diff -r 85a3285860d3 -r 67e5d5a2f625 mercurial/httprepo.py
--- a/mercurial/httprepo.py	Mon Oct 26 02:06:23 2009 +0200
+++ b/mercurial/httprepo.py	Sat Oct 17 14:00:41 2009 -0400
@@ -106,8 +106,9 @@
                 proto.startswith('text/plain') or
                 proto.startswith('application/hg-changegroup')):
             self.ui.debug("requested URL: '%s'\n" % url.hidepassword(cu))
-            raise error.RepoError(_("'%s' does not appear to be an hg repository")
-                                  % safeurl)
+            raise error.RepoError(_("'%s' does not appear to be an hg repository:\n"
+                                    "---%%<--- (%s)\n%s\n---%%<---\n")
+                                  % (safeurl, proto, resp.read()))
 
         if proto.startswith('application/mercurial-'):
             try: