise
+        except ValueError as e:
+            # Can be raised on Python 3.8 when path is invalid.
+            raise error.Abort(
+                _(b'invalid path %s: %s') % (path, pycompat.bytestr(e))
+            )
 
         raise error.RepoError(_(b'repository %s not found') % path)