BF: generally check for no inappropriate characters in the ssh RI beg…

…inning

datalad/support/network.py

@@ -342,8 +342,12 @@ def _guess_ri_cls(ri):
 
     if not fields['scheme'] and not fields['hostname']:
         parts = _split_colon(ri)
-        if fields['path'] and '@' in fields['path'] \
-                or (len(parts) > 1 and not set(parts[0]).intersection(set('/\\#'))):
+        # if no illegal for hostname/username characters in the first part and
+        if not set(parts[0]).intersection(set('/\\#')) and (
+                fields['path'] and
+                '@' in fields['path'] or
+                len(parts) > 1
+        ):
             # user@host:path/sp1
             # or host_name: (hence parts check)
             # TODO: we need a regex to catch those really, parts check is not suff

datalad/support/tests/test_network.py

@@ -282,6 +282,7 @@ def test_url_samples():
     it is e.g. a file).
     """
     _check_ri('e.com/p/sp:f', PathRI, localpath='e.com/p/sp:f', path='e.com/p/sp:f')
+    _check_ri('user@someho.st/mydir', PathRI, localpath='user@someho.st/mydir', path='user@someho.st/mydir')
 
     # SSHRIs have .port, but it is empty
     eq_(SSHRI(hostname='example.com').port, '')